Re: [Gfs-users] GfsRiver
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From: Pierre-Yves L. (PYL) <pie...@up...> - 2010-12-23 10:18:11
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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)" <pie...@up...>: >> 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)" <pie...@up...>: >> >> 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...@li... >> >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> ----> ----> ----> ----> ----> >> >> ---> Pierre-Yves Lagrée (PYL) >> >> -->www.lmm.jussieu.fr/~lagree >> >> -> pie...@up... >> >> _____________________________ >> >> ///////////////////////////// >> >> ------------------------------------------------------------------------------ >> >> 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...@li... >> >> 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...@li... >> https://lists.sourceforge.net/lists/listinfo/gfs-users >> >> ----> ----> ----> ----> ----> >> ---> Pierre-Yves Lagrée (PYL) >> -->www.lmm.jussieu.fr/~lagree >> -> pie...@up... >> _____________________________ >> ///////////////////////////// >> >> ------------------------------------------------------------------------------ >> 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...@li... >> 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...@li... > https://lists.sourceforge.net/lists/listinfo/gfs-users ----> ----> ----> ----> ----> ---> Pierre-Yves Lagrée (PYL) -->www.lmm.jussieu.fr/~lagree -> pie...@up... _____________________________ ///////////////////////////// |