[balrog_f]

Hi,

I am trying to investigate the effect of dimples to the flow. Therefore I want to do a LES where a specified airflow flows through an infinte channel of a dimpled and a non-dimpled wall (Re ~ 12000). Therefore I am using periodic boundary conditions in streamwise direction. What would be the approach for this, using the pressure change or the mass flow rate option as interface model?
My guess would be the mass flow rate cause I have everything I need for this (velocity, geometry). But I am not sure what I should use as pressure update multiplier? Or should I use pressure change?

[ghorrocks]

If you specify the pressure change then you get whatever flow rate that results in. If you specify the mass flow rate you get whatever pressure drop that results in.

So you use the option which matches the information you know about the flow. So if you want to run at a specified Re number that means you should use the mass flow rate option.

I am not sure about the pressure update multiplier, I would have to to look that up before commenting on that.

[balrog_f]

Okay I will try the mass flow rate option. I will calculate the mass flow rate via an expression, which then I will use at the additional interface model tab for the mass flow rate. I have my desired velocity (Ubulk) and my defined interface areas (channel "inlet" and channel "outlet"). My expression would look like this :

massflow = density*Ubulk*area()@inlet

Is this the right approach?

[ghorrocks]

Sounds pretty good to me.

[balrog_f]

Thank you very much for your help Glenn. I will do it like this!