Hello All and especially Prof.
 

Hello All and especially Prof. Jasak,

I am currently working on my MSc thesis and I would like to know something;
I cannot find any reference on the SFCD scheme and how it works. I can try to find out using the .C and .H, but my C++ knowledge does not extend that far I regret.
1) Does anyone have a reference or is anyone willing to share some thoughts/opinions about SFCD ?
2) Also, what is the main difference between SFCD and the Gamma scheme ? Please correct me if I'm wrong, Is the difference that the Gamma scheme contains a scaling factor (which is 2*beta_m in Jasaks paper(?)) and SFCD does not, or is it also in the blending function or other parts?

Best regards,
Bart

Hello Bart, All these schem
 

Hello Bart,

All these schemes are blended upwind-central type, using a limiter. The only true difference is the form of the limiter and its basis.

The original reference for SFCD is a PhD from Dr. Harry Ziman, from mid 1990-s at Imperial College London. Basically, the limited looks like MINMOD and you can revrese-engineer it from the code:


scalar phict = LimiterFunc::phict
(
faceFlux, phiP, phiN, gradcP, gradcN, d
);

scalar limitPhict = min(max(phict, 0), 0.5);
return limitPhict/(1 - limitPhict);


Here, phict is Phi-C-tilde (have a look at the Gamma paper) and the limiter is written out. For Gamma, the limiter is:

min(max(phict/k_, 0), 1) but k is re-scaled on the constructor to be between 0 and 1 (in reality is is 0-0.5).

k_ = max(k_/2.0, SMALL);

Enjoy,

Hrv

Thanks for the quick clarifyin
 

Thanks for the quick clarifying awnser, I'll see if I can get a hold off Dr. Ziman's paper.

What I don't get so far, k is equal to beta_m ? Then why is Phi-C-tilde limited ?
Is the limiting done to easily select between UD, blending or CD, or something a like ?

@PhdThesis{Ziman:PhD, autho
 

@PhdThesis{Ziman:PhD,
author = {Ziman, H.J.},
title = {A computer prediction for chemically reacting flows
in stirred tanks},
school = {Imperial College, University of London},
year = {1990}
}

Yes, it's all about automaticaly blending UD and CD (well, a second-order scheme of your choice) .

Hrv

Sorry, I do not do support wit
 

Sorry, I do not do support without a support contract. You simulation failed way before this point.

Hrv

Is SFCD a NVD scheme? Here it is states as a "General convection scheme"
How is it possible to understand from the OpenFOAM sources, is scheme TVD or NVD? I found only the directory structure:

Regards,

Alexander

Dear Dr. Jasak,

Your reply is very helpful for me to understand the Gamma scheme. However, can I ask you other several questions?

1, what does k_ stand for in the code you mentioned?

2, about the limiter function for gamma scheme, did you have any reference for it? I did not find any information about it from the literatures?

3, this questions is not linked to Gamma scheme, but I ask here:
in openfoam, the numerical fluxes on the inter-cell face are for primitive variables (e.g. U_f) or conservative variables (e.g. (rho*U)_f)?

Thank you so much!

OFFO

Dear Prof. Jasak,

I have some understanding about the limiter for Gamma function used in Openfoam. But I found there is still some difference compared with your Gamma Scheme paper. The scalar k_ should be the constant beta_m in that paper. The difference is:

Is what I am saying correct? Thank you for your any comments.

OFFO