How to set transient velocity inlet bc

LijieNPIC · September 3, 2011, 10:39

Hi, foamers

Now I have a problem and need your help. I want to simulate spatial developing pipe flow and heat transfer by DNS. So first I performed fully developed pipe flow with DNS. And now I want to set the inlet velocity bc with transient outlet velocity of the fully pipe flow. I don't know how to do it.

I searched the forum and found some related thread:
timeVaryFlowRateInletVelocity bc and set time varying flowrate, but the velocity distribution cannot be changed.
groovBC utility can set velocity distribution, but the distribution should be a function

So I need your help. Thanks in advance!

nimasam · September 4, 2011, 11:43

as a suggestion you can use two blocks and make the first block long enough to reach the fully developed solution then using cyclic boundary condition between to block patches and then in ur second block ur inlet is fully developed!!!!
but if ur inlet and out let have the same mesh, you can easily do it manually!!! just you need to change the patches name in ur dictionary!!! or copy the nonuniform value at outlet into ur inlet in time zero!!!

September 3, 2011, 10:39	How to set transient velocity inlet bc	#1
LijieNPIC New Member Join Date: Oct 2010 Posts: 24 Rep Power: 15	Hi, foamers Now I have a problem and need your help. I want to simulate spatial developing pipe flow and heat transfer by DNS. So first I performed fully developed pipe flow with DNS. And now I want to set the inlet velocity bc with transient outlet velocity of the fully pipe flow. I don't know how to do it. I searched the forum and found some related thread: timeVaryFlowRateInletVelocity bc and set time varying flowrate, but the velocity distribution cannot be changed. groovBC utility can set velocity distribution, but the distribution should be a function So I need your help. Thanks in advance!

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September 4, 2011, 11:43		#2
nimasam Senior Member Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,266 Blog Entries: 1 Rep Power: 24	as a suggestion you can use two blocks and make the first block long enough to reach the fully developed solution then using cyclic boundary condition between to block patches and then in ur second block ur inlet is fully developed!!!! but if ur inlet and out let have the same mesh, you can easily do it manually!!! just you need to change the patches name in ur dictionary!!! or copy the nonuniform value at outlet into ur inlet in time zero!!!