Solidification problem: viscosity ratio limited

Deepak

hi, I am modeling a continuous casting problem using solidification model in FLUENT. The case is 2d,unsteady and the domain is a rectangle with solid being pulled out of the domain. when i start iterating, after many time steps i get the message turbulent viscosity ratio limited in xxx cells. They tend to get limited in the cells near the area of interest, the solidification front. Also the appear only on the solid side of the front!. I m confused, do they have any meaning on the solid side? Also after many time steps they tend to distort the solidification front.

I have tried many methods that i found in this forum, i specified the boundary conditions turbulent parameters according to the eqn I=0.16*Re^(-0.125). Also i specified the initial values of k and epsilon according to the eqns k= 1.5*(UI)^2 and epsilon = (cmu^0.75*k^1.5)/l but it didn make any difference.

I also tried solving the laminar case first, then based on that i solved for the turbulence quantities and then switched on the momentum and energy eqns. still it didn work

can anyone tell me how i should deal with this problem?

any help will be greatly appreciated