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S. KRISHNAN October 8, 2008 21:02

Rotating Domain
 
Hi all,

Can anyone help me to solve the following problem? It is related to one of a rotating domain. It is a cylindrical reservoir which contains certain liquid. The cylinder is rotating at 3000rpm. When the reservoir rotates about its axis, the liquid goes out through the orifice. Here I want to find out the flow rate and time required to empty the reservoir.

My doubt is which user mode to be selected? General or Turbo?

Also, should I create both solid and fluid domains? Or fluid domain only?

Earlier I tried solving it by creating only the fluid domain (a cylindrical volume with an orifice imprinted on its outer diameter) in the general mode by setting the boundary conditions as: 1. Outer surface and two side walls as: wall-rotating with no mesh motion 2. inner surface as : wall - moving mesh 3. Orifice: output-subsonic with cylindrical vel components only in radial and theta directions. This was in steady state. The calculated flow rate was convincing. But it is observed that the flow rate changes with the output boundary condition. Which boundary condition is ideal for this problem? Like static pressure, output vel components… We can calculate the pressure at a point in the orifice, can we use it as boundary condition? AlsoI want to simulate the transient condition i.e. the inner surface of liquid move towards the outer as the fluid goes out of the domain with respect to time. I tried to give an equation for the mesh motion (inner wall) derived from the time related volume flow. But it gives error message.

Kindly guide me in the proper direction. Waiting to hear from you.



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