[callumso]

Hi,

I read from the user guide that the gradient scheme could be just Gauss plus an interpolation scheme. Then I tried to do something as below:

gradSchemes
{
default Gauss linear;
grad(p) Gauss limitedLinear 1;
grad(U) Gauss limitedLinear 1;
}

And I got the following error message:

--> FOAM FATAL IO ERROR:
wrong token type - expected word, found on line 27 the label 1

file: /home/ttjs3/OpenFOAM/ttjs3-2.1.1/run/duct1/system/fvSchemes::gradSchemes::grad(U) at line 27.

From function operator>>(Istream&, word&)
in file primitives/strings/word/wordIO.C at line 74.

FOAM exiting

I don't know what kind of parameter should follow "Gauss limitedLinear 1" in such a case. I am still virtually illiterate about C++ and can't really understand how to dig out the information in the relevant code as I am really baffled by all the class definitions, selectors and so on...

Could someone give me on hint on what I have done wrong in this setting? Thank you very much.

Actually I got another problem with the second order backward time scheme. I am testing it on a simple straight duct case.

It's just never stable...and I don't know why. My CFL number is as low as 0.001. Increasing it further just made the simulation blow up in a few time steps. Reducing it can help to make the simulation run longer, but still not stable.

Does anyone have any experience on this backward second order scheme? Thank you.

Best Regards,
Callum