[firatwsen]

Hi Everybody

ı have a simple question.

I read from tutorials that "Second-Order Upwind – Uses larger stencils for 2nd order accuracy, essential with
tri/tet mesh or when flow is not aligned with grid; convergence may be slower." .

I did not understand actually what does it mean with "when flow is not aligned with grid". Does it mean, if you can not guess the flow direction and you can not mesh geometry according to flow direction (so you used tri/tet mesh), you should use second order upwind method?

Please help me

thanks