[Taaresh]

Hello all!

I have been trying to define a momentum source (body force) term by extracting a cell zone in FLUENT. The objective is to check the downstream velocity profile because of this source term in the y direction (which is perpendicular the the direction of flow). Now, I extracted a cell zone with volume V and used a force F to get the body force, say Fb. On doubling the force F, the velocity changes are significant however if I keep the same force and extract only half the volume and accordingly give the body force term, there is hardly any change in downstream velocity.

In both the cases, I have doubled the body force as compared to the base case. First by doubling the force and second by halving the volume. So ideally the results should be the same, right? However I am getting a difference of about 80% in downstream mass weighted average velocity.

Can someone please help me with this?

Thanks in advance