Fourth Order Runge Kutta time integration

syavash · May 22, 2019, 05:16

Quote:

Originally Posted by Hen Cruise

Hi, syavash, thanks very much for your great work, and i want to know,

Is it possible to modified the 'RK4' be an convenient 'option' in fvschemes file for ddtSchemes such as 'Euler' or 'backward'? then used for most compressible or incompressible solvers?

Well, I think it would be a great idea! However, it cannot be employed as a temporal scheme in the current form. Probably some if-clause will be necessary to differentiate between incompressible and compressible conditions.

Kind Regards,
syavash

kermelosh · July 1, 2019, 20:10

Hey Syavash,

It is clear from the code that solver running time highly depends on the number of times the pressure correction step is implemented. Do you think that there is a way to reduce the number of the pressure correction step while maintaining the 4th-order RK projection for the velocity field? For example, if one only evokes the pressure correction at the end only once or twice between intermediate time steps.

Thanks

syavash · July 2, 2019, 10:19

Quote:

Originally Posted by kermelosh

Hey Syavash,

It is clear from the code that solver running time highly depends on the number of times the pressure correction step is implemented. Do you think that there is a way to reduce the number of the pressure correction step while maintaining the 4th-order RK projection for the velocity field? For example, if one only evokes the pressure correction at the end only once or twice between intermediate time steps.

Thanks

Hi,

I can only think of the 3rd-order Runge-Kutta as a reply, which is of-course 3rd-order accurate in time but demands fewer number of pressure correction steps. I have already implemented that and it was faster, but don't remember it gave a huge difference over 4th-order Runge-Kutta.

Best Regards,
Syavash

syavash · July 2, 2019, 10:37

Well, I have uploaded both solver and its test case on my Github repository. On my reposityory, one can also find a bunch of useful codes WRT incompressible LES in OpenFoam.

https://github.com/syavash20/TurbLab

Best Regards,
Syavash

kermelosh · December 20, 2019, 20:13

Hey Syavash,

In your opinion, can the RK4Foam solver be used for an FSI study? I would like to explore its application for FSI studies with LES turbulent modeling.

Nico994396 · November 10, 2022, 03:36

Hi Ville,
i tried to implement a fully explicit RK4 scheme for compressible flows (Euler Equations) , following your paper, but it seems that not work ( some waves are created near the boundaries )

Can you give me some explanation about that, thank you.

July 2, 2019, 10:37		#44
syavash Senior Member Ehsan Asgari Join Date: Apr 2010 Posts: 473 Rep Power: 18	Well, I have uploaded both solver and its test case on my Github repository. On my reposityory, one can also find a bunch of useful codes WRT incompressible LES in OpenFoam. https://github.com/syavash20/TurbLab Best Regards, Syavash aerospaceman and Lucifinil like this.

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July 1, 2019, 20:10		#42
kermelosh New Member agSilverMAN Join Date: Aug 2018 Posts: 6 Rep Power: 8	Hey Syavash, It is clear from the code that solver running time highly depends on the number of times the pressure correction step is implemented. Do you think that there is a way to reduce the number of the pressure correction step while maintaining the 4th-order RK projection for the velocity field? For example, if one only evokes the pressure correction at the end only once or twice between intermediate time steps. Thanks

December 20, 2019, 20:13		#45
kermelosh New Member agSilverMAN Join Date: Aug 2018 Posts: 6 Rep Power: 8	Hey Syavash, In your opinion, can the RK4Foam solver be used for an FSI study? I would like to explore its application for FSI studies with LES turbulent modeling.

November 10, 2022, 03:36		#46
Nico994396 New Member Nico Join Date: Feb 2018 Location: Turin Posts: 8 Rep Power: 8	Hi Ville, i tried to implement a fully explicit RK4 scheme for compressible flows (Euler Equations) , following your paper, but it seems that not work ( some waves are created near the boundaries ) Can you give me some explanation about that, thank you.