I have modify a little bit cylinder2d.
I put a velocity inlet 3ms^-1 and a pressure outlet 0
I have used air_dynamic_viscosity 1.9e-5 try to have Re#400-100
(trying with deltaP inlet100Pa outlet0Pa with no succes seem not works…)
I compare with a real system wich is an air flow on a little valve moving :
I have a dynamic pressure in front of th valve simulated wich is instantanly moving but in reallity this is smoth change
time_constant = 0,0386054 so rising time is around 0.15s (due to lag time…) not an instannaly response.
Maybe I do an error.
What could be the problem in this kind of simulation?.
I have doing like this.
It is not an instability!
My simulation didn’t realise the time changement of state : when we open the valve we obtain a step changement of pressure. This is not realistic value. When opening the valve pressure seem change immediatly…
We measure it on a real system : the time changement is about 0.15s this is not immediatly change.
I use BGK to calculate but maybe I do use MRT to avoid this phenomen ?