CFD Online Discussion Forums

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (https://www.cfd-online.com/Forums/openfoam-solving/)
-   -   BoussinesqApproximation for incompressible flow (https://www.cfd-online.com/Forums/openfoam-solving/58272-boussinesqapproximation-incompressible-flow.html)

imano August 19, 2008 07:45

Hi Fabian, Thank you for at
 
Hi Fabian,

Thank you for attaching your code again.

As a matter of fact I have made fixed heat flux B.C. library like you have made,
but I intentionally remove heat flux B.C from the airConditionedRoom tutorial case
in order to decrease installation process like compiling addtional custom library.

However the fixed flux B.C. is more general and elegant in this tutorial indeed,
so I wrote a Wiki page of my fixed heat flux B.C. library and added an
option to use heat flux B.C. into airConditionedRoom tutorial case.

http://openfoamwiki.net/index.php/Contrib_wallHeatFlux
http://openfoamwiki.net/index.php/Ma...onditionedRoom

Please have a look at Wiki pages and source code for detail.

The Last question about the wall function:
The separate treatment for temperature might be needed indeed,
but currently I have no plan to implement them soon...
So I wish someone get started on them... http://www.cfd-online.com/OpenFOAM_D...part/happy.gif

Masashi

braennstroem August 19, 2008 13:24

Nice :-) Do you have a hint, a
 
Nice :-) Do you have a hint, about implementing it?

braennstroem August 19, 2008 13:24

... I mean the wall treatment.
 
... I mean the wall treatment.

christian November 4, 2008 06:12

In the code by Masashi, the wa
 
In the code by Masashi, the wall heat transfer is calculated as:
temperature gradient = q/(alpha_eff*Cp0*rho0)

Cp will not vary much with temperature, but density will change more than negligable for my case. What do you think, wouldn't it be better to express rho in terms of rho0, beta, g, T and T0 (Boussinesq approximation)?

Hope to have someones opinion.

Regards,
Christian Lindbäck

emilianyassenov November 17, 2008 03:56

Hi to all What is beta here
 
Hi to all

What is beta here?

can anyone tell me?

Emo

jeong November 17, 2008 04:35

Beta is the thermal expansion
 
Beta is the thermal expansion coefficient.

http://web.njit.edu/topics/Prog_Lang_Docs/html/FLUENT/fluent/fluent5/ug/html/nod e296.htm

emilianyassenov November 17, 2008 05:11

Hi Jeong Thanks for the qui
 
Hi Jeong

Thanks for the quick answer...
but i could not open your site...is it without dimension or?

thanks in advance!!

jeong November 17, 2008 07:26

Dear Emilian, The dimensio
 
Dear Emilian,

The dimension is [1/K].

You can check its dimension and value in the "/constant/transportProperties" file of the example directory.

http://www.engineeringtoolbox.com/ai...ies-d_156.html
http://en.wikipedia.org/wiki/Coeffic...rmal_expansion

Jeong

scurtu November 28, 2008 03:59

Dear Hrvoje, is the Boussin
 
Dear Hrvoje,

is the Boussinesq approximation solver
/OpenFOAM-1.4.1-dev/applications/solvers/heatTransfer/boussinesqBuoyantFoam/
compatible with OpenFOAM-1.5?
If not what modifications it request?

Nicoleta

hjasak November 28, 2008 05:38

I think it will work with no c
 
I think it will work with no changes - try to compile and see what happens.

There sound le no problems.

Enjoy.

Hrv

bintoro May 13, 2009 05:20

boussinesq approximation
 
Hi,
I am new to OpenFoam. I'd like to solve the problem of natural convection heat transfer in rod bundle that generating 200 kW of power. Is the boussinesq approximation solver enough for this case, since there will be two phase flow when boiling happen?

bintoro

prabhu July 15, 2009 03:54

hello Masashi,

I am trying to solve solidification problem and have written a code. Im using the wallHeatFlux BC for cooling the walls of the mould provided by you on the wiki page.

When the liquid starts to solidify, i see that the temperature at the walls become lower and goes negative. could u give any suggestions about how to overcome this problem.


All times are GMT -4. The time now is 12:36.