RMS Values in CFD Post
 

Hello to everyone,

I am trying to calculate the RMS value of the velocity and density in a internal 2D steady simulation of the injection of a thruster. The point is that I am trying to create an expression to calculate the RMS values as long as I could not find this value in the function calculator tool. For the velocity, for instance, I would like to calculate:

URMS = sqrt(1/A * int(V(r)^2-Vavg^2) dr )

I do not know how can I represent this function in a expression with the CFX language in order to get this RMS value in a reference plane. I have tried this expression but it is not working:

URMS = sqrt(1/area(@Plane 1) * sum(Velocity^2-ave(Velocity)@Plane 1))

I am not sure how to discretize the expression as long as the values extracted are the velocity or density in each node. Sorry If it not so clear but I am a begginer in CFX language.

Thank you!