CFD Online Discussion Forums

CFD Online Discussion Forums (
-   OpenFOAM Pre-Processing (
-   -   interfoam bc (

amin66 July 22, 2012 01:47

interfoam bc
Hi Foamers

i have problems with pressure boundary condition in interfoam yet. (openfoam 1.6)

1. what is P in interfoam? static or total or gage pressure?
2. what's the buoyantpressure condition?
3. does interfoam solve equations completely dimensionless?


santiagomarquezd July 26, 2012 16:52

Hi Amin,

1. In 1.6 is static pressure.
2. Is a condition intended for walls where no pressure is known, the pressure gradient is set to the value of rho*g & wall_normal
3. No, the full dimensional equations are solved.


amin66 July 28, 2012 15:51

Hi Santiago
Thanks for your reply.

"" 3. No, the full dimensional equations are solved. ""
you mean that we have to use exact properties for fluid and use meter in our simulation.

santiagomarquezd July 28, 2012 18:07

Hi, it means that the Eqns. are written the same you find in a book doing the mass and momentum balances without obtaining the dimensionless version. So that the velocities are in m/sec, pressure in Pa and viscosity in Pa sec (dynamic viscosity).


amin66 July 29, 2012 13:41

Thanks for your attention
my means was that if in simulation we want the Re=(u*d)/nu=180 , Can we set velocity(u), diameter(d) or nu in arbitary values to obtain Re=180 ?

means: is simulation with u=180 m/s , d=1 m , nu=1 same with simulation with u=180*10^-6 , d=1 , nu=10^-6 ????

santiagomarquezd July 30, 2012 14:54

Amin, take into account that in multiphase flow you have other non-dimensional numbers, like Froude, Eotvos, Weber, etc. so that, in order to have similarity you have to check all the non-dimensional relevant numbers of you problem.


amin66 August 1, 2012 06:15

yes Santiago. of course i do that.
thank you

All times are GMT -4. The time now is 12:51.