hi,everyone,

I want to know if I let the value of the speed in time layer t=k-1(k is the time layer) equal to zero(or other constant value) in the begainning of the simulation to evaluate the velocity field t=k+1,what will happen?I use the projection-2 method for the imcompressible fluid,and du/dt is differenced by {3u(k+1)-4u(k)+u(k-1)}/{2*delta(t)}.

Tony

If the velocity field is constant and agree with the boundary conditions, then it is already divergence free.

Since you use Gear scheme's, I suppose your problem is transient. it must come with a suitable initial solution which depends on the problem that as to be solved.

If you want more info on projection methods, you might try this location:

http://www.math.psu.edu/shen/publications.html