[ara]

Hi All,
I have been working on a curved surface Jet Array Heat Impingement case in Star CCM. Reynolds number based on first row jet is 125000. My first goal is to have correct in plane velocity profiles in jet row sections. I tried many cases, with and without heat transfer, steady and unsteady(with steady solution as initial) and my iteration went over 34000. But it seems that the solution has not been converged since the shape of velocity profile changes. I checked the profile and the shape of flow between jet and target plate changes dramatically. I use structured mesh with Y+<=1 in jet and target plate and unstructured mesh elsewhere. My turbulence model is v2f. Also, I fixed "pipe out" as target mass flow rate and set a mass flow rate.
Any suggestion would be highly appreciated.

[ara]

Hi,
I really appreciate if anyone could give me a feedback on the below case.
I reached 46000 iterations, v2f, with heat transfer but still no trace of convergence.

Originally Posted by ara

Hi All,
I have been working on a curved surface Jet Array Heat Impingement case in Star CCM. Reynolds number based on first row jet is 125000. My first goal is to have correct in plane velocity profiles in jet row sections. I tried many cases, with and without heat transfer, steady and unsteady(with steady solution as initial) and my iteration went over 34000. But it seems that the solution has not been converged since the shape of velocity profile changes. I checked the profile and the shape of flow between jet and target plate changes dramatically. I use structured mesh with Y+<=1 in jet and target plate and unstructured mesh elsewhere. My turbulence model is v2f. Also, I fixed "pipe out" as target mass flow rate and set a mass flow rate.
Any suggestion would be highly appreciated.

[ping]

is it possible that the model is telling you that the flow is in fact actually unsteady and that you might never get a converged solution in the normal sense and so need to do field monitors to obtain a mean solution of many timesteps

[er_trebbia]

Hi Ara

I've some problems in convergence with v2f model and want to share with you something I learned about.
My case is a slot jet of air impinging a cylinder, in 2D (for now).
I changed my B.C. several times, and more stable configuration I found is shown in this post, at the end of page, here.
Running the same mesh with two Reynolds number, I obtained a convergence just with the higher one, with a 1st/2nd order blended closure.
When the simulation diverges, I can say that the main problem is f, at the wall but also in the high gradient region in mixing layer between the jet and stagnant air.

[sabrina]

Originally Posted by ara

Hi,
I really appreciate if anyone could give me a feedback on the below case.
I reached 46000 iterations, v2f, with heat transfer but still no trace of convergence.

Please, you can tell how you do the "heat transfert", my problem is the flow around a plate, I find a good result without heat transfert and now must redo the study but with "heat transfer" and I dont know how I add this