linear solver failure when using SST model

fanzhong Meng

I do a quasi-3D airfoil simlation, and I had generate one element(2mm) 3D grid. when i use SST model to calculate, I always get the follow error message after several steps of iteration.

ERROR #004100018 has occurred in subroutine FINMES.

Message: | Fatal overflow in linear solver. I found that the "wallscale" variable can not converge. but other variable, such as velocity mass and k and W, can converge. I don't know why. Does it have something with the grid quality? The largest width-height ratio of my gird may be 400. That is because I have made a very fine grid near the wall (0.04mm),so this will contribute to large width-height ratio in some position.

can anyone give me some suggestion? thanks a lot .