dp/dx and dp/dy in Comsol

Hello,

I am working with a N.S equation. Does anybody know that p in N.S equation is static pressure or not?
How can I find out that dp/dx=0 or dp/dy=0 in my simulation?

Comsol bring out p as a dependant variable, but why don't we have gradient of p?

we have u,v,spf U. how about pressure??

Thanks