rocketworkbench-devel

Re: [Rocketworkbench-devel] Web page

[Ray C. <ra...@sm...>]

Hi Antoine:

My sincere apologies about the web page.  Tell me what you want, and I'll
do it ASAP.

I completely forgot about it in the work creating the aRocket static test
site.  If you get someone else to do it, I understand, otherwise, I will
put together a basic site over the next day or two.

Ray

On Sun, 9 Apr 2000, Antoine Lefebvre wrote:

> Hi,
> 
> It would be great to have a web page and am wondering if someone is willing to begin this work with me. At least discuss the contents of the page and the layout. 
> 
> Thanks for your help.
> 
> -- 
> Antoine Lefebvre
> ant...@po...
> 
> _______________________________________________
> Rocketworkbench-devel mailing list
> Roc...@li...
> http://lists.sourceforge.net/mailman/listinfo/rocketworkbench-devel
> 

[Rocketworkbench-devel] Web page

[Antoine L. <an...@ti...>]

Hi,

It would be great to have a web page and am wondering if someone is willing to begin this work with me. At least discuss the contents of the page and the layout. 

Thanks for your help.

-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] new page

[Antoine L. <an...@st...>]

Hello,
I have upload a new cgi script to have access to the thermodynamics properties of propeppants and combustions product by web.

http://rocketworkbench.sourceforge.net/properties.html

you can also search identification number by name instead of looking in the big list.

---

Cpropep have some problems finding adiabatic flame temperature when condensed species exist. The equilibrium of the gaz only mixture exist at a low temperature where the condensed often doesn't exist and is unable to add the good one. If somebody have an idea on the way to solve the problem, keep me inform.


-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] documentation

[Antoine L. <an...@st...>]

Hello
I have upload an html version of the documentation I begin to write. The url is http://rocketworkbench.sourceforge.net/cpropep/index.html

I would appreciate any comments about that. There is probably a lot of english mistake, my native language is french...

If some more explanation are needed, please ask and I will add it.

Cpropep is now able to compute adiabatic flame temperature for some mix. As an example, cpropep predict a temperature of 1733 K for the KNO3/Sucrose propellant while propep say 1755. 

I will try to install a new cgi script during the next week to let you experiment with that.

-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] documentation

[Antoine L. <an...@st...>]

Hello,
I uploaded two file in the ftp directory. One is a beginning of documentation on cpropep mathematical theory and algorythm and the second is a resume of the equations in a matrix format.

cpropep.ps and cpropep_a.ps,
you will need ghostview to see the file, you will find windows version easily on the net.

ftp://rocketworkbench.sourceforge.net/pub/rocketworkbench

Please, send me any correction or ask questions if it is not clear enough.


-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] new cgi

[Antoine L. <an...@st...>]

Hello,

I have just install on the web server a cgi script to interface with cpropep on the web. It does just chemical equilibrium for a fixed pressure/temperature point with a specified propellant for the moment.

Try it and give me your comment about this. If you found any english mistake, please report it to me. If something goes wrong with the page, report it also.

http://rocketworkbench.sourceforge.net/equil.html

thanks

-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] cpropep

[Antoine L. <an...@st...>]

I would like to know what are the feature you would like cpropep to have. For the moment, I have think of the following.

1- Compute simple equilibrium at a fixed temperature and pressure

2- Compute chamber equilibrium at fixed pressure and enthalpy of 
   reactant (to find the flame temperature)

3- Compute shifting and frozen equilibrium rocket performance
   considering the equilibrium in 2

4- Optimisation routine to find best composition. Specify a variable 
   component of the propellant and find the greatest possible isp.

Any other idea?   

-- 
Antoine Lefebvre
ant...@po...

Re: [Rocketworkbench-devel] compatibility

[Konrad H. <ko...@ne...>]

Antoine Lefebvre has written:
> 
> I am working on little command line interface for cpropep and am wondering if there is an implementation of getopt() under windozes, it is in unistd.h. It is standard under Linux.
> 
> I wait for an answer before beginning the work.
> 
> -- 
> Antoine Lefebvre
> ant...@po...

Not sure which license path you want to pursue but
getopts is done nicely as a GPL code.

Look for getopt.c and getopt.h.  It does work under
Win31 and Win32.

hth.

-- kjh

[Rocketworkbench-devel] compatibility

[Antoine L. <an...@st...>]

I am working on little command line interface for cpropep and am wondering if there is an implementation of getopt() under windozes, it is in unistd.h. It is standard under Linux.

I wait for an answer before beginning the work.

-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] cpropep

[Antoine L. <an...@st...>]

I have complete today the first working version of cpropep. It compute equilibrium for gazeous phase only. I planed to add condensed species during the week.

I think the result are ok. I try H2/O2 composition and compare with a web base chemical equilibrium calculator and get the same result.

If somebofy want to try, you need both libnum and cpropep available via ftp at
rocketworkbench.sourceforge.net/pub/rocketworkbench

The web chemical equilibrium calculator is at 
http://www.crct.polymtl.ca/fact/web/equiweb.htm


-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] references

[Antoine L. <an...@st...>]

Here is a list of interesting books about equilibrium

This books include a complete listing of the program implementing the theory explain in the books. The code is in fortran

AUTEUR           : Gordon, Sanford.                                                              : McBride, Bonnie J., joint author.                            TITRE            : Computer program for calculation of complex chemical
                   equilibrium compositions, rocket performance, incident and
                   reflected shocks, and Chapman-Jouguet detonations            EDITEUR & DATE   : Washington: Scientific and Technical Information Office,
                   National Aeronautics and Space Administration; [for sale by
                   the National Technical Information Service, Springfield,
                   Va.], 1971. --                                               DESCRIPTION      : viii, 245 p.; 27 cm. - --                                    COLLECTION       : NASA SP (United States, National Aeronautics and Space
                   Administration) ; 273.                                       NOTES            : Errata sheet inserted. Includes bibliographical references.
---------------------------------------------------------------


This book explain all the necessary theory to understand equilibrium, it also include a lot of listing of source code.

AUTEUR           : Smith, William R. (William Robert), 1943-                                     : Missen, Ronald W. (Ronald William), 1928-                    TITRE            : Chemical reaction equilibrium analysis : theory and
                   algorithms                                                   EDITEUR & DATE   : New York : Wiley, c1982. --                                  DESCRIPTION      : xvi, 364 p. : ill. ; 24 cm. --                               ISBN             : 0471093475 :                                                 NOTES            : "A Wiley-Interscience publication." Bibliography: p. 334-341.
                    Includes indexes.
--------------------------------------------------------------------------

This one also explain theory. No source code but table of thermodynamics data.

AUTEUR           : Wilkins, Roger Lawrence.                                     TITRE            : Theoretical evaluation of chemical propellants. --           EDITEUR & DATE   : Englewood Cliffs, N.J. : Prentice-Hall, 1963. --             DESCRIPTION      : xiv, 463 p. : ill. ; 24 cm. --                               COLLECTION       : Prentice-Hall international series in space technology       NOTES            : Comprend des références bibliographiques.


I have found all those books at my engineering university library. You should be able to found to books. If you can't, I could scan some interesting part and send it by email.


-- 
Antoine Lefebvre
ant...@po...
http://pages.infinit.net/linux/rocket/index.html
http://pages.infinit.net/linux/music/music.html

[Rocketworkbench-devel] chemical potential

[Antoine L. <an...@st...>]

I have a question.

The chemical potential for a soecies j at temperature T and pressure P is

uj = ujo + R*T*ln(nj/n) + R*T*ln(P)

with nj: number of mole of species j
     n : total number of mole

I am wondering how the standard chemical potential potential ujo at temperature T is compute in propep.

This value is Habitually
heat of formation at T - T*entropy

The problem come from that the assign enthalpy compute from the coefficient in thermo.dat don't give the heat of formation but another value.

If somebody is able to read the fortran source code and retrieve the formula, it will help.

thanks

-- 
Antoine Lefebvre
ant...@po...
http://pages.infinit.net/linux/rocket/index.html
http://pages.infinit.net/linux/music/music.html

Re: [Rocketworkbench-devel] cpropep

[Antoine L. <an...@st...>]

I have receice an email from JimSwen that explain a little bit the low participation we have presently on the list. I will try to answer those question.


On Wed, Feb 23, 2000 at 05:18:10AM -0500, Ji...@ao... wrote:
> Antoine-
> 
> Ever since you started the [Rocketworkbench-devel] list,
> I have been cut off from the discussion, because none of the references or 
> archives are available to me.
> 
> In a little while I will install a CVS client and be able to see your source 
> codes, but for now it is not fun or productive.
Well, first of all, I put archive in zip format in the anonymous ftp for the people who don't have cvs. The address is 
ftp rocketworkbench.sourceforge.net/pub/rocketworkbench

every things are on this directory and I upgrade the package for every significant change.

> 
> Then you refer to "the book from the nasa" with no clear specifics.
> "Computer program for calculation of complex chemical
> equilibrium compositions, rocket performance, incident and
> reflected shocks, and Chapman-Jouguet detonations": is that really the exact 
> title?  What is the year of publication, or the NASA publication number, or 
> other number?  Is it available at some URL?
It is the specific title, I will give specific information later since the book is at the library...

> 
> I should be able to help with the fortran code, and I would like to see if it 
> resembles the composition-adjustment which was done in propep.
They seem to use a better algorythm that let you begin the iteration matrix with a first approximation of the mole number that do not satisfy the mass-balance. The matrix converge itself to a good solution. I don't understand yet all the detail.

> 
> I looked at the  [Rocketworkbench-devel]  page, and can't see any links to 
> any archive other than the e-mail.  Ray's page wasn't up yet, when I looked.  
>  Even the CVS server only shows up by magic, after I install it.
Yes, the Ray's page will help to explain. For the cvs, you can also browse the file by the web site of sourceforge. You just have to go in the project page. (do a search by the main page) and click on the item cvs. They will give you a link to browse the files.

> 
> Are you getting a lot of participation from others?
> This kind of tightly closed structure always cuts me out.
> This may not be a large, professional programming project in its early 
> phases, and you don't have a large cadre of professional prgrammers helping.
For the moment the participation is low. I would like to get more professional but I think we must do more publicity. Probably we will have more people when we release a first working version of a software.

If you have any idea on the way to improve the actual situation, just talk me about.

> 
> Is there a way we could have an archive page of simple uploaded files?
> We are going to need all types: c, fortran, gifs, bibliographies in html, 
> outlines in Power-Point...
For the moment, we have an anonymous ftp. If you want to be able to upload file, you must register as a user at sourceforge.net and send me your user name and user id. I can then add you to the developper list and give you permission. The problem, for the windows user is that every thing a done with encryption (ssh and scp) so I don't think those two exist on windows. 

> I can help with some of my pages if others aren't readily available or you 
> don't want the extra work.
I am open to any suggestion that will help.

I will send a complete bibliograhy of the books a presently work with by the end of the day.

-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] cpropep

[Antoine L. <an...@st...>]

Hello,

I finally decide to implement the theory of the book from the nasa,
Computer program for calculation of complex chemical
equilibrium compositions, rocket performance, incident and
reflected shocks, and Chapman-Jouguet detonations   

I implement the matrix to solve problem with fixed temperature and pressure. I don't see however how to compute the new mixture approximation from the Lagrange multiplier and other parameter. If someone here have an idea, I would like to know. 

There is the complete source code in the book but I have problem to understand the fortran and don't see how they do.

I wait your comments

-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] rocket.h

[Antoine L. <an...@st...>]

Hello,

I have read the rocket.h of Konrad and have done some modifications. I join a new version with comments and new idea. Please take a looks and give me your opinion.

bye


-- 
Antoine Lefebvre
ant...@po...
http://pages.infinit.net/linux/rocket/index.html
http://pages.infinit.net/linux/music/music.html

Re: [Rocketworkbench-devel] rocket description

[LarryC <cu...@te...>]

Konrad,

Not sure what team you're talking about, but I'm 99.9% sure I'd like to
join :) Your characterization of my dissatisfation with DATCOM is
correct. I am, however, interested in comparing datcom Cd curves with 
those from accelerometers. I applaud your inclusion of Cd/velocity and
Cd mach number relationships in your code. 

Rock On,
-Larry C.

On Tue, 15 Feb 2000, Konrad Hambrick wrote:

> Antoine Lefebvre has written:
> > 
> > Hello,
> > 
> > I have take a look to the Konrad Hambrick rocket profiler and it is very interesting. I suppose it is possible to compute a lot of parameter just by geometrical analisys. It could be a start point to a full rocket caracterisation. If I understand, the profiller compute the CG, and the CP of the rocket (no drag factor of other aerodynamic factor). 
> > There is other value computed by this rocket profiler?
> > 
> > To upgrade the capability of the profiler, we could add information about surface finish and density of different part of the rocket. 
> > 
> > I could be great to add this software in cvs and ftp. Maybe begin to tranlate it in C before. (Could use flex as the file parser).
> > 
> > I will read the code during the week and try to understand it all.
>  
> 
> Antoine --
> 
> Profiler computes the stability info and outputs enough info
> for gnuplot to 'draw' a picture of the rocket with the CLA
> ( center of lateral area ) and CP ( Barrowman Center of 
> Pressure ) marked.
> 
> Various 'standard shapes' are programmed in -- ogive, parabolic
> and elliptical including the shape itself and the 1st and 2nd
> moments.
> 
> It does not yet compute CG from geometry & physical properties.
> That was the next feature I was to add ( back in '96, before
> the AltAcc distracted me ;-)
> 
> The CG and Radial and Longtudinal Moments can be entered directly
> and profiler will compute the Dynamic Stability parameters.  Run
> the mi.pro, hjohn.pro and grad.pro.  I constructed a torsion
> wire and measured the IR and IL and CG and entered the results
> in the .pro files for these rockets.
> 
> Of interest here:  The hjohn and grad are rock(et)-solid stable,
> the mi is dynamically unstable and I wanted to find out why ...
> 
> re:  Mark's Q's,  The CG can be computed by taking a different
> moment than the CLA.  Like I said, I was working on adding it
> but I have been distracted by my real job and the AltAcc.
> 
> I was working on a materials database and also on allowing for
> direct entry.
> 
> As far as computing CD from the geometry -- it is possible but
> as far as practicality goes, other model rocket CD calculators
> based on DATCOM have produced dubious results at best.
> 
> I was looking at using Accelerometer-Based data.  I have some
> excellent results on the LOC Vulcanite, scaled both down and
> up ( 1.9 in-diam, 2.25 in, and 2.9 in ) and I am building
> a 3.99 inch for a Level 3 attempt. 
> 
> This is why the CD-vs-Mach linked-list was included in my
> rocket.h file.  I planned to allow for experimental data
> in the 'physical properties' section.  Experimental data
> would override computed physical properties.
> 
> The Drag vs Velocity data for the Vulcanite series are online
> at:  ftp://ftp.netcom.com/pub/ko/konrad/
> 
> The files to look at are:
> 
>    vulet-dr.gif  -- 1.9  in scaled down LOC Vulcanite ( Vulcanette )
>    vul-dr.gif    -- 2.25 in Vulcanite ( Spock's Johnson )
>    nm-dr.gif     -- 2.9  in scaped up Vulcanite ( Nocturnal Missions )
> 
> For each I have fit a 2nd degree polynomial to the subsonic Drag vs
> Velocity.  Each has gone supersonic and each shows the transonic drag
> divergance in the Force vs Velocity data.
> 
> Larry Curcio has already implemented DATCOM but he is not
> happy with the results on modrocket-scaled vehicles.
> 
> I am sending him a cc of this elm.  He would be an invaluable addition 
> to the team.   Larry has already implemented most of the aero and sim 
> stuff we are discussing.
> 
> -- kjh
> 
> cc:  LarryC ( cu...@te... )
> 

Re: [Rocketworkbench-devel] rocket description

[Konrad H. <ko...@ne...>]

Antoine Lefebvre has written:
> 
> Hello,
> 
> I have take a look to the Konrad Hambrick rocket profiler and it is very interesting. I suppose it is possible to compute a lot of parameter just by geometrical analisys. It could be a start point to a full rocket caracterisation. If I understand, the profiller compute the CG, and the CP of the rocket (no drag factor of other aerodynamic factor). 
> There is other value computed by this rocket profiler?
> 
> To upgrade the capability of the profiler, we could add information about surface finish and density of different part of the rocket. 
> 
> I could be great to add this software in cvs and ftp. Maybe begin to tranlate it in C before. (Could use flex as the file parser).
> 
> I will read the code during the week and try to understand it all.
 

Antoine --

Profiler computes the stability info and outputs enough info
for gnuplot to 'draw' a picture of the rocket with the CLA
( center of lateral area ) and CP ( Barrowman Center of 
Pressure ) marked.

Various 'standard shapes' are programmed in -- ogive, parabolic
and elliptical including the shape itself and the 1st and 2nd
moments.

It does not yet compute CG from geometry & physical properties.
That was the next feature I was to add ( back in '96, before
the AltAcc distracted me ;-)

The CG and Radial and Longtudinal Moments can be entered directly
and profiler will compute the Dynamic Stability parameters.  Run
the mi.pro, hjohn.pro and grad.pro.  I constructed a torsion
wire and measured the IR and IL and CG and entered the results
in the .pro files for these rockets.

Of interest here:  The hjohn and grad are rock(et)-solid stable,
the mi is dynamically unstable and I wanted to find out why ...

re:  Mark's Q's,  The CG can be computed by taking a different
moment than the CLA.  Like I said, I was working on adding it
but I have been distracted by my real job and the AltAcc.

I was working on a materials database and also on allowing for
direct entry.

As far as computing CD from the geometry -- it is possible but
as far as practicality goes, other model rocket CD calculators
based on DATCOM have produced dubious results at best.

I was looking at using Accelerometer-Based data.  I have some
excellent results on the LOC Vulcanite, scaled both down and
up ( 1.9 in-diam, 2.25 in, and 2.9 in ) and I am building
a 3.99 inch for a Level 3 attempt. 

This is why the CD-vs-Mach linked-list was included in my
rocket.h file.  I planned to allow for experimental data
in the 'physical properties' section.  Experimental data
would override computed physical properties.

The Drag vs Velocity data for the Vulcanite series are online
at:  ftp://ftp.netcom.com/pub/ko/konrad/

The files to look at are:

   vulet-dr.gif  -- 1.9  in scaled down LOC Vulcanite ( Vulcanette )
   vul-dr.gif    -- 2.25 in Vulcanite ( Spock's Johnson )
   nm-dr.gif     -- 2.9  in scaped up Vulcanite ( Nocturnal Missions )

For each I have fit a 2nd degree polynomial to the subsonic Drag vs
Velocity.  Each has gone supersonic and each shows the transonic drag
divergance in the Force vs Velocity data.

Larry Curcio has already implemented DATCOM but he is not
happy with the results on modrocket-scaled vehicles.

I am sending him a cc of this elm.  He would be an invaluable addition 
to the team.   Larry has already implemented most of the aero and sim 
stuff we are discussing.

-- kjh

cc:  LarryC ( cu...@te... )

[Rocketworkbench-devel] rocket description

[Antoine L. <an...@st...>]

Hello,

I have take a look to the Konrad Hambrick rocket profiler and it is very interesting. I suppose it is possible to compute a lot of parameter just by geometrical analisys. It could be a start point to a full rocket caracterisation. If I understand, the profiller compute the CG, and the CP of the rocket (no drag factor of other aerodynamic factor). 
There is other value computed by this rocket profiler?

To upgrade the capability of the profiler, we could add information about surface finish and density of different part of the rocket. 

I could be great to add this software in cvs and ftp. Maybe begin to tranlate it in C before. (Could use flex as the file parser).

I will read the code during the week and try to understand it all.

-----------------------
Here is a summary of the actual projects states

 * propellant combustion simulation/design
 	=> cpropep is in the way, I am trying to set up a set of iterative equation
 	   to solve the problem of equilibrium
 * Grain Design
 * Chamber/Injector design
 * Nozzle Design
 * Trajectory analysis
 	=> there is a first version of a flight simulator, need a lot of work.
 	   It is in c++ for the moment, we should decide if we keep it in c++
 	   or redesign in c, or other. Need comments about you.
 * Impact Dispersal profiles.
 * Basic parachute design
 * Physical Description and analysis
 	=> Konrad Hambrick have a rocket profiler already done. Could start with that
 	   to made a complete geometrical analysis tool for rockets
 * Numerical method for solving problems
	=> Some solver for matrix (LU factorisation and gauss elimination)
	   Runge-Kutta of 4th order for differential systems
 



-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] Re: Runge-Kutta

[Konrad H. <ko...@ne...>]

> FROM: Antoine Lefebvre
> DATE: 02/09/2000 10:05:24
> SUBJECT:  [Rocketworkbench-devel] Runge-Kutta
> 
> Hello,
> 
> I am looking for C library implementing the Runge-Kutta method for solving
> systems of EDO of the first order.
> 
> Any idea?
> 
> I have only found fortran source.
> 
> I will begin to write this solver for the flight simulation program. I
> will put code in libnum when it will be done. I somebody want to help,
> you are welcome.
> 
> -- 
> Antoine Lefebvre

Antoine --

This is covered very well in _Numerical_Recipes_in_C_

I will get back after looking at libum.

-- kjh

Re: [Rocketworkbench-devel] Kickoff Elm

[Konrad H. <ko...@ne...>]

Antoine Lefebvre has written:
> 
> On Sun, Feb 13, 2000 at 09:42:46AM -0800, Konrad Hambrick wrote:
> > All --
> > 
> > What will be the scope of the Rocket WorkBench ?
> > 
> > My wish list would be:
> > 
> >    1. Physical Description
> >    2. Aerodynamics ( Drag and Stability )
> 
> Could you explain those two
>
> >    3. Powerplant 
> >    4. Environmental

Antoine --

Powerplant is the motor / engine 
Environmental is Launch site, atmospheric, etc.

> 
> The list was for the moment 
> 
> * propellant combustion simulation/design
> * Grain Design
> * Chamber/Injector design
> * Nozzle Design
> * Trajectory analysis
> * Impact Dispersal profiles.
> * Basic parachute design
> 
> I'm ready to work on any rocket related project that could help design and understanding of rocket...

Cool.

All I would add to your list is rocket geometry asd physical
properties.

You might want to check out program profiler.  It is a program
than computes static and dynamic stability parameters from a 
physical description of the rocket.  Implemented in awk, it
is portable and fairly easily translated to c-code.

The program is at ftp://ftp.netcom.com/pub/ko/konrad/rawketry/

The file is profv100.zip

There is a howto in profiler.txt.  For examples of profiler and
dynamic stability calculations, see grad.pro, mi.pro and hjohn.pro.

It will run pretty much out of the box on a linux system and there
are some dos .bat files and a list of programs to install for a
windows pc ( gawk, gnuplot, and ghostscript ).

> > I suppose we might want to begin with a data structure
> > that describes a rocket.  I started working on a similar
> > project a few years ago but ran out of time between my
> > real job and my work on the AltAcc.
> > 
> > Below is my first stab at a data structure describing a
> > rocket.  It is nowhere near complete or even correct as
> > far as it goes.  it is a start.
> > 
> > Input ?
> > 
> > Let's get ready to rumble !
> > 
> > -- kjh
> 
> Please take a look to the stock I have put in libsimulation on the cvs or ftp
> ftp rocketworkbench.sourceforge.net/pub/rocketworkbench
> 
> I have already do a part of this but not in the same manner. My rocket description file use aerodynamic properties: drag coefficient, lift coefficient, cross-spin coefficient, restoring moment coefficient, damping moment coefficient,...


These are parameters that profiler calculates from geometric
and physical properties of the rocket.  Might have a fit here.


> All the aerodynamic parameter to describe the rocket attitude. Of course this method implies that we know those value. If we describe a rocket like you would like to do, it could permit the calculation of aerodynamic properties if we are able to simulate the comportmnent of a body in a compressible fluid. Maybe by finite element analysis if someone know how to do...

I will take a look at the libraries from the ftp site and
get back to you.


> > /************************** rocket.h ********************************/
> > 
> > struct AtmProf                /* optional Atmospheric Info for Sims */
> > {
> >    AtmProf * prev;            /* linked list ... pointer to prev element */
> >    AtmProf * next;            /* linked list ... pointer to next element */
> >    double    alt;             /* altitude of measurement */
> >    double    press;           /* measured barometric pressure */
> >    double    temp;            /* measured temperature */
> >    double    humidity;        /* measured humidity */
> >    double    rho;             /* computed air density */
> >    double    viscosity;       /* computed air viscosity */
> >    double    dirwind;         /* measured wind direction (NSEW) */
> >    double    velwind;         /* measured wind velocity */
> > };
> Humm, interesting. Is it really possible to know those parameter for each point of the atmosphere around the earth...

I was involved in a NASA project a few years back and they launched
a radiosonde baloon just prior to launching the rockets.  Otherwise,
these are to a practical degree computable from the ISA or they can
be had from several web sites,  One that is fun to look at is:

   http://cirrus.sprl.umich.edu/wxnet/maps.html 

Look at the Raw/Graphical Sounding Data in the lower right corner,
select text and click on a local weather station site.

 
> For the moment, I use a simple formula that compute the density of the atmosphere in function of altitude considering a compressible fluid and variable gravitational acceleration. It is easy to demonstrate from a differential equation.
> 
> density = (Po*M/T)*exp( ((M*G*Mt)/R*T) * (1/(Rt + h) - 1/Rt))
>
> Po: ground pressure
> M: molar mass of atmosphere
> T: temperature
> G: universal gravitational constant
> Mt: earth mass
> R: perfect gaz constant
> Rt: radius of the earth
> h: altitude
> 
> It give a fairly good approximation for low altitude.

Looks familiar.  The ISA is also available up into the Thermosphere.

 
> 
> > struct Site                   /* Launch Site Environmental Data */
> > {
> >    double      ialt;           /* Site Altitude */
> >    double      bpress;         /* Site Barometric Pressure */
> >    double      temp;           /* Site Temperature */
> >    double      rho0;           /* Site Air Density ( computed ) */
> 
> Should add site position around a planet, it is important to
> take care of coriolis acceleration

Great Idea !

> 
> >    double      rodlen;         /* Launch Rod Length */
> 
> There is not always rod, especially for big rockets
> 
> >    double      theta;          /* Launch Angle */

> Two angles are needed

Correct, as is the wind direction and speed at Ground Level.

> >    double      falt;           /* Final Altitude for Sim ( crash Alt ;-) */
> If the rocket goes in orbit?

Hmmm ... I hadn't gone there ( yet ;-)
Another good idea.

 
> >    atmos     * AtmProf;        /* [O] pointer to Atmospheric Profile */
> > };
> 
> We could also add information about plenets, mass, radius...
> > 
> > struct CD                      /* optional CD vs Velocity data */
> > {
> >    CD       *  next;           /* linked list; pointer to previous */
> >    CD       *  prev ;
> >    double      mach;           /* mach number */
> >    double      rnumber;        /* computed Reynolds Number */
> >    double      coff;           /* CD at CD.mach */
> > };
> > 
> > struct Vertex                  /* Fin Vertices Details */
> > {
> >    Vertex    * prev;           /* linked list */
> >    Vertex    * next;
> >    double      z;
> >    double      r;
> > };
> > 
> > struct Fins                    /* Fin Geometry Info */
> > {
> >    int         numfin;         /* number of fins */
> >    double      offset;         /* offset from leading tip of stage */
> >    double      thickness;      /* max thickness */
> >    double      farea;          /* fin surface area  */
> >    int         shape;          /* enumerated fin shape ( Poly, Para, Ellip */
> >    int         numvert;        /* number of vertices */
> >    Vertex   *  vertices;       /* [O] optional pointer to Vertex.z, .r */
> >    double      fdiam;          /* diameter at front of fin can */
> >    double      rdiam;          /* diameter at rear of fin can */
> >    double      span;           /* fin span */
> >    double      root;           /* root chord length */
> >    double      tip;            /* tip chord length */
> >    double      midchord;       /* mid chord length */
> >    double      sweepback ;     /* sweepback distance */
> >    double      parea;          /* plan area of fincan */
> >    double      aspectratio;    /* aspect ratio */
> > };
> > 
> > struct Thrust                  /* Linked List Thrust Curve Tuples */
> > {
> >    Thrust   *  next;
> >    Thrust   *  prev;
> >    double      time;
> >    double      thrust;
> > };
> > 
> > struct Motor                  /* Stolen from RASP ;-) */
> > {
> >     char    *  name;          /* engine name */
> >     char    *  mfg;           /* manufacturer info */
> >     double     diam;          /* engine diameter    (millimeters) */
> >     double     len;           /* engine length      (millimeters) */
> >     double     mass;          /* initial engine wt. (kilograms) */
> >     double     promass;       /* propellant wt.     (kilograms) */
> >     double     dtime;         /* thrust duration    (seconds) */
> >     Thrust  *  tcurve;        /* thrust curve     (Time-sec,Thrust-Newtons) */
> >     double     i_avg;         /* average thrust     (newtons) */
> >     double     i_tot;         /* total impulse      (newton-seconds) */
> >     double     i_max;         /* peak thrust        (newtons) */
> >     char    *  delay;         /* ejection delays available (sec) */
> >     Motor   *  next;          /* linked list of motors */
> > };
> > 
> > struct Stage                     /* stolen from rasp v4.1 -- needs more !  */
> > {
> >    int         nose ;            /* nose type on stage                      */
> >    double      length;           /* length of stage                         */
> >    double      diameter;         /* max diameter of stage                   */
> >    CD       *  cd;               /* kjh added cd per stage                  */
> >    double      totalw;           /* launch wt of stage ( w/ motors(s) )     */
> >    double      dryw;             /* dry stage wt ( w/o motor(s) )           */
> >    double      prowt;            /* propellant wt of all motors             */
> >    Motor    *  motors;           /* pointer to motor structure              */
> >    double      itime;            /* Start of motors ( time since LO )       */
> >    double      etime;            /* End of engine burn  ( absolute time )   */
> >    double      dtime;            /* When is the Stage dropped from the rest */
> >    Thrust   *  thrust;           /* sum of all motors or ->motors.tcurve    */
> >    Fin      *  fins;             /* finfo for stage                         */
> >    Stage    *  next;             /* next Stage ( From Bottom, Up )          */
> >    Stage    *  prev;             /* previous Stage ( just burned out )      */
> > };
> > 
> > struct Rocket                                  /* What is in a rocket */
> > {
> >    char     *  name;
> >    int         nose ;
> >    double      diameter;
> >    double      length ;
> >    Stage    *  stages ;
> >    Site     *  environ ;
> > };
> > 
> > 
> > struct NoseCones {
> >     char    * name ;    /* Verbose Nose Cone Name */
> >     int       form ;    /* M,C&B Formula to Apply */
> > }
> >    Noses [ ] =
> >    {
> >       "undefined",      1 ,
> >       "ogive",          1 ,
> >       "conic",          1 ,
> >       "elliptic",       2 ,
> >       "parabolic",      2 ,
> >       "blunt",          2
> >    } ;
> > 
> > struct FinShapes {
> >     char    * name ;    /* Verbose Fin Shape Name */
> >     int       form ;    /* Enum Data  */
> > }
> >    FinShape [ ] =
> >    {
> >       "undefined",      0 ,
> >       "polygonal",      1 ,
> >       "elliptical",     2 ,
> >       "parabolic",      3 
> >    } ;
> > 
> > #define NUMFINTYPE ( sizeof FinShapes / sizeof ( struct FinShape ))
> 
> I will look how those idea could be include in the actual simulator. There is a lot of good idea. If you want to look at that on your own, you can send me patch of the code.

I will.  While I am thinking abot it, Larry Curcio has done a lot of
work in developing a Rocket Workbench.  I wonder if I could send him
an invitation to the group ?

> 
> Another question, there is somebody who have experiences with finite element analysis and Navier-Stroke equations??

I did some FE analyses a few years ago.  I will dust off some old
Fortran and c-code and get back.

Re: [Rocketworkbench-devel] Kickoff Elm

[Antoine L. <an...@st...>]

On Sun, Feb 13, 2000 at 09:42:46AM -0800, Konrad Hambrick wrote:
> All --
> 
> What will be the scope of the Rocket WorkBench ?
> 
> My wish list would be:
> 
>    1. Physical Description
>    2. Aerodynamics ( Drag and Stability )

Could you explain those two
>    3. Powerplant 
>    4. Environmental

The list was for the moment 

* propellant combustion simulation/design
* Grain Design
* Chamber/Injector design
* Nozzle Design
* Trajectory analysis
* Impact Dispersal profiles.
* Basic parachute design

I'm ready to work on any rocket related project that could help design and understanding of rocket...


>    
> I suppose we might want to begin with a data structure
> that describes a rocket.  I started working on a similar
> project a few years ago but ran out of time between my
> real job and my work on the AltAcc.
> 
> Below is my first stab at a data structure describing a
> rocket.  It is nowhere near complete or even correct as
> far as it goes.  it is a start.
> 
> Input ?
> 
> Let's get ready to rumble !
> 
> -- kjh

Please take a look to the stock I have put in libsimulation on the cvs or ftp
ftp rocketworkbench.sourceforge.net/pub/rocketworkbench

I have already do a part of this but not in the same manner. My rocket description file use aerodynamic properties: drag coefficient, lift coefficient, cross-spin coefficient, restoring moment coefficient, damping moment coefficient,...

All the aerodynamic parameter to describe the rocket attitude. Of course this method implies that we know those value. If we describe a rocket like you would like to do, it could permit the calculation of aerodynamic properties if we are able to simulate the comportmnent of a body in a compressible fluid. Maybe by finite element analysis if someone know how to do...


> 
> /************************** rocket.h ********************************/
> 
> struct AtmProf                /* optional Atmospheric Info for Sims */
> {
>    AtmProf * prev;            /* linked list ... pointer to prev element */
>    AtmProf * next;            /* linked list ... pointer to next element */
>    double    alt;             /* altitude of measurement */
>    double    press;           /* measured barometric pressure */
>    double    temp;            /* measured temperature */
>    double    humidity;        /* measured humidity */
>    double    rho;             /* computed air density */
>    double    viscosity;       /* computed air viscosity */
>    double    dirwind;         /* measured wind direction (NSEW) */
>    double    velwind;         /* measured wind velocity */
> };
Humm, interesting. Is it really possible to know those parameter for each point of the atmosphere around the earth...

For the moment, I use a simple formula that compute the density of the atmosphere in function of altitude considering a compressible fluid and variable gravitational acceleration. It is easy to demonstrate from a differential equation.

density = (Po*M/T)*exp( ((M*G*Mt)/R*T) * (1/(Rt + h) - 1/Rt))

Po: ground pressure
M: molar mass of atmosphere
T: temperature
G: universal gravitational constant
Mt: earth mass
R: perfect gaz constant
Rt: radius of the earth
h: altitude

It give a fairly good approximation for low altitude.

> struct Site                   /* Launch Site Environmental Data */
> {
>    double      ialt;           /* Site Altitude */
>    double      bpress;         /* Site Barometric Pressure */
>    double      temp;           /* Site Temperature */
>    double      rho0;           /* Site Air Density ( computed ) */

Should add site position around a planet, it is important to
take care of coriolis acceleration

>    double      rodlen;         /* Launch Rod Length */

There is not always rod, especially for big rockets

>    double      theta;          /* Launch Angle */
Two angles are needed
>    double      falt;           /* Final Altitude for Sim ( crash Alt ;-) */
If the rocket goes in orbit?

>    atmos     * AtmProf;        /* [O] pointer to Atmospheric Profile */
> };

We could also add information about plenets, mass, radius...
> 
> struct CD                      /* optional CD vs Velocity data */
> {
>    CD       *  next;           /* linked list; pointer to previous */
>    CD       *  prev ;
>    double      mach;           /* mach number */
>    double      rnumber;        /* computed Reynolds Number */
>    double      coff;           /* CD at CD.mach */
> };
> 
> struct Vertex                  /* Fin Vertices Details */
> {
>    Vertex    * prev;           /* linked list */
>    Vertex    * next;
>    double      z;
>    double      r;
> };
> 
> struct Fins                    /* Fin Geometry Info */
> {
>    int         numfin;         /* number of fins */
>    double      offset;         /* offset from leading tip of stage */
>    double      thickness;      /* max thickness */
>    double      farea;          /* fin surface area  */
>    int         shape;          /* enumerated fin shape ( Poly, Para, Ellip */
>    int         numvert;        /* number of vertices */
>    Vertex   *  vertices;       /* [O] optional pointer to Vertex.z, .r */
>    double      fdiam;          /* diameter at front of fin can */
>    double      rdiam;          /* diameter at rear of fin can */
>    double      span;           /* fin span */
>    double      root;           /* root chord length */
>    double      tip;            /* tip chord length */
>    double      midchord;       /* mid chord length */
>    double      sweepback ;     /* sweepback distance */
>    double      parea;          /* plan area of fincan */
>    double      aspectratio;    /* aspect ratio */
> };
> 
> struct Thrust                  /* Linked List Thrust Curve Tuples */
> {
>    Thrust   *  next;
>    Thrust   *  prev;
>    double      time;
>    double      thrust;
> };
> 
> struct Motor                  /* Stolen from RASP ;-) */
> {
>     char    *  name;          /* engine name */
>     char    *  mfg;           /* manufacturer info */
>     double     diam;          /* engine diameter    (millimeters) */
>     double     len;           /* engine length      (millimeters) */
>     double     mass;          /* initial engine wt. (kilograms) */
>     double     promass;       /* propellant wt.     (kilograms) */
>     double     dtime;         /* thrust duration    (seconds) */
>     Thrust  *  tcurve;        /* thrust curve     (Time-sec,Thrust-Newtons) */
>     double     i_avg;         /* average thrust     (newtons) */
>     double     i_tot;         /* total impulse      (newton-seconds) */
>     double     i_max;         /* peak thrust        (newtons) */
>     char    *  delay;         /* ejection delays available (sec) */
>     Motor   *  next;          /* linked list of motors */
> };
> 
> struct Stage                     /* stolen from rasp v4.1 -- needs more !  */
> {
>    int         nose ;            /* nose type on stage                      */
>    double      length;           /* length of stage                         */
>    double      diameter;         /* max diameter of stage                   */
>    CD       *  cd;               /* kjh added cd per stage                  */
>    double      totalw;           /* launch wt of stage ( w/ motors(s) )     */
>    double      dryw;             /* dry stage wt ( w/o motor(s) )           */
>    double      prowt;            /* propellant wt of all motors             */
>    Motor    *  motors;           /* pointer to motor structure              */
>    double      itime;            /* Start of motors ( time since LO )       */
>    double      etime;            /* End of engine burn  ( absolute time )   */
>    double      dtime;            /* When is the Stage dropped from the rest */
>    Thrust   *  thrust;           /* sum of all motors or ->motors.tcurve    */
>    Fin      *  fins;             /* finfo for stage                         */
>    Stage    *  next;             /* next Stage ( From Bottom, Up )          */
>    Stage    *  prev;             /* previous Stage ( just burned out )      */
> };
> 
> struct Rocket                                  /* What is in a rocket */
> {
>    char     *  name;
>    int         nose ;
>    double      diameter;
>    double      length ;
>    Stage    *  stages ;
>    Site     *  environ ;
> };
> 
> 
> struct NoseCones {
>     char    * name ;    /* Verbose Nose Cone Name */
>     int       form ;    /* M,C&B Formula to Apply */
> }
>    Noses [ ] =
>    {
>       "undefined",      1 ,
>       "ogive",          1 ,
>       "conic",          1 ,
>       "elliptic",       2 ,
>       "parabolic",      2 ,
>       "blunt",          2
>    } ;
> 
> struct FinShapes {
>     char    * name ;    /* Verbose Fin Shape Name */
>     int       form ;    /* Enum Data  */
> }
>    FinShape [ ] =
>    {
>       "undefined",      0 ,
>       "polygonal",      1 ,
>       "elliptical",     2 ,
>       "parabolic",      3 
>    } ;
> 
> #define NUMFINTYPE ( sizeof FinShapes / sizeof ( struct FinShape ))

I will look how those idea could be include in the actual simulator. There is a lot of good idea. If you want to look at that on your own, you can send me patch of the code.

Another question, there is somebody who have experiences with finite element analysis and Navier-Stroke equations??

> 
> 
> _______________________________________________
> Rocketworkbench-devel mailing list
> Roc...@li...
> http://lists.sourceforge.net/mailman/listinfo/rocketworkbench-devel

-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] Kickoff Elm

[Konrad H. <ko...@ne...>]

All --

What will be the scope of the Rocket WorkBench ?

My wish list would be:

   1. Physical Description
   2. Aerodynamics ( Drag and Stability )
   3. Powerplant 
   4. Environmental
   
I suppose we might want to begin with a data structure
that describes a rocket.  I started working on a similar
project a few years ago but ran out of time between my
real job and my work on the AltAcc.

Below is my first stab at a data structure describing a
rocket.  It is nowhere near complete or even correct as
far as it goes.  it is a start.

Input ?

Let's get ready to rumble !

-- kjh

/************************** rocket.h ********************************/

struct AtmProf                /* optional Atmospheric Info for Sims */
{
   AtmProf * prev;            /* linked list ... pointer to prev element */
   AtmProf * next;            /* linked list ... pointer to next element */
   double    alt;             /* altitude of measurement */
   double    press;           /* measured barometric pressure */
   double    temp;            /* measured temperature */
   double    humidity;        /* measured humidity */
   double    rho;             /* computed air density */
   double    viscosity;       /* computed air viscosity */
   double    dirwind;         /* measured wind direction (NSEW) */
   double    velwind;         /* measured wind velocity */
};
struct Site                   /* Launch Site Environmental Data */
{
   double      ialt;           /* Site Altitude */
   double      bpress;         /* Site Barometric Pressure */
   double      temp;           /* Site Temperature */
   double      rho0;           /* Site Air Density ( computed ) */
   double      rodlen;         /* Launch Rod Length */
   double      theta;          /* Launch Angle */
   double      falt;           /* Final Altitude for Sim ( crash Alt ;-) */
   atmos     * AtmProf;        /* [O] pointer to Atmospheric Profile */
};

struct CD                      /* optional CD vs Velocity data */
{
   CD       *  next;           /* linked list; pointer to previous */
   CD       *  prev ;
   double      mach;           /* mach number */
   double      rnumber;        /* computed Reynolds Number */
   double      coff;           /* CD at CD.mach */
};

struct Vertex                  /* Fin Vertices Details */
{
   Vertex    * prev;           /* linked list */
   Vertex    * next;
   double      z;
   double      r;
};

struct Fins                    /* Fin Geometry Info */
{
   int         numfin;         /* number of fins */
   double      offset;         /* offset from leading tip of stage */
   double      thickness;      /* max thickness */
   double      farea;          /* fin surface area  */
   int         shape;          /* enumerated fin shape ( Poly, Para, Ellip */
   int         numvert;        /* number of vertices */
   Vertex   *  vertices;       /* [O] optional pointer to Vertex.z, .r */
   double      fdiam;          /* diameter at front of fin can */
   double      rdiam;          /* diameter at rear of fin can */
   double      span;           /* fin span */
   double      root;           /* root chord length */
   double      tip;            /* tip chord length */
   double      midchord;       /* mid chord length */
   double      sweepback ;     /* sweepback distance */
   double      parea;          /* plan area of fincan */
   double      aspectratio;    /* aspect ratio */
};

struct Thrust                  /* Linked List Thrust Curve Tuples */
{
   Thrust   *  next;
   Thrust   *  prev;
   double      time;
   double      thrust;
};

struct Motor                  /* Stolen from RASP ;-) */
{
    char    *  name;          /* engine name */
    char    *  mfg;           /* manufacturer info */
    double     diam;          /* engine diameter    (millimeters) */
    double     len;           /* engine length      (millimeters) */
    double     mass;          /* initial engine wt. (kilograms) */
    double     promass;       /* propellant wt.     (kilograms) */
    double     dtime;         /* thrust duration    (seconds) */
    Thrust  *  tcurve;        /* thrust curve     (Time-sec,Thrust-Newtons) */
    double     i_avg;         /* average thrust     (newtons) */
    double     i_tot;         /* total impulse      (newton-seconds) */
    double     i_max;         /* peak thrust        (newtons) */
    char    *  delay;         /* ejection delays available (sec) */
    Motor   *  next;          /* linked list of motors */
};

struct Stage                     /* stolen from rasp v4.1 -- needs more !  */
{
   int         nose ;            /* nose type on stage                      */
   double      length;           /* length of stage                         */
   double      diameter;         /* max diameter of stage                   */
   CD       *  cd;               /* kjh added cd per stage                  */
   double      totalw;           /* launch wt of stage ( w/ motors(s) )     */
   double      dryw;             /* dry stage wt ( w/o motor(s) )           */
   double      prowt;            /* propellant wt of all motors             */
   Motor    *  motors;           /* pointer to motor structure              */
   double      itime;            /* Start of motors ( time since LO )       */
   double      etime;            /* End of engine burn  ( absolute time )   */
   double      dtime;            /* When is the Stage dropped from the rest */
   Thrust   *  thrust;           /* sum of all motors or ->motors.tcurve    */
   Fin      *  fins;             /* finfo for stage                         */
   Stage    *  next;             /* next Stage ( From Bottom, Up )          */
   Stage    *  prev;             /* previous Stage ( just burned out )      */
};

struct Rocket                                  /* What is in a rocket */
{
   char     *  name;
   int         nose ;
   double      diameter;
   double      length ;
   Stage    *  stages ;
   Site     *  environ ;
};


struct NoseCones {
    char    * name ;    /* Verbose Nose Cone Name */
    int       form ;    /* M,C&B Formula to Apply */
}
   Noses [ ] =
   {
      "undefined",      1 ,
      "ogive",          1 ,
      "conic",          1 ,
      "elliptic",       2 ,
      "parabolic",      2 ,
      "blunt",          2
   } ;

struct FinShapes {
    char    * name ;    /* Verbose Fin Shape Name */
    int       form ;    /* Enum Data  */
}
   FinShape [ ] =
   {
      "undefined",      0 ,
      "polygonal",      1 ,
      "elliptical",     2 ,
      "parabolic",      3 
   } ;

#define NUMFINTYPE ( sizeof FinShapes / sizeof ( struct FinShape ))

Re: [Rocketworkbench-devel] New additions

[Ray C. <ra...@ro...>]

Hi All:

> Another question, there is somebody who would like to start working on a web page??
Well, since I'm not really a programmer, I'll begin work on a webpage to
support the project.

Look for a skeleton to come up at the aRocket site in the next few days
at: http://www.arocket.net/software/dev

What update cycle and information does the Rocket Workbench website need?

So far, I have identified the following requirements, additional
suggestions are appreciated.

Description of project
pointer to mailing list, instructions for joining
pointer to  cvs, instructions for using
e-mail address of point of contact


Ray

[Rocketworkbench-devel] New additions

[Antoine L. <an...@st...>]

Hello,

I have finish implementing a first version of the Runge-Kutta method for solving edo. I is a simple fixed step method. I have include it in libnum.c.

Normally libsimulation should compile under windoze. You need libnum for the Runge-Kutta method. 

Mark, would you like to take a look at that, I think you will find a lot of thing to improve. My C/C++ style are not as clean as a would like it to be. I never study computer science, I'm in mechanical engineering...

Another question, there is somebody who would like to start working on a web page??


-- 
Antoine Lefebvre
ant...@po...

[Rocketworkbench-devel] Runge-Kutta

[Antoine L. <an...@st...>]

Hello,

I am looking for C library implementing the Runge-Kutta method for solving systems of EDO of the first order.

Any idea?

I have only found fortran source.

I will begin to write this solver for the flight simulation program. I will put code in libnum when it will be done. I somebody want to help, you are welcome.

-- 
Antoine Lefebvre
ant...@po...