I am doing simple laminar pipe flow with heat transfer. I assume the answer is no, but I am going to ask anyway.

I want to compare pipe flow with and without the streamwise second derivative in order to investigate Peclet number effects. Is it possible to turn off the streamwise second derivative in one of the directions?

Dear S.

In principle, No. However, if you setup the problem with anisotropic thermal conductivity you should be able to set the axial conductivity to 0.

Have you read the paper by

Hennecke, D.K. (1968), "Heat Transfer by Hagen-Poiseulle Flow in the Thermal Development Region with Axial Conduction", Wärme-und Stoffübertragung, Vol. 1, pp. 177-184.

or try this link,

http://www.nea.fr/html/science/repor.../chapter10.pdf

Opaque

Thanks for the link to the paper. I guess I am doing something a little more complicated than just pipe flow, but nonetheless I needed streamwise second derivatives off to make a comparison.

More importantly, thank you for this clever trick! It is obvious, but I never thought of doing that. Thank you!

S

Also, what about turning off the streamwise second derivative for the momentum equation?