[Fluidiculous]

Hi all,

I took a quick peek through the search function and didn't see a similar question so I apologize if it's been asked before.
I am doing a very simple 2D simulation of uniform flow over a bluff body. It is essentially a rectangular domain with constant flow coming in from the left and leaving on the right side. In the middle of the rectangular domain I have my bluff body. For this simulation I have activated the lift and drag coefficient monitors on the walls of the bluff body, which I have in a txt file. I was wondering how exactly Fluent calculates these coefficients?

Is there a way to monitor the shear forces and lift forces on the walls of the bluff body as I run this simulation? I assume I would need a UDF to extract these values at every time step and see if they agree with the coefficients Fluent provides, but I am not that familiar with UDFs. I have made UDFs to implement specific velocity profiles onto inlets, which I can just throw in a UDF into the boundary condition, but there isn't an option for UDFs in "wall" boundary conditions, so I am confused as to how I can monitor the variables involved in the coefficient calculations. I assume you can find the pressure on the surfaces and then integrate over the area to find the normal forces, but when I go into the surface monitor box, I'm confused as to what "Report Type" to select.

Thank you very much!

Edit #1: I should make my question clearer. When calculating the drag coefficient does fluent use only the variable values provided in the "Reference Values" tab or does it calculate the values from the solution itself?