BoussinesqApproximation for incompressible flow

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

 July 12, 2005, 10:30 You must either move the g #1 Senior Member   Join Date: Mar 2009 Posts: 854 Rep Power: 13 You must either move the g*alpha*(T-TRef) term into the UEqn construction statement fvVectorMatrix UEqn ... or also include the term in the flux prediction by including it in U = UEqn.H()/A; and remove it from the momentum correction statement U -= fvc::grad(p)/A + (g*alpha*(T-TRef))/A;

 June 9, 2006, 16:21 Christian, have you had any lu #2 ccless Guest   Posts: n/a Christian, have you had any luck? I have been thinking about a boussinesq solver, but haven't had enough time to write it. Does yours work and if so, what tricks did you use to get it up and running. Thanks

 August 2, 2006, 09:36 Hi, we also want to build a #3 mkk Guest   Posts: n/a Hi, we also want to build a boussinesq-approximation. You wrote your solver in the version 1.2. Am I right? We changed your idea, so it could work in 1.3. But we had a problem with the line: g*alpha*(T-TRef) what type is TRef and T and where you definded it? Thanks Martin

 February 16, 2007, 12:34 Hi, also trying to get an i #4 Senior Member   Thomas Jung Join Date: Mar 2009 Posts: 100 Rep Power: 8 Hi, also trying to get an incompressible boussinesq-approx. solver running ... I got something working, basically what Christian has posted, with the corrections by Henry. Works mostly, but sometimes I get problems at boundaries (using a zeroGradient B.C. for pressure) I thought I needed a pressure boundary condition, and implemented one similar to the existing wallBuoyantPressure - just computing the pressure gradient as g*beta*(T-TRef) Also at first glance seemed to work, gives a smooth looking pressure field, but then I realized strange vectors and pressures at the pressure reference cell, finally calculations diverge. Fixing pressure at some boundary, instead of using pEqn.setReference(pRefCell, pRefValue), works. Not setting a pressure reference the pressure solver (AMG or ICCG) diverges. almost forgot - using OpenFOAM 1.3 Any hint would be greatly appreciated... Thank you ! Thomas

 March 17, 2007, 15:23 For the lazy ones out there, I #5 Senior Member   Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,758 Rep Power: 21 For the lazy ones out there, I have written a Boussinesq approximation incompressible buoyant flow solver with constant material properties. You can get it from the link below, including a tutorial case: boussinesqBuoyantFoam Currently, it is laminar and quite easy to understand, it will swallow the wall bouyant pressure b.c. and I think it's a pretty decent example. Extensions to turbulent, real material properties etc are straightforward but uninteresting (for me!). Enjoy, Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

 March 17, 2007, 18:19 This link is dead. #6 Member   rafal zietara Join Date: Mar 2009 Location: Manchester, UK Posts: 60 Rep Power: 8 This link is dead.

 March 17, 2007, 19:26 Stupid, sorry: boussinesqBuoya #7 Senior Member   Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,758 Rep Power: 21 Stupid, sorry: boussinesqBuoyantFoam Apologies, Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

 May 16, 2007, 09:19 Hrvoje, From one of the laz #8 Senior Member   Thomas Jung Join Date: Mar 2009 Posts: 100 Rep Power: 8 Hrvoje, From one of the lazy ones: Your implementation suffers the same problems (mass conservation fluxes at walls not parallel to gravity and not at reference temperature). You can see it if you make your cavity hot at bottom, cold on top, and adiabatic sidewalls. A pressure B.C. computing pressure gradient as g*beta*(T-TRef), but without contribution to mass fluxes, works. There is also no need to have an extra density field - which for me is the main point of the Boussinesq approximation. regards, Thomas

 March 7, 2008, 09:01 Hrvoje, we tried to get your #9 New Member   sonia esteban Join Date: Mar 2009 Posts: 12 Rep Power: 8 Hrvoje, we tried to get your Boussinesq approximation incompressible buoyant flow solver, but we get the following message The page cannot be found We wait your help... Sonia

 March 7, 2008, 13:36 Sorry, probably got deleted: t #10 Senior Member   Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,758 Rep Power: 21 Sorry, probably got deleted: try it from SVN: http://openfoam-extend.svn.sourceforge.net/viewvc/openfoam-extend/trunk/Core/Ope nFOAM-1.4.1-dev/applications/solvers/heatTransfer/boussinesqBuoyantFoam/ Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

 March 10, 2008, 06:47 Hi,Hrvoje Thank you for your #11 New Member   sonia esteban Join Date: Mar 2009 Posts: 12 Rep Power: 8 Hi,Hrvoje Thank you for your help, We can download your files. We start working on this case. Sonia

 August 13, 2008, 09:41 Hi, somebody created a bous #12 Senior Member   Tian Join Date: Mar 2009 Location: Berlin, germany Posts: 102 Rep Power: 8 Hi, somebody created a boussinesq approximation solver with turbulent already and can share it with me? Thanks a lot. Bye __________________ BIM HVACTool, The Green Building Simulation Tool for OpenFOAM, Energy Plus and Radiance.

 August 14, 2008, 16:53 Yes: have a look at: http:/ #13 Senior Member   Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,758 Rep Power: 21 __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

 August 15, 2008, 03:23 Hi Hrvoje, this solver is f #14 Senior Member   Tian Join Date: Mar 2009 Location: Berlin, germany Posts: 102 Rep Power: 8 Hi Hrvoje, this solver is for buoyancy-driven laminar flow. I like to try the boussinesq approximation with turbulent flow. thanks __________________ BIM HVACTool, The Green Building Simulation Tool for OpenFOAM, Energy Plus and Radiance.

 August 15, 2008, 05:14 Hi Thomas, I just wrote Wik #15 Member   Masashi IMANO Join Date: Mar 2009 Location: Tokyo, Japan Posts: 34 Rep Power: 8 Hi Thomas, I just wrote Wiki page of Boussinesq-Approximation solver for turbulent flow. http://openfoamwiki.net/index.php/Co...yantSimpleFoam Also I wrote Wiki page of tutorial case using this solver. http://openfoamwiki.net/index.php/Ma...onditionedRoom Bye! Masashi

 August 15, 2008, 05:46 Hi Masashi, thanks a lot! A #16 Senior Member   Tian Join Date: Mar 2009 Location: Berlin, germany Posts: 102 Rep Power: 8 Hi Masashi, thanks a lot! Arigato Bye __________________ BIM HVACTool, The Green Building Simulation Tool for OpenFOAM, Energy Plus and Radiance.

 August 15, 2008, 08:02 Hi Masashi, nice work! I like #17 Senior Member   Fabian Braennstroem Join Date: Mar 2009 Posts: 407 Rep Power: 10 Hi Masashi, nice work! I like your tutorial with the makefile and the python meshing :-) Fabian

 August 18, 2008, 10:04 Hi Masashi, I have a quest #18 Senior Member   Fabian Braennstroem Join Date: Mar 2009 Posts: 407 Rep Power: 10 Hi Masashi, I have a question about your implementation of the temperature equation. As I get it, you add a defined heat flux to the equation, which is activated by the internal field of Q!? I tried a more general approach by defining a heat flux b.c. using: const boussinesq::RASModel& RAS = db().lookupObject("RASProper ties"); scalarField nuEffWall = RAS.nuEff()().boundaryField()[patch().patch().index()]; scalarField alphaEffWall = nuEffWall /Prt; gradient()=(heatFlux_/(Cp0*rho0*alphaEffWall)); Based on your added b.c. one could use: wall { type fixedHeatFlux; heatFlux 5.0; gradient uniform 200; } Though I am not sure yet, how to validate this b.c. with a really simple setup!? And right now, it is a static Prt, Cp0 and rho implementation. Does anyone know, how to get those value by a dictionary? I got one more question about the wall function. Is it correct, that as long as one uses a constant Pr model is used, the wall effects are all included in the turbulence model and no separate treatment for the temperature near-wall behavior is needed? Fabian

 August 18, 2008, 11:42 Hi Fabian, It seems that f #19 Member   Masashi IMANO Join Date: Mar 2009 Location: Tokyo, Japan Posts: 34 Rep Power: 8 Hi Fabian, It seems that fixedHeatFluxFvPatchScalarField.[C,H] are not attached properly in your previous post. So please attach them again! Masashi

 August 18, 2008, 13:21 oh http://www.cfd-online.c #20 Senior Member   Fabian Braennstroem Join Date: Mar 2009 Posts: 407 Rep Power: 10

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post mkk OpenFOAM Running, Solving & CFD 0 August 2, 2006 09:32 Hun Jung Main CFD Forum 4 August 11, 2003 10:10 Shahriar Main CFD Forum 7 March 7, 2003 09:53 A.M.Yang Main CFD Forum 1 July 3, 2002 07:58 zhwm FLUENT 5 February 7, 2002 22:44

All times are GMT -4. The time now is 16:21.