Does recirculation zone present in laminar flow?

swindlers · May 11, 2024, 06:43

I am trying to model a 2D rayleigh step bearing.The wall with a step is stationary and straight one is moving. Pressures are identical at the inlet and outlet so flow is friction driven and its direction is from wide channel to the narrow channel.

Flow Geometry:

dsgsd.png

What I am asking is, the flow is definitely laminar in both wide and narrow channels (Re=100-500). However, because of the step there will be recirculation zone and flow seperation zone.

I was planning to use laminar viscous model in CFD but I am in doubt. Can recirculation zone also present in laminar flow? Can laminar viscous model capture the physics in the near-wall region of recirculation zones?

Thanks in advance

FMDenaro · May 11, 2024, 13:53

There are a lot of case of laminar flows with recirculation. At low Re number you can simulate your flow problem without turbulence models. However, the real physics could be 3d.
In any case, you need a grid that resolved the BLz

May 11, 2024, 06:43	Does recirculation zone present in laminar flow?	#1
swindlers New Member Görkem Join Date: Nov 2022 Posts: 2 Rep Power: 0	I am trying to model a 2D rayleigh step bearing.The wall with a step is stationary and straight one is moving. Pressures are identical at the inlet and outlet so flow is friction driven and its direction is from wide channel to the narrow channel. Flow Geometry: dsgsd.png What I am asking is, the flow is definitely laminar in both wide and narrow channels (Re=100-500). However, because of the step there will be recirculation zone and flow seperation zone. I was planning to use laminar viscous model in CFD but I am in doubt. Can recirculation zone also present in laminar flow? Can laminar viscous model capture the physics in the near-wall region of recirculation zones? Thanks in advance

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May 11, 2024, 13:53		#2
FMDenaro Senior Member Filippo Maria Denaro Join Date: Jul 2010 Posts: 6,982 Rep Power: 73	There are a lot of case of laminar flows with recirculation. At low Re number you can simulate your flow problem without turbulence models. However, the real physics could be 3d. In any case, you need a grid that resolved the BLz