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brown October 2, 2007 02:43

rotating bucket problem
I am trying to validate a free surface modeling code (in CFX 11) for a rotating bucket problem.

I have taken the dia of the cylindrical bucket to be 5 cm and the total height is 10 cm. I have taken the height of water in the bucket at 7 cm. I have different values of rotation speeds at 1 rev/min and 10 rev/min.

I ran the simulation as follows.Homogenous model for multiphase flow.for heat transfer model,i gave Isothermal(25 C).For interpahse transfer I used Mixture model. If I do not consider buoyancy the simulations converge,but if i do,they do not.

I am not sure if the converged results are physically acceptable,becoz even at small speeds the free surface vertex is near the bottom of the vessel.

I am alos not sure if buoyancy can be so conviniently neglected in free surface flows.!!

SOme tips in this regard will be appreciated..

Thanks a ton,in advance, Brown..

Glenn Horrocks October 2, 2007 18:44

Re: rotating bucket problem
What do you mean "Buoyancy can be .. neglected in free surface flows"? Buoyancy is what makes water go down and air go up so for many flows it cannot be neglected.

Glenn Horrocks

brown. October 3, 2007 01:13

Re: rotating bucket problem
dear glenn

am aware of the fact you mentioned in the reply to my query.. but i hav seen in cfx help documentation that when buoyancy is enabled the total pressure will no longer have the hydrostatic pressure..

am using expression for hydrostatic pressure..datsy am asking whether it makes any difference if i enable buoyancy again..


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