## Re: [Gfs-users] GfsRiver

 Re: [Gfs-users] GfsRiver From: joerg robl - 2010-12-23 10:04:43 ```Dear Pierre-Yves, Thank you for your response. Step by step I get my feet on the ground. > > As first test, I solved the 1D case so that there is only an x, but we can > define q=(qx,qy) and go in 2D. > Yes, sure! It's always a good idea to start with the most simple case. I don't speak French so I had some problems reading Fig. 5. However, I should have seen that it is 1D. Nevertheless, I can't see how to correctly implement q=(qx,qy). Can you give me a hint? cheers Joerg 2010/12/22 "Pierre-Yves Lagrée (PYL)" : > Dear Jorg > > As a long term goal it would be great to get an erosion law based on > the basal shear stress of the river and a function that describes the > transport capacity of the fluid. > > Good program ;-) > > (1) calculate the gradient of the velocity in x-direction at every > time step. {Shouldn't this be the flow direction? or should'nt we use > dx and dy} > > As first test, I solved the 1D case so that there is only an x, but we can > define q=(qx,qy) and go in 2D. > > > (2) update the topography ever 10th timestep based on Zb - 0.1*dt*dqdx > {Why not every time step?} > > just a trick to disconnect the flow and the bed changes. It gives time to > waves to go outside the domain without eroding the soil. > >    In the case that the velocity increases sediment is removed from the bed >    In the case that the velocity decreases sediment is deposited > > This sounds correct, > > I forgot the mention that we should take the gradients in the stream > power rather than the gradients in the velocity. > > OK, the taking q=U is the order 0 of an erosion model. Why not the stream > power. > My preference will be an improved model of the skin friction. > > If it is ok for you I will try to implement this approach to my Gerris > Parameter File. > > good! I confess that I have no time this end of year! > > Sincerely > > all the best > Joerg > > > > > > > > 2010/12/22 "Pierre-Yves Lagrée (PYL)" : > > Dear Jorg > > Has anybody tried to simulate erosion / deposition using  GfsRiver? > > Any suggestions? > > This is a real hot topic, which interests me as well, I have succeed to > > implement a crude model like of a flux of material proportional to the > > velocity > >      Init { istep = 1 } { > >       sU2 = Velocity > >       dqdx = dx("sU2") > >     } > > and an update of the soil like > >    Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. > > an example is on the draft figure 5 > > http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf > > What are your plans? > > cheers > > > > cheers Joerg > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > > ---> Pierre-Yves Lagrée (PYL) > > -->www.lmm.jussieu.fr/~lagree > > -> pierre-yves.lagree@... > > _____________________________ > > ///////////////////////////// > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months.  Over 3 million businesses have gone Google with Google > Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > ---> Pierre-Yves Lagrée (PYL) > -->www.lmm.jussieu.fr/~lagree > -> pierre-yves.lagree@... > _____________________________ > ///////////////////////////// > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months.  Over 3 million businesses have gone Google with Google > Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ```

 [Gfs-users] GfsRiver From: joerg robl - 2010-12-22 10:54:17 ```Dear GERRIS Gurus! (1) During the last week(s) I made my way thru the Karamea tutorial. I'm really impressed by the code although I've just seen a glimpse of all possibilities. I'm extremely keen to train my GERRIS skills. At the moment I'm interested in the maximum values for the velocity and the flow depth of a river over time. I wonder if there is an object like EventSum to implement that into the GERRIS parameter file. (2) Has anybody tried to simulate erosion / deposition using GfsRiver? Any suggestions? cheers Joerg ```
 Re: [Gfs-users] GfsRiver From: Pierre-Yves Lagrée (PYL) - 2010-12-22 11:12:58 Attachments: Message as HTML ```Dear Jorg > Has anybody tried to simulate erosion / deposition using GfsRiver? > Any suggestions? This is a real hot topic, which interests me as well, I have succeed to implement a crude model like of a flux of material proportional to the velocity Init { istep = 1 } { sU2 = Velocity dqdx = dx("sU2") } and an update of the soil like Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. an example is on the draft figure 5 http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf What are your plans? cheers > cheers Joerg > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months. Over 3 million businesses have gone Google with Google Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users ----> ----> ----> ----> ----> ---> Pierre-Yves Lagrée (PYL) -->www.lmm.jussieu.fr/~lagree -> pierre-yves.lagree@... _____________________________ ///////////////////////////// ```
 Re: [Gfs-users] GfsRiver From: joerg robl - 2010-12-22 12:43:06 ```Dear Pierre-Yves, I'm quite a newbie driving GERRIS. Hower, I try to model the Velocity/Flowdepth/Overland Flow of some Austrian and German torrents during and after heavy precipitation events. As input data I have a ALS 1m DEM and Hydro graphs. I worked thru the karamea example and applied it to one of "my" torrents. At the moment I struggle to get the maximum Values for the Velocity and FlowDepth. This should be easy with GERRIS but I'm still in the dark. As a long term goal it would be great to get an erosion law based on the basal shear stress of the river and a function that describes the transport capacity of the fluid. At that point the Fluid can not longer transport the sediment, the deposition should start. As I'm not really familiar with the GERRIS syntax please correct me if I understood something wrong. (1) calculate the gradient of the velocity in x-direction at every time step. {Shouldn't this be the flow direction? or should'nt we use dx and dy} (2) update the topography ever 10th timestep based on Zb - 0.1*dt*dqdx {Why not every time step?} In the case that the velocity increases sediment is removed from the bed In the case that the velocity decreases sediment is deposited If it is ok for you I will try to implement this approach to my Gerris Parameter File. all the best Joerg 2010/12/22 "Pierre-Yves Lagrée (PYL)" : > Dear Jorg > > Has anybody tried to simulate erosion / deposition using  GfsRiver? > Any suggestions? > > This is a real hot topic, which interests me as well, I have succeed to > implement a crude model like of a flux of material proportional to the > velocity >      Init { istep = 1 } { >       sU2 = Velocity >       dqdx = dx("sU2") >     } > and an update of the soil like >    Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. > an example is on the draft figure 5 > http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf > > What are your plans? > > cheers > > > > cheers Joerg > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months.  Over 3 million businesses have gone Google with Google > Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > ---> Pierre-Yves Lagrée (PYL) > -->www.lmm.jussieu.fr/~lagree > -> pierre-yves.lagree@... > _____________________________ > ///////////////////////////// > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months.  Over 3 million businesses have gone Google with Google > Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ```
 Re: [Gfs-users] GfsRiver From: joerg robl - 2010-12-22 13:46:23 ```Dear Pierre-Yves, I forgot the mention that we should take the gradients in the stream power rather than the gradients in the velocity. The stream power (s) is described as : s= S*A^n where S represents the channel gradient and A the drainage area (as a proxy for the discharge) and n describes the non-linearity.. We should probably consider the Flowdepth!? Joerg 2010/12/22 joerg robl : > Dear Pierre-Yves, > > I'm quite a newbie driving GERRIS. Hower, I try to model the > Velocity/Flowdepth/Overland Flow of some Austrian and German torrents > during and after heavy precipitation events. As input data I have a > ALS 1m DEM and Hydro graphs. I worked thru the karamea example and > applied it to one of "my" torrents. > > At the moment I struggle to get the maximum Values for the Velocity > and FlowDepth. This should be easy with GERRIS but I'm still in the > dark. > > As a long term goal it would be great to get an erosion law based on > the basal shear stress of the river and a function that describes the > transport capacity of the fluid. At that point the Fluid can not > longer transport the sediment, the deposition should start. > > As I'm not really familiar with the GERRIS syntax please correct me if > I understood something wrong. > > (1) calculate the gradient of the velocity in x-direction at every > time step. {Shouldn't this be the flow direction? or should'nt we use > dx and dy} > > (2) update the topography ever 10th timestep based on Zb - 0.1*dt*dqdx > {Why not every time step?} >    In the case that the velocity increases sediment is removed from the bed >    In the case that the velocity decreases sediment is deposited > > > If it is ok for you I will try to implement this approach to my Gerris > Parameter File. > > all the best > Joerg > > > > > > > > 2010/12/22 "Pierre-Yves Lagrée (PYL)" : >> Dear Jorg >> >> Has anybody tried to simulate erosion / deposition using  GfsRiver? >> Any suggestions? >> >> This is a real hot topic, which interests me as well, I have succeed to >> implement a crude model like of a flux of material proportional to the >> velocity >>      Init { istep = 1 } { >>       sU2 = Velocity >>       dqdx = dx("sU2") >>     } >> and an update of the soil like >>    Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. >> an example is on the draft figure 5 >> http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf >> >> What are your plans? >> >> cheers >> >> >> >> cheers Joerg >> >> ------------------------------------------------------------------------------ >> Forrester recently released a report on the Return on Investment (ROI) of >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> within 7 months.  Over 3 million businesses have gone Google with Google >> Apps: >> an online email calendar, and document program that's accessible from your >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> _______________________________________________ >> Gfs-users mailing list >> Gfs-users@... >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> ----> ----> ----> ----> ----> >> ---> Pierre-Yves Lagrée (PYL) >> -->www.lmm.jussieu.fr/~lagree >> -> pierre-yves.lagree@... >> _____________________________ >> ///////////////////////////// >> >> ------------------------------------------------------------------------------ >> Forrester recently released a report on the Return on Investment (ROI) of >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> within 7 months.  Over 3 million businesses have gone Google with Google >> Apps: >> an online email calendar, and document program that's accessible from your >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> _______________________________________________ >> Gfs-users mailing list >> Gfs-users@... >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> > ```
 Re: [Gfs-users] GfsRiver From: Pierre-Yves Lagrée (PYL) - 2010-12-22 14:40:03 Attachments: Message as HTML ```Dear Jorg > As a long term goal it would be great to get an erosion law based on > the basal shear stress of the river and a function that describes the > transport capacity of the fluid. Good program ;-) > (1) calculate the gradient of the velocity in x-direction at every > time step. {Shouldn't this be the flow direction? or should'nt we use > dx and dy} As first test, I solved the 1D case so that there is only an x, but we can define q=(qx,qy) and go in 2D. > (2) update the topography ever 10th timestep based on Zb - 0.1*dt*dqdx > {Why not every time step?} just a trick to disconnect the flow and the bed changes. It gives time to waves to go outside the domain without eroding the soil. > In the case that the velocity increases sediment is removed from the bed > In the case that the velocity decreases sediment is deposited This sounds correct, > I forgot the mention that we should take the gradients in the stream > power rather than the gradients in the velocity. OK, the taking q=U is the order 0 of an erosion model. Why not the stream power. My preference will be an improved model of the skin friction. > If it is ok for you I will try to implement this approach to my Gerris > Parameter File. good! I confess that I have no time this end of year! Sincerely > all the best > Joerg > > > > > > > > 2010/12/22 "Pierre-Yves Lagrée (PYL)" : >> Dear Jorg >> >> Has anybody tried to simulate erosion / deposition using GfsRiver? >> Any suggestions? >> >> This is a real hot topic, which interests me as well, I have succeed to >> implement a crude model like of a flux of material proportional to the >> velocity >> Init { istep = 1 } { >> sU2 = Velocity >> dqdx = dx("sU2") >> } >> and an update of the soil like >> Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. >> an example is on the draft figure 5 >> http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf >> >> What are your plans? >> >> cheers >> >> >> >> cheers Joerg >> >> ------------------------------------------------------------------------------ >> Forrester recently released a report on the Return on Investment (ROI) of >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> within 7 months. Over 3 million businesses have gone Google with Google >> Apps: >> an online email calendar, and document program that's accessible from your >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> _______________________________________________ >> Gfs-users mailing list >> Gfs-users@... >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> ----> ----> ----> ----> ----> >> ---> Pierre-Yves Lagrée (PYL) >> -->www.lmm.jussieu.fr/~lagree >> -> pierre-yves.lagree@... >> _____________________________ >> ///////////////////////////// >> >> ------------------------------------------------------------------------------ >> Forrester recently released a report on the Return on Investment (ROI) of >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> within 7 months. Over 3 million businesses have gone Google with Google >> Apps: >> an online email calendar, and document program that's accessible from your >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> _______________________________________________ >> Gfs-users mailing list >> Gfs-users@... >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months. Over 3 million businesses have gone Google with Google Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users ----> ----> ----> ----> ----> ---> Pierre-Yves Lagrée (PYL) -->www.lmm.jussieu.fr/~lagree -> pierre-yves.lagree@... _____________________________ ///////////////////////////// ```
 Re: [Gfs-users] GfsRiver From: joerg robl - 2010-12-23 10:04:43 ```Dear Pierre-Yves, Thank you for your response. Step by step I get my feet on the ground. > > As first test, I solved the 1D case so that there is only an x, but we can > define q=(qx,qy) and go in 2D. > Yes, sure! It's always a good idea to start with the most simple case. I don't speak French so I had some problems reading Fig. 5. However, I should have seen that it is 1D. Nevertheless, I can't see how to correctly implement q=(qx,qy). Can you give me a hint? cheers Joerg 2010/12/22 "Pierre-Yves Lagrée (PYL)" : > Dear Jorg > > As a long term goal it would be great to get an erosion law based on > the basal shear stress of the river and a function that describes the > transport capacity of the fluid. > > Good program ;-) > > (1) calculate the gradient of the velocity in x-direction at every > time step. {Shouldn't this be the flow direction? or should'nt we use > dx and dy} > > As first test, I solved the 1D case so that there is only an x, but we can > define q=(qx,qy) and go in 2D. > > > (2) update the topography ever 10th timestep based on Zb - 0.1*dt*dqdx > {Why not every time step?} > > just a trick to disconnect the flow and the bed changes. It gives time to > waves to go outside the domain without eroding the soil. > >    In the case that the velocity increases sediment is removed from the bed >    In the case that the velocity decreases sediment is deposited > > This sounds correct, > > I forgot the mention that we should take the gradients in the stream > power rather than the gradients in the velocity. > > OK, the taking q=U is the order 0 of an erosion model. Why not the stream > power. > My preference will be an improved model of the skin friction. > > If it is ok for you I will try to implement this approach to my Gerris > Parameter File. > > good! I confess that I have no time this end of year! > > Sincerely > > all the best > Joerg > > > > > > > > 2010/12/22 "Pierre-Yves Lagrée (PYL)" : > > Dear Jorg > > Has anybody tried to simulate erosion / deposition using  GfsRiver? > > Any suggestions? > > This is a real hot topic, which interests me as well, I have succeed to > > implement a crude model like of a flux of material proportional to the > > velocity > >      Init { istep = 1 } { > >       sU2 = Velocity > >       dqdx = dx("sU2") > >     } > > and an update of the soil like > >    Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. > > an example is on the draft figure 5 > > http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf > > What are your plans? > > cheers > > > > cheers Joerg > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > > ---> Pierre-Yves Lagrée (PYL) > > -->www.lmm.jussieu.fr/~lagree > > -> pierre-yves.lagree@... > > _____________________________ > > ///////////////////////////// > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months.  Over 3 million businesses have gone Google with Google > Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > ---> Pierre-Yves Lagrée (PYL) > -->www.lmm.jussieu.fr/~lagree > -> pierre-yves.lagree@... > _____________________________ > ///////////////////////////// > > ------------------------------------------------------------------------------ > Forrester recently released a report on the Return on Investment (ROI) of > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > within 7 months.  Over 3 million businesses have gone Google with Google > Apps: > an online email calendar, and document program that's accessible from your > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ```
 Re: [Gfs-users] GfsRiver From: Pierre-Yves Lagrée (PYL) - 2010-12-23 10:18:11 Attachments: Message as HTML ```Hi > Nevertheless, I can't see how to correctly implement q=(qx,qy). Can > you give me a hint? > I did not try, but simply if q is proportional to the velocity and must be in the direction of it: qx=Q*U/Velocity and qy=Q*V/Velocity where Q is your choice of flux function, so the divergence is like divq = dx("qx")+dy("qy") - note that I started after a while (again to wait a "steady" state Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*divq} - note that I did not mention you that in the 1D case I can put a slope correction to the flux: df = dx("Zb") dqdx = dx("sU2") - 0.1*dx("df") cheers > cheers > Joerg > > > > > > > 2010/12/22 "Pierre-Yves Lagrée (PYL)" : >> Dear Jorg >> >> As a long term goal it would be great to get an erosion law based on >> the basal shear stress of the river and a function that describes the >> transport capacity of the fluid. >> >> Good program ;-) >> >> (1) calculate the gradient of the velocity in x-direction at every >> time step. {Shouldn't this be the flow direction? or should'nt we use >> dx and dy} >> >> As first test, I solved the 1D case so that there is only an x, but we can >> define q=(qx,qy) and go in 2D. >> >> >> (2) update the topography ever 10th timestep based on Zb - 0.1*dt*dqdx >> {Why not every time step?} >> >> just a trick to disconnect the flow and the bed changes. It gives time to >> waves to go outside the domain without eroding the soil. >> >> In the case that the velocity increases sediment is removed from the bed >> In the case that the velocity decreases sediment is deposited >> >> This sounds correct, >> >> I forgot the mention that we should take the gradients in the stream >> power rather than the gradients in the velocity. >> >> OK, the taking q=U is the order 0 of an erosion model. Why not the stream >> power. >> My preference will be an improved model of the skin friction. >> >> If it is ok for you I will try to implement this approach to my Gerris >> Parameter File. >> >> good! I confess that I have no time this end of year! >> >> Sincerely >> >> all the best >> Joerg >> >> >> >> >> >> >> >> 2010/12/22 "Pierre-Yves Lagrée (PYL)" : >> >> Dear Jorg >> >> Has anybody tried to simulate erosion / deposition using GfsRiver? >> >> Any suggestions? >> >> This is a real hot topic, which interests me as well, I have succeed to >> >> implement a crude model like of a flux of material proportional to the >> >> velocity >> >> Init { istep = 1 } { >> >> sU2 = Velocity >> >> dqdx = dx("sU2") >> >> } >> >> and an update of the soil like >> >> Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. >> >> an example is on the draft figure 5 >> >> http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf >> >> What are your plans? >> >> cheers >> >> >> >> cheers Joerg >> >> ------------------------------------------------------------------------------ >> >> Forrester recently released a report on the Return on Investment (ROI) of >> >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> >> within 7 months. Over 3 million businesses have gone Google with Google >> >> Apps: >> >> an online email calendar, and document program that's accessible from your >> >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> >> _______________________________________________ >> >> Gfs-users mailing list >> >> Gfs-users@... >> >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> ----> ----> ----> ----> ----> >> >> ---> Pierre-Yves Lagrée (PYL) >> >> -->www.lmm.jussieu.fr/~lagree >> >> -> pierre-yves.lagree@... >> >> _____________________________ >> >> ///////////////////////////// >> >> ------------------------------------------------------------------------------ >> >> Forrester recently released a report on the Return on Investment (ROI) of >> >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> >> within 7 months. Over 3 million businesses have gone Google with Google >> >> Apps: >> >> an online email calendar, and document program that's accessible from your >> >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> >> _______________________________________________ >> >> Gfs-users mailing list >> >> Gfs-users@... >> >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> >> >> ------------------------------------------------------------------------------ >> Forrester recently released a report on the Return on Investment (ROI) of >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> within 7 months. Over 3 million businesses have gone Google with Google >> Apps: >> an online email calendar, and document program that's accessible from your >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> _______________________________________________ >> Gfs-users mailing list >> Gfs-users@... >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> ----> ----> ----> ----> ----> >> ---> Pierre-Yves Lagrée (PYL) >> -->www.lmm.jussieu.fr/~lagree >> -> pierre-yves.lagree@... >> _____________________________ >> ///////////////////////////// >> >> ------------------------------------------------------------------------------ >> Forrester recently released a report on the Return on Investment (ROI) of >> Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even >> within 7 months. Over 3 million businesses have gone Google with Google >> Apps: >> an online email calendar, and document program that's accessible from your >> browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew >> _______________________________________________ >> Gfs-users mailing list >> Gfs-users@... >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> > > ------------------------------------------------------------------------------ > Learn how Oracle Real Application Clusters (RAC) One Node allows customers > to consolidate database storage, standardize their database environment, and, > should the need arise, upgrade to a full multi-node Oracle RAC database > without downtime or disruption > http://p.sf.net/sfu/oracle-sfdevnl > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users ----> ----> ----> ----> ----> ---> Pierre-Yves Lagrée (PYL) -->www.lmm.jussieu.fr/~lagree -> pierre-yves.lagree@... _____________________________ ///////////////////////////// ```
 Re: [Gfs-users] GfsRiver From: joerg robl - 2010-12-23 10:47:14 ```Dear Pierre-Yves, Thank you so much! I will play a little bit with your suggested solution. Beside of that I might have a really interesting example to test your "more sophisticated" erosion/deposition function you are working on. I can send you ALS data of a torrent before and after a debris flow event. In this case the erosion/ deposition have been directly measured in field. all the best merry X-mas GERRIS is really GREAT! 2010/12/23 "Pierre-Yves Lagrée (PYL)" : > Hi > > Nevertheless, I can't see how to correctly implement q=(qx,qy). Can > you give me a hint? > > > > I did not try, but simply if q is proportional to the velocity and must be > in the direction of it: > qx=Q*U/Velocity  and qy=Q*V/Velocity > where Q is your choice of flux function, so the divergence is like > >       divq = dx("qx")+dy("qy") > > - note that I started after a while (again to wait a "steady" state >     Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*divq} > - note that I did not mention you that in the 1D case I can put  a slope > correction to the flux: >       df = dx("Zb") >       dqdx = dx("sU2") - 0.1*dx("df") > cheers > > > cheers > Joerg > > > > > > > 2010/12/22 "Pierre-Yves Lagrée (PYL)" : > > Dear Jorg > > As a long term goal it would be great to get an erosion law based on > > the basal shear stress of the river and a function that describes the > > transport capacity of the fluid. > > Good program ;-) > > (1) calculate the gradient of the velocity in x-direction at every > > time step. {Shouldn't this be the flow direction? or should'nt we use > > dx and dy} > > As first test, I solved the 1D case so that there is only an x, but we can > > define q=(qx,qy) and go in 2D. > > > (2) update the topography ever 10th timestep based on Zb - 0.1*dt*dqdx > > {Why not every time step?} > > just a trick to disconnect the flow and the bed changes. It gives time to > > waves to go outside the domain without eroding the soil. > >    In the case that the velocity increases sediment is removed from the bed > >    In the case that the velocity decreases sediment is deposited > > This sounds correct, > > I forgot the mention that we should take the gradients in the stream > > power rather than the gradients in the velocity. > > OK, the taking q=U is the order 0 of an erosion model. Why not the stream > > power. > > My preference will be an improved model of the skin friction. > > If it is ok for you I will try to implement this approach to my Gerris > > Parameter File. > > good! I confess that I have no time this end of year! > > Sincerely > > all the best > > Joerg > > > > > > > > 2010/12/22 "Pierre-Yves Lagrée (PYL)" : > > Dear Jorg > > Has anybody tried to simulate erosion / deposition using  GfsRiver? > > Any suggestions? > > This is a real hot topic, which interests me as well, I have succeed to > > implement a crude model like of a flux of material proportional to the > > velocity > >      Init { istep = 1 } { > >       sU2 = Velocity > >       dqdx = dx("sU2") > >     } > > and an update of the soil like > >    Init {start = 5 istep = 10 } { Zb = Zb - 0.1*dt*dqdx}. > > an example is on the draft figure 5 > > http://www.lmm.jussieu.fr/~lagree/SOURCES/GERRIS/STVENANT/dune_SV.pdf > > What are your plans? > > cheers > > > > cheers Joerg > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > > ---> Pierre-Yves Lagrée (PYL) > > -->www.lmm.jussieu.fr/~lagree > > -> pierre-yves.lagree@... > > _____________________________ > > ///////////////////////////// > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > > ---> Pierre-Yves Lagrée (PYL) > > -->www.lmm.jussieu.fr/~lagree > > -> pierre-yves.lagree@... > > _____________________________ > > ///////////////////////////// > > ------------------------------------------------------------------------------ > > Forrester recently released a report on the Return on Investment (ROI) of > > Google Apps. They found a 300% ROI, 38%-56% cost savings, and break-even > > within 7 months.  Over 3 million businesses have gone Google with Google > > Apps: > > an online email calendar, and document program that's accessible from your > > browser. Read the Forrester report: http://p.sf.net/sfu/googleapps-sfnew > > _______________________________________________ > > Gfs-users mailing list > > Gfs-users@... > > https://lists.sourceforge.net/lists/listinfo/gfs-users > > > > ------------------------------------------------------------------------------ > Learn how Oracle Real Application Clusters (RAC) One Node allows customers > to consolidate database storage, standardize their database environment, > and, > should the need arise, upgrade to a full multi-node Oracle RAC database > without downtime or disruption > http://p.sf.net/sfu/oracle-sfdevnl > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ----> ----> ----> ----> ----> > ---> Pierre-Yves Lagrée (PYL) > -->www.lmm.jussieu.fr/~lagree > -> pierre-yves.lagree@... > _____________________________ > ///////////////////////////// > > ------------------------------------------------------------------------------ > Learn how Oracle Real Application Clusters (RAC) One Node allows customers > to consolidate database storage, standardize their database environment, > and, > should the need arise, upgrade to a full multi-node Oracle RAC database > without downtime or disruption > http://p.sf.net/sfu/oracle-sfdevnl > _______________________________________________ > Gfs-users mailing list > Gfs-users@... > https://lists.sourceforge.net/lists/listinfo/gfs-users > > ```