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TOPIC: high velocities in stratified box model

high velocities in stratified box model 9 years 10 months ago #15481

  • 716469
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Dear Users,

I wonder if anyone come across the similar problem and can advise how to fix it. I am running the wind simulations constant in time and space in stratified "box" model. Previously, I have run similar cases on the real bathymetry case and it worked fine. With the flat bottom case the velocities at open boundary are very high. The same open boundary conditions I used on the real case and it did not cause the velocity problems. As a result of such high velocities the stratification is broken immediately. I wonder if it is a choice of mesh transformation (3) that is a problem for the box case. I have attached the surface velocities to highlight the problem area. Also I have attached the cas and fortran files just in case. The velocities are lower when I use TRISOU subroutine, but still high. Thanks in advance.

Kind Regards!

Violeta
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high velocities in stratified box model 9 years 10 months ago #15489

  • jmhervouet
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Hello,

I will not be at work for a while, but we have already done such a test case and it worked, with a stratification tilting under the influence of the wind. However I do not really see what is wrong in your test. I asked Lamia, who did the tests, to send you examples so that you can compare. The only thing that sounds strange is that you both mention an open boundary and a box model. Our test was in a closed rectangle.

With best regards,

Jean-Michel
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high velocities in stratified box model 9 years 10 months ago #15490

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Thank you Jean-Michel for your reply. Sorry, I confused you with calling it the box-model. I meant the flat bottom rectangular shape domain. Yes, you are right it has an open boundary and that where I get problems with velocity. However, you gave me a good idea! I actually have not tried wind simulation in closed domain yet, but will do it now. Thank you for asking Lamia to send me examples. I will take a look at them, sure it will help. Thank you for your help.

Kind Regards!

Violeta
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high velocities in stratified box model 9 years 10 months ago #15501

  • lamia14
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Dear Violeta,

Jean-Michel asked me to sent you an example of a stratified flow submitted to wind (In this case there is an analytical solution so you can check your results). I've attached the case file, Fortran file and a view of our results (only with closed boundaries).





File Attachment:

File Name: t3d_vent20.cas
File Size: 4 KB


File Attachment:

File Name: t3d_vent.f
File Size: 9 KB


maillage10.png


temp20.png
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high velocities in stratified box model 9 years 10 months ago #15514

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Thank you very much Lamia for your files and results. I am running stratified case with wind but with closed boundary now, so hopefully will get good results this time. I will investigate your files and see if my results are good as yours:). Thanks a mil.

Kind Regards!

Violeta
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high velocities in stratified box model 9 years 10 months ago #15515

  • lamia14
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You're welcome,

You'll find in the paper attached a derivation of an approximation of the solution.

Lamia

File Attachment:

File Name: article_emman.pdf
File Size: 993 KB
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high velocities in stratified box model 9 years 10 months ago #15516

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Thank you so much Lamia. It looks very interesting and shows the multiple layer stratification, what is exactly what I have! I will read it through. Thanks again, your help is much appreciated.

Kind Regards!

Violeta
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