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Microfluidic pipe outlet with free velocity profile?

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Hello everyone,

I am modeling the flow within a microfluidic system, let's just say it is a straight pipe for the purposes of the question. The direction of the flow could be towards either side of the pipe. I set the velocity/pressure at the inlet, and record flow in the outlet. The outlet flow should be fully developed when flow is from the inlet to the outlet (pipe length > entrance length), but it should be completely undeveloped when the flow is from the outlet to the inlet (outlet is the true entrance to pipe). Everything I have tried gives me only a fully developed flow, no regardless of the direction of the flow.

Is there a way to have the outlet flow be either developed/undeveloped depending on the circumstance? I am currently running separate stationary simulations, but eventually I will run a single time-dependent where the flow direction will fluctuate, so ideally the fix would be the same for both flow directions.

Thank you, Christos

0 Replies Last Post Mar 8, 2020, 5:46 PM EDT
COMSOL Moderator

Hello Christos Michas

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