I am working on a finite difference model for the cavity flow in which the top lid is moving. I have the model developed and solved for one iteration. I set the initial vorticity and stream function to zero, except at the top, which is the lid velocity. That yields an initial vorticity matrix of all zeros except the top row, which is equal to my lid velocity - is that correct?

thanks

I meant to say I set the velocity and stream function to zero except the lid

It is correct. The flow is driven the moving lid and after one iteration there wont be significant change in the interior flow field. Why dont you check it after 50 or 100 time steps ?

dear Andrew u must but the following boundary conditions 1- at all walls stream function=0 except at the upper=U*H,where U is the moving lid velocity and H is the cavity height 2-the vorticity must be calculated during iteration from nabla square (psi)=-omega refer to the foloowing reference for obtain the vorticity at the wall i-computational fluid dynamics for engineers-vol.1 by Hoffmann and Chiang 1993 ii-computational fluid mechanics and heat transfer ,Anderson et al. 1984-Mac-Graw Hill

have a good luck Khairy-Egypt