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#1 |
New Member
Onur Koç
Join Date: May 2020
Posts: 12
Rep Power: 6 ![]() |
Hi,
I am trying to validate onera m6 wing (transonic airfoil) with openFoam. By the help of Micheal Aletto case (https://wiki.openfoam.com/OneraM6_by_Michael_Alletto) I run very well for the rhoSimpleFoam solver. But I want to see results of the rhoPimpleFoam to make comparison. I can get good results for the rhoSimpleFoam, I can see the shock waves. On the other hand rhoPimpleFoam is also run but results are not good.With changing only fvSolution fvSchemes folders (from rhoPimpleFoam tutorials) for rhoPimpleFoam and using smallar deltaT I run the simulation. It is converge but results are not what I want. So as a result, to get good result with rhoPimpleFoam what I should check , what is the reason of bad results for rhoPimpleFoam ? Thanks for help. |
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#2 |
Senior Member
Herpes Free Engineer
Join Date: Sep 2019
Location: The Home Under The Ground with the Lost Boys
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some other tool that can be used? https://hisa.gitlab.io/archive.html
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The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror |
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#3 |
New Member
Onur Koç
Join Date: May 2020
Posts: 12
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I didn't understand exactly that other tools mean. But I should do this with openFoam. Because it is my graduating project topic
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#4 |
Senior Member
Herpes Free Engineer
Join Date: Sep 2019
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hisaFoam is a module based on OpenFOAM (i.e. you need OpenFOAM to utilise hisaFoam). It is highly capable for compressible external flow applications. Otherwise, with the default OpenFOAM solvers, you might find yourself banging your head against the wall when something goes wrong in your high-speed compressible flow simulations.
At least, you can find that their tutorial suite contains the ONERA case as well. (this is not an investment advice). Hope this helps.
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The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror |
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#5 |
Senior Member
Michael Alletto
Join Date: Jun 2018
Location: Bremen
Posts: 616
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Did you try local time stepping
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#6 |
New Member
Onur Koç
Join Date: May 2020
Posts: 12
Rep Power: 6 ![]() |
Thanks for your helps but I should also specied that I should make this analysis rhoPimpleFoam and rhoCentralFoam also. At the and we will compare the all results of pimple,central and simple. This is my final project.
You mean that I can not get good results by using rhopimplefoam ? Because I want to know whether I can solve this case by rhopimplefoam or not. rhoSimpleFoam can solve but why rhoPimpleFoam results are so far away the experimental results. |
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#7 |
New Member
Onur Koç
Join Date: May 2020
Posts: 12
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Yes I have used adjustible time step it is rearranging automatically.
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#8 |
Senior Member
Herpes Free Engineer
Join Date: Sep 2019
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You can get good results with rhoPimpleFoam. Having said that it might not be starightforward to get them. Apart from my personal experience, I don't have any evidence, I am afraid. Just be extra careful with rho* solvers, because they were developed for HVAC in mind, not for high-speed aero.
Hope this helps.
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The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror |
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#9 |
Senior Member
Michael Alletto
Join Date: Jun 2018
Location: Bremen
Posts: 616
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There is a tutorial where the 2d flow of a transonic airfoil is calculated with rhoPimplefoam
https://wiki.openfoam.com/NACA0012_by_Michael_Alletto Maybe you find some hints there |
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#10 |
Senior Member
Michael Alletto
Join Date: Jun 2018
Location: Bremen
Posts: 616
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There is another tutorial which simulates the supersonic flow around a sphere with rhoPimplefoam. The bow shock and expansion waves are captured desently. A suggestion how to implement a sensor to capture the high gradients around the shock is also included. https://wiki.openfoam.com/AMR_supers...ichael_Alletto
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#11 |
New Member
Onur Koç
Join Date: May 2020
Posts: 12
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thank you so much for your helps and interest. I will look and try.
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#12 |
Senior Member
Herpes Free Engineer
Join Date: Sep 2019
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Could you please consider to share your results and the test cases herein to help others after you will accomplish your studies? I'm curious how these rho* solvers would act on this sort of engineering problems. Thanks.
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The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror |
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#13 |
New Member
Onur Koç
Join Date: May 2020
Posts: 12
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Of course. If I can reach the experimental results, I will share all things
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#14 | |
New Member
Onur Koç
Join Date: May 2020
Posts: 12
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Quote:
I couldn't exactly get the correct results but I have proceed a little. In my fvSchemes , I have written div(phid,p) $Gauss limitedLinear 1 instead of $turbulance. ( I don't know how they works or effect the results theoritically but I have write it from examples tutorials.) Then my results are more closer to experimental results in 14. second . At this point I have said it is okey it will done. ![]() |
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#15 |
Senior Member
Herpes Free Engineer
Join Date: Sep 2019
Location: The Home Under The Ground with the Lost Boys
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Could you quantify what you mean by 'nonsense'?
Log files with the minMax function object for p, T and U could be helpful. In the worst case scenario, the Batman can be summoned. The bat signal is the limitTemperature and limitVelocity fvOptions. Hope this helps.
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The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror |
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#16 |
Senior Member
Michael Alletto
Join Date: Jun 2018
Location: Bremen
Posts: 616
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Hello. I tried to simulate the onera M6 wing case with the same setting using rhoPimpleFoam as with the tutorial where I used rhoSimpleFoam. I used a local time stepping to accelerate the convergence to steady state. However after 4000 iteration steps no converged solution could be reached (I monitored the lift force which was not converged).
I found this result interesting since in principle if we underrelax rhoSimpleFoam a very similar system of equation is solved as with local time stepping and rhoPimpleFoam. Find attached the system folder I used. I think it is enough to replace this system folder with the one of the tutorial to reproduce the results |
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#17 |
Senior Member
Michael Alletto
Join Date: Jun 2018
Location: Bremen
Posts: 616
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What I can further suggest is to increase along wing resolution in the vicinity of the shock in order to capture the sharp gradients better
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#18 |
Member
Join Date: Dec 2018
Posts: 75
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These are the problems i face everyday unfortunately ...
Please share your fvSchemes and fvSolution files. Then i can advice you some schemes for try. 0.orig of tutorial was well treated, i checked it. If you made some changes, let us know. As advices: 1-Initialize with potentialFoam or just use the result of converged case with rhoSimpleFoam 2- Divergence schemes should be run to start with first orders then pass to second order(not necessarily). 3-Do not limit Pressure gradient 4- Treat div(phi,U) as directional like Gauss linearUpwindV grad(U) 5- If nonorthoganility is higher, you might treat advance in interpolation of U. Last edited by hbulus; May 28, 2021 at 01:50. |
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#19 |
Senior Member
Herpes Free Engineer
Join Date: Sep 2019
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"Openfoam is just like women, treat as naive;"
@Onur Koç, and treat this answer as a sexist bullshit.
__________________
The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror |
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Tags |
rhopimplefoam, rhosimplefoam |
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