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August 1, 2018, 11:31 |
Channel Flow with Constant Mass Flow Rate
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New Member
Buzz
Join Date: Apr 2018
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I am trying to simulate a channel flow of infinite stream-wise length, fixing a constant mass flow rate across the channel to drive the flow. I am using simpleFoam with kw SST turbulence model. My strategy is to set a periodic boundary condition at the inlet and outlet for U, nut, k and w (to give the effect of an infinite stream-wise length) and allow the pressure to be solved (to ensure a fixed mass flow rate). I am using OF version 1.7.1.
I tried to set a cyclic boundary condition for the inlet and outlet in the blockmesh dictionary file, however this meant that the simulation would not run unless I set the inlet/outlet boundary condition for every flow variable as cyclic in the field files (I do not want to do this for pressure). Following this, my approach was to use the mappedPatch in the blockmesh dictionary file as follows: Code:
boundary ( inlet { type mappedPatch; sampleMode nearestPatchFace; samplePatch outlet; faces ((7 4 0 3)); } outlet { type patch; faces ((2 1 5 6)); U: Code:
boundaryField { inlet { type mapped; value uniform (10 0 0 ); setAverage true; average (10 0 0); } outlet { type zeroGradient; } Code:
boundaryField { inlet { type zeroGradient; } outlet { type zeroGradient; } Code:
boundaryField { inlet { type mapped; value uniform 200000; setAverage false; average 200000; } outlet { type zeroGradient; } Code:
boundaryField { inlet { type mapped; value uniform 0.002; setAverage false; average 0.002; } outlet { type zeroGradient; } Code:
boundaryField { inlet { type mapped; value uniform 0; setAverage false; average 0; } outlet { type zeroGradient; } -Do these boundary conditions make sense for what I am trying to achieve? -What is the function of "sampleMode" and "samplePatch" entries (sampleMode is required when using mappedPatch type)? -I have read that the mass flow rate is fixed through setting "true" for the "setAverage" entry in the "U" field file. Is this correct? Thanks |
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boundary condition, channel, mapped, mass flow rate |
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