[DaSh]

Hello Fellow-FOAMers,

I am currently working on a setup for LES of a Taylor Couette flow. To test my setup and mesh, I start out with a laminar simulation (turbulence properties set to laminar).

I want to create both laminar couette flow and laminar taylor vortex flow. I use a setup with eta = 0.5, so I have a critical Reynoldsnumber of about 78.

The problem is, that I can see vortices on both ends of the cylinder for Reynolds = 50 (smaller than Re_crit) by visualising the y-compinents of velocitiy, like this:



Of course for laminar couette flow, there should be no velocities in y-direction.

I use icoFoam as laminar solver. Boundary conditions for p are all zeroGradient for innerWall outerWall and upper and lower end. For U all are fixedValue ( 0 0 0 ), just innerWall is

rotatingWallVelocity
origing (0 0 0)
axis (0 1 0)
omega 0.004; (rad/s, which leads to 0.002 m/s and Re = 50; viscosity 2e-5)


Has anybody got an idea how to improve the setup, or why i get these vortices at low Re? Maybe cyclic BC at top and bottom are necessary?

I am grateful for any kind of help!

Regards,
DaSh

[DaSh]

I have tried cyclic BC and symmetryPlane BC, which produces even worse results concerning velocity in y-direction.

Has somebody got an idea, why I see y-Velocity (v) in laminar case with Re smaller Re_crit?

Thanks in advance!

Danesh

[Lisandro Maders]

Originally Posted by DaSh

I have tried cyclic BC and symmetryPlane BC, which produces even worse results concerning velocity in y-direction.

Has somebody got an idea, why I see y-Velocity (v) in laminar case with Re smaller Re_crit?

Thanks in advance!

Danesh

Hello Danesh,

did you sort this out? I am getting Uy values for laminar Couette flow as well using simpleFoam solver..

And also why did you use "rotatingWallVelocity" on inlet BC?

Regards,

Lisandro