code_saturne User's Forum

hello,
How to set the pressure inlet boundary conditions in version 4.0?
The case is an incompressible fluid. I want to fix total pressure of the inlet and static pressure of the outlet.
thanks!

I set the outlet as "isolib" and the inlet like this in “cs_user_boundary_conditions.f90” . But it was divergence.
itypfb(ifac)=iindef

icodcl(ifac,ipr) = 1
rcodcl(ifac,ipr,1) = 1.e5

icodcl(ifac,iu) = 3
rcodcl(ifac,iu,3) = 0

icodcl(ifac,iv) = 3
rcodcl(ifac,iv,3) = 0

icodcl(ifac,iw) = 3
rcodcl(ifac,iw,3) = 0

Hello,

I am not sure how this combination would work, relative to the outlet pressure.

If you impose both inlet and outlet pressures, you have more chances of running correctly, but thi is often more tricky to set up than imposing an inlet velocity.

Best regards,

Yvan

Hello yhuang,

In version 6.0.5,
for pressure inlet boundary condition, I can ues this,
_________________________________
call getfbr('inlet', nlelt, lstelt)
do ilelt = 1, nlelt
ifac = lstelt(ilelt)
itypfb(ifac) = ientre

!Dirichlet B.C for pressure:
icodcl(ifac,ipr) = 1
rcodcl(ifac,ipr,1) = 101325.633

!Neumann B.C for velocity:
icodcl(ifac,iu)= 3
icodcl(ifac,iv)= 3
icodcl(ifac,iw)= 3
enddo
_________________________________

But you should keep in mind that
calculation often become divergent if you use tetra mesh.

Best regards,
Tsubasa

Hello,

computations are often less stable on lower quality/less regular meshes, but that does not mean they automatically diverge...

Best regards,

Yvan