Hello Spencer,

thank you for your response. I was just a littlw confused, because in the paper it says best practice for homogeneous directions is to use the PowerKernel and otherwise the DGKernel.

So along Homo1D directions in Quasi-3D simulations, only the exponential Kernel is available?

All the best
Alex


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-------- Original-Nachricht --------
Am 12. Mai 2024, 10:10, schrieb Sherwin, Spencer J < s.sherwin@imperial.ac.uk>:

Hi Alexander,

SVV was originally defined for special methods similar to the homogeneous expansions. The SH/PEM use of SVV came later and it is for these expansions we have developed the different kernels.

Spencer 

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On 12 May 2024, at 00:10, Alexander Schukmann <alexander.schukmann@protonmail.com> wrote:



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Hello everybody,

I am currently running Quasi-3D CG-SVV iLES with the IncNavierStokesSolver and noticed that the SVV PowerKernel is not activated/available for Fourier discretizations along homogeneous directions. However in the paper "Industry-relevant ILES of a high-performance road car via S/HPEM" (Mengaldo et al. 2021) it says:

"The current best practice in Nektar has been to use the "DG" kernel in general while employin the "power-law" kenel only along homogeneous directions in case periodic boundary conditions are present"

So does this mean the PowerKernel is only available if S/HP is also used along homogeneous directions? Why not use the DGKernel then? And how does one setup different SVV kernels for different spatial directions? If it DOES refer to the quasi-3D case, however, there seems to be an issue, since no output is given regarding SVV, if the "SpectralVanishingViscosityHomo1D" flag is set to "PowerKernel" within the session file.

Also I noticed that it seems to be impossible to activate SVV only for the S/HP discretizations in quasi-3D cases, i.e. without using SVV for the Homo1D directions, but vice versa it works.

All the best

Alex

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