Hallo. I am trying to simulate flow in 2D-coaxial cylinders i.e. annular rotating flow. patching the domain with air and water is easy but i couldnt provide different rotating velocities (as initial condition) to the two fluid.Is it possible to do it?

Note: my case is not axisymmetric.

Thanks

Solve -> Initialize -> Patch

Under Phase select your desired phase and under Variable you should be able to select Radial velocity. Select appropriate zone or register and input your value.

Don't you patch volume fraction in similar way?

Thanks for ur reply but unfortunately its not that easy. With VOF 2D-analysis, the only available variable for patching is Volume fraction. I dont see any option for velocity. The velocity only appear if i want to run an axisymmetric or axisymmetric swirl flow which is not the case. According to help files i have read, i can conclude thats its only possible in 3D?

Note: I want to initialize the field with circumferential velocity (i.e. theta velocity in cylinderical coordinates)and not radial veloctiy.

Thanks for ur reply but unfortunately its not that easy. With VOF 2D-analysis, the only available variable for patching is Volume fraction. I dont see any option for velocity. The velocity only appear if i want to run an axisymmetric or axisymmetric swirl flow which is not the case. According to help files i have read, i can conclude thats its only possible in 3D?

Note: I want to initialize the field with circumferential velocity (i.e. theta velocity in cylinderical coordinates)and not radial veloctiy.

Hi,

Define the fluid zone in two separate fluid zones during meshing. Then you can give rotational speed for each fluid zones using multiple reference frame method in boundary condition panel.

I am not sure how much compatability of MRF with VOF model.

with warm regards, JSM