[coops]

Hi all,

I am trying to set up a model that requires hydrostatic equilibirum (essentially the pressure force needs to exactly balance the force from gravity, this is done by dp/dz = -p_0*H, where p_0 is the initial pressure field and H is a constant number (in our case) called the scale height). When I try to impliment a simple version of this I am able to create a pressure field that has the desired distribution but and I try to balance this with a gravitational acceleration but I still don't have it in equilibrium. I have played around with a few factors and now I think it may be that the pressure that I have specifed (i have created a pressure field that assigns a value to the center of the cells) is slighty out of sink with the gradient. This could presumably occur if the gradient is evaluated at the faces of the cells whilst the pressure is defined at the centre.

In summary I would like to know where the gradients are evaluated in OF.

Thanks in advance,

Shaun