# bounding velocity

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 August 16, 2011, 16:27 bounding velocity #1 Member   Farshad Join Date: Oct 2010 Posts: 76 Rep Power: 8 Sponsored Links Hi, I want to bound my velocity by the following commands: volScalarField ux=U.component(0); volScalarField uy=U.component(1); volScalarField uz=U.component(2); ux.max(5); uy.max(10); uz.max(0); but when i monitor min/max of my velocity i see: (18.58 27.6014 2.57e-15) please tell me why openfoam does not obey my codes! Kind Regards, Farshad

 August 16, 2011, 21:39 #2 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 forAll (U,celli){ U[celli].x()=max( U[celli].x() ,5); ... }

 August 17, 2011, 05:48 problem remains #3 Member   Farshad Join Date: Oct 2010 Posts: 76 Rep Power: 8 Hi, Thanks for the code but velocity is still too high at some points inside domain and my problem still remains. Thanks, Farshad

 August 17, 2011, 14:46 #4 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 dear farshad where do u add this code in your solver? maybe U rewrite again! so change the position of code for example put in pEqn.H

 August 27, 2011, 08:54 bounding problem #5 Member   Farshad Join Date: Oct 2010 Posts: 76 Rep Power: 8 Dear Nima, I put the code in many places to see if it works but the maximum velocity is still 18 that shoud be 9m/s . If i dont extend the bounded region i would have the continuity problem and it does not converge. The interesting thing is if i solve energy equation coupled with momentum equation i get less continuity problems.(maybe because of huge grad(p) in momentum equation) Thanks, Farshad

 August 29, 2011, 17:01 #6 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,216 Blog Entries: 1 Rep Power: 17 hi dear farshad its some how sensible! when you bound the velocity!!! you will encounter continuity problem!!! if you want to reduce maximum velocity maybe you need change ur boundary condition, ur initial condition, even ur mesh size and ur mesh type!

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