is this tetra cell too distorted? How do you relate the solver math to this (how did you get this insight?)?I'm still developing my skills.. Does having this tet cell cause a problem in the interpolation? Can you please enlighten me more?

I made this part around the ball in order to have the boundary layer moving with the ball. Is it causing a problem? Do you think I should change the method?

By decreasing the time step, I have the negative cell error but the valve has moved almost to the opening
I'm sorry to ask you so many questions but you are my only hope