[Himanshu_Shrivastava]

Hello All,
I am new to openFoam and currently confused about p_rgh setting.
I have read the theory about p_rgh and have read some post about this but I didn't got what I am looking for.

from the post linked below:
Correct boundary conditions for p_rgh (special for vertical patches)

I came to know about the formula p_rgh=p-g(h_hRef) and the value of hRef is set 0 by default.
My doubt is the will default 0 value will work for every simulation?
Suppose i modeled my geometry from xy-plane (i.e. z=0) and I modeled another geometry from z=-3 plane. If i keep all the BC same and even the default h_ref value (i.e. 0) is kept same, will my answer will be same.

if not, how should I change my h_ref value? and how should we decide this value?

[geth03]

as soon as you have the same reference height for all, which you automatically have, and also the same gravitational acceleration,
your gradient should be the same, independant of the exact value.