[Smithstark]

Hello, I am conducting research on natural convection in a rotating enclosure, where non-inertial forces could be included in the momentum transport equation.
Prior to this, I am examining the feasibility of this method by replacing gravity with a constant momentum source. After conducting multiple simulations, it was discovered that the flow field obtained with the use of a udf was significantly dissimilar from the one obtained with default gravity in the Fluent software. It was observed that the velocity was concentrated on the initial layer of mesh in the top and bottom boundary.
The udf and the flow field differences between the udf and default gravity are provided below:

# include "udf.h"

DEFINE_SOURCE(grvY,c,t,dS,eqn)
{
real source;
source = -9.81*C_R(c,t);
dS[eqn] = 0;
return source;
}

The flow field and local zoom of high velocity zone are listed below:






While the proper flow field should look like this



Thanks for any advice！