Method for fneq reconstruction among wallfunction parameters in Channel 3D

[yx19971028]

Hello everyone,
In the example of channel3D in turbulence,I want to ask what is the NO2: regularized second order finite Differnce in the method for fneq reconstruction among Wallfunction parameters? Is there any relevant paper?
Thank you,
Yours sincerely,
Xu Yang.

[stephan]

Dear Xu Yang,

thanks for your question.

For wet-node boundary approaches in general, please see the evergreen book by Krüger et al. ‘The Lattice Boltzmann Method: Principles and Practice’ from 2017.

As far as I know, there’s no explicit reference for the procedure labeled as ‘fneqMethod=2’.
Anyway, I’ll try to explain its name term by term:
(1) regularization (in the sense of the regularized lattice Boltzmann collision scheme) means that we reconstruct the fneq’s from the non-equilibrium momentum flux (named ‘Pi’) which in turn can be approximated via the rate of strain tensor according to CE analysis.
(2) second order finite differences are used for computing the velocity gradient which is necessary for the strain rate in (1).

For implementational details, please see https://www.openlb.net/DoxyGen/html/dc/dbc/wallFunctionBoundaryPostProcessors3D_8hh_source.html from line 760 onwards.

BR,
Stephan

[yx19971028]

Hello Stephan,

Thank you for your reply.

Yours sincerely,
Xu Yang.

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