SimScale CAE Forum

How does "Momentum Source" work?

I am trying to figure out what “momentum source” actually does.
I have read these two pages:

but none of them provide any formulae that would help figure out how the input “mean velocity” is represented in the Navier Stokes equations.

Let’s say I assign a “momentum source” to a box and provide a desired mean velocity.
I assume that the “momentum source” feature then computes a mass-specific force F required to achieve that the velocity averaged in the box equals the user-input mean velocity.
I assume that this mass-specific force is imposed at every location inside this box, F thus being constant in space within the box.

What I actually need is a means of assigning a mass- or volume-specific force that is than added to the right-hand side of the Navier-Stokes equations.
This does not seem to be implemented though.

Is this correct?

Hi @bastian!

I can check that and see if there is just a simple change in the velocity terms. More information will follow!