[CNT9]

Hello,
I'm still learning about OpenFoam, and I need some helps.
I want to model a converging flow, so there are two inlets coming in and
a single outlet.
However, instead of assigning velocity differences at inlets and outlets,
I want to make this a pressure-driven flow (thus assigning only pressure values and possibly assigning velocity values as zeroGradients) - and two inlets should have different initial pressure values.
So any suggestions for good boundary conditions for two inlets and an outlet?

Thank you in advance.

[chegdan]

Originally Posted by CNT9

Hello,
I'm still learning about OpenFoam, and I need some helps.
I want to model a converging flow, so there are two inlets coming in and
a single outlet.
However, instead of assigning velocity differences at inlets and outlets,
I want to make this a pressure-driven flow (thus assigning only pressure values and possibly assigning velocity values as zeroGradients) - and two inlets should have different initial pressure values.
So any suggestions for good boundary conditions for two inlets and an outlet?

Thank you in advance.

Try looking at

http://www.cfd-online.com/Forums/ope...-inlet-bc.html

and

http://www.cfd-online.com/Forums/ope...-openfoam.html

and then search the forum a little more for "pressure inlet"

I do remember that specifying pressure at the inlet, it is very easy to create hypersonic flow (not sure where I read that)...so be careful. Also, remember that if you use solvers like simpleFoam, the value you are specifying is actually pressure divided by fluid density.

Cheers,

[sundark28]

Hi guys,

I´m pretty new in OpenFoam (i m using Openfoam2.1). I consider the geometry of a cylinder and i would like to simulate a swirling turbulent flow (LES Simulation). I want to change the entry condition for the velocity field with the following expression: (i want a tangetial velocity profil which depends on radius)

" variables: Ur (radial velaocity), Ut (tangential velocity), r_vc (radius of the vortex), v_max (maximal velocity)

expression:
for 0 < radius < r_vc Ur = V_max * radius / r_vc

for r_vc < radius < R (radius of the cylinder) Ur = V_max *r_vc / radius"

Thanks in advance for your help !!

[chegdan]

Originally Posted by sundark28

Hi guys,

I´m pretty new in OpenFoam (i m using Openfoam2.1). I consider the geometry of a cylinder and i would like to simulate a swirling turbulent flow (LES Simulation). I want to change the entry condition for the velocity field with the following expression: (i want a tangetial velocity profil which depends on radius)

" variables: Ur (radial velaocity), Ut (tangential velocity), r_vc (radius of the vortex), v_max (maximal velocity)

expression:
for 0 < radius < r_vc Ur = V_max * radius / r_vc

for r_vc < radius < R (radius of the cylinder) Ur = V_max *r_vc / radius"

Thanks in advance for your help !!

This is usually my go to answer on these, but why not try groovyBC (http://openfoamwiki.net/index.php/Contrib_groovyBC) or go ahead and install swak4foam (http://openfoamwiki.net/index.php/Contrib/swak4Foam) to get even more tools, and look at

http://www.cfd-online.com/Forums/ope...locity-bc.html

that will cover it for you. As always, use your search skills on the forum. Good luck.