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atulverma May 7, 2009 16:04

Solidification drag coefficient
I wanted to know how to calculate solidification drag coefficient(TSDRG),
one can see in the THEORY >AUXILIARY MODELS >Porous Media Models >Solidification Drag Model, that the drag coefficient(K) is defined as a function of fs and TSDRG and in the validation model for segregation in Examples the coefficient is taken to be 2000.
I want to know in which form does it comes in to momentum equation so that it can be used for other alloys also,because people have different ways of invoking the drag model(porous media) given by Darcy(if i am correct) and some versions include viscosity in drag coefficient just like the paper by Voller,Brent,Prakash(1989) for which the segregation model of Flow3d has been validated and others include only the parameter depending on the Denditric arm spacing.
Voller,Brent,Prakash (1989) have used the value as 2e+06 and Flow3d uses 2000 so the differece is due to use of viscosity or density or both?

atulverma May 14, 2009 09:24

I got the answer from the Flow3d support,the formulation tells that the term is divided by density therefore value 2000 taken for validation of Vollers paper is correct.

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