CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM Running, Solving & CFD

define hydrostatic oressure condition

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   May 16, 2016, 10:21
Default define hydrostatic oressure condition
Join Date: Mar 2015
Posts: 64
Rep Power: 3
sinatahmooresi is on a distinguished road
Hi foamers!
i'm modeling two phase case consist of water and brine. and i have a tank full of water and then a jet ob brine comes in to the tank thorough the nozzle. so i should have hydrostatic pressure condition in the tank, how can i define it?
and i should tell u that i'm using twoPhaseEulerFoam as solver. and as u know it needs a refPiont . i know there is something like this in FLUENT( operating condition) and there we can introduce a point even out of the boundary with 1e05 pa pressure. but in OP it is not possible to set the point out of the boundary. i introduced a pint in top corner of the domain and i set the pressure 0:
nOuterCorrectors 3;
nCorrectors 1;
nNonOrthogonalCorrectors 0;
pRefCell 102;
pRefValue 0;

after running the model values of p and p_rgh have big values ! liek 6e04
(the height of the tank is 0.5m !)
but there is one point that is interesting between wrong values of P and P_rgh
and that is correct differences of pMean
for example with consideration 0.5 height we must have abour 5000 pa difference between bottom and top of the tank
and it is visible :
top value :6.08e04
bottom value:6.574e04
the values are wrong but the difference is about ~=5000 and correct
so what is going on ?
any help would be appreciate
sinatahmooresi is offline   Reply With Quote

Old   May 16, 2016, 13:02
Senior Member
Mahdi Hosseinali
Join Date: Apr 2009
Location: NB, Canada
Posts: 214
Rep Power: 10
anishtain4 is on a distinguished road
Pressure boundary condition:
the value you define at 0/p is the hydrostatic pressure for your case (if you are not solving compressible), so just set the pressure there.
Since you are setting a fixedValue pressure there and not zeroGradient, then it's best if you put the pRefCell on the same boundary and set the pRefValue to the same value at your boundary condition. I'm not sure but I think since you have set your p value at some boundary it is neglecting the 0 pRefValue and is calculating base on your boundaries.
anishtain4 is offline   Reply With Quote

Old   May 16, 2016, 15:27
Join Date: Mar 2015
Posts: 64
Rep Power: 3
sinatahmooresi is on a distinguished road
Hi Mahdi! thank u
I should say that my problem has compressibility! because I have tank with for walls and two symmetry plane, am I write ?( about compressibility ) and I just symmetry and wall boundary conditions
what do u mean about value of pressure in pressure condition?
internal field or boundary field ?
thank u very much
sinatahmooresi is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
define only one phasefor a interior boundary condition hamid-nice Fluent Multiphase 1 May 11, 2016 10:04
how to define a new boundary condition xck1986 OpenFOAM 0 February 23, 2011 05:56
How to define the velocity_inlet boundary condition with existed data for a face? Byron FLUENT 4 September 4, 2010 03:47
UDF FOR UNSTEADY TIME STEP mayur FLUENT 3 August 9, 2006 10:19
how to define the free surface condition major FLUENT 0 November 3, 2004 01:27

All times are GMT -4. The time now is 21:03.