hi all

I have run program anb.f in many lx and ly

but pressure is not correct while u and v seems to be correct

I have this question:

whether press have meaning or not in p=rho*cs^2 ?

when we use incompressible we must became rho=constant

with compressibility error of LBM in density, how I can find pressure gradient in domain?

I understand lbunits and those conversion to physical units but pressure with conversion and without conversion is incorrect

thanks

maybe you can find something help in the paper:On pressure and velocity boundary conditions for the lattice Boltzmann BGK model(Zou/He).

good luck@@

dear aass277

hi

thanks for your reply

I was read that paper previous time and I review that again now

but I have my problem again now

is it possible to you to help me

have a nice time

mehdi

dear Jonas Latt

thanks for your kind reply

I try to prepare a 3D code in LB but in this time I want to compare my 2D code answers with others answers.

I try to run 2d cavity flow and channel flow.

amplitude of pressure is incorrect and also that have very oscillation in domain.

I am not sure to reach steady state , how I can sure to reach steady state? I run program 200000 iteration.

I see mean velocity in one cross section and if that value not changed for long time I stop the program.

in p=rho*cs^2 I find very small pressure change in real unit because rho*cs^2 is about=1/3 in lb units.

what is this p? is it a difference or ratio of pressure?

my problem is flow between two stationary wall

lx=402 ly=82

widthreal=0.1m

rho=997.1 kg/m^3

dxreal=0.1/80

dtreal=dxreal**2*nulb/nureal

nureal=0.897d-6

rholb=1

re=10

mach=1/(ly-2)=1/80

dx=1

dt=1

thanks

have a nice time

mehdi