[rajcfd]

Hi everyone,


I have been trying simulate laminar flow with a constant heat flux through a cylindrical pipe. I have tried using buoyantBoussinesqSimpleFoam, buoyantBoussinesqPimpleFoam and even icoFoam with chnages in code. The buoyantSimple case is not converging and the other two cases are also not giving correct answers.

I have used bc T- fixedGradient along wall to incorporate heat flux thing....

Can anyone suggest why the results are not coming correct??
Please, I am stuck with this one for two weeks....I need help..

Thanks in advance....

[nimasam]

what is your fluid?
why dont you use bouyantSimpleFoam?

[rajcfd]

Hi nimasam,

My fluid is water, incompressible case. Also, I need to take into account gravity also. The solver which you are suggesting works for compressible fluids?

[nimasam]

yes, it almost use for compressible fluid, but it can be used for incompressible fluid too , if you choose apropriate thermoPhydicalDict

However you choose some how suitable solvers, would you please, share your results in different solvers, and make much more declare why results are not correct

[rajcfd]

Originally Posted by nimasam

yes, it almost use for compressible fluid, but it can be used for incompressible fluid too , if you choose apropriate thermoPhydicalDict

However you choose some how suitable solvers, would you please, share your results in different solvers, and make much more declare why results are not correct

I worked with buoyantBoussinesqSimpleFoam solver. I made the beta value zero and used potential foam initially as boundary condition was outflow.
It has worked and I have got similar profiles but the magnitude is not correct.

Like the maximum average velocity should have been 0.002 but it is coming out to be 0.0015 & similarly the expected temperature ranges were 307-338 but it is giving 301-334.
I have checked the bc's. It looks correct to me. So, why it is so?

[nimasam]

its damn close , maybe you need to play with ur numerical schemes forexample using second order schemes or refine your mesh

[rajcfd]

Originally Posted by nimasam

its damn close , maybe you need to play with ur numerical schemes forexample using second order schemes or refine your mesh

Thanks nimasam... I m working on it.

[Umut]

Hello good foamers,

I'm a new beginner in openfoam. I need to ask 2 questions.
A)I'd like to solve a laminar channel flow in 2D. I'll use air as the working fluid and will use constant heat flux in one boundary. I tried to use buoyantBousinesqSimpleFoam but can't figure out how to arrange case files. Here is what I tried;
1) In RASProperties, I choose turbulence off and laminar as model. I deleted every variables in 0 folder except than p_rgh and copied the p,T,U files from my_icoFoam applications.
2) I used the same BCs for p_rgh as given in the iglooWithFridges tutorial by rearranging them to the geometry which I used.
3) The rest is the same with iglooWithFridges tutorial. I ran blockMesh without error.
When I type buoyantBousinesqSimpleFoam in the terminal an error occurs concerning alphat. So how can I overcome this problem?
B) Is there any standard solver to solve this problem transient?

Kind Regards.
Umut

[nimasam]

When I type buoyantBousinesqSimpleFoam in the terminal an error occurs concerning alphat. So how can I overcome this problem?

add alphat to your 0 directory and put the values of all boundaries and internal domain zero

[Umut]

Dear nimasam;

Thank you for your reply, your suggestion worked just fine. I also found that buoyantBousinesqPimpleFoam works for transient flows.
Kind regards,

Umut