Setup Reynolds number channel flow
Dear all,
I would like to know what is the general approach to impose a Reynolds number in a simulation of a channel flow with periodicity in the streamwise direction. I understand you have to consider a source term in the momentum equation which is given by friction forces, but how can I estimate this term? Besides, should I start the simulation from a stagnated field (zero velocity) or would it be better to impose a velocity close to the target velocity (the one giving the Re I want)? Any advise to help me to start this experiment is highly appreciated. Thanks in advance |
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the source term can be expressed both in term of a pressure gradient and a mass flow. In the first case you can think of a constant gradient equivalent to the one you have in a Poiseuille flow. The additional pressure fluctuation is solved then by the elliptic equation. |
Thanks for your quick reply.
So what you mean is basically to run an initial simulation to get a Poiseuille flow at the target Reynolds and then to impose that pressure gradient as source term in the next simulation, is it right? |
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The value of the pressure gradient is different between the laminar and turbulent cases (in order to achieve the same mass flow). Check this reference:
http://www.lamc.ing.unibo.it/aimeta2.../MEM-273-0.pdf |
Oh excellent!
Thank you very much |
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