Exception I guess is if you're using linearUpwind limited

linearUpwind limited is as short way to say:

you can also say: linearUpwind corrected;

for the vectorized versions linearUpwind (linearUpwindV) you want to use grad(U) for example

finally, linearUpwind inherits from the NVD classes in FOAM

Oh true, forgot about those

which need the definition of the gradient

Yeah just seems like it wouldn't hurt for it to default to just grad(X) where X is the field you're specifying the scheme for

doesn't really matter in the end though

Extra specificity doesn't hurt I suppose when bytes are so cheap

Well you could avoid these confusions just by using the limited or corrected option

if you do:

linearUpwind grad(U);
...
snGrad(U) limited;

then the limiting is also applied right? Or is it not?

I assumed that it was

But never bothered to check

On the gradient, not on the divergence

On the divergence it will go to gradientSchemes and pick what you defined for grad(U) and then face interpolate

https://www.wolfdynamics.com/wiki/tipsandtricks.pdf Look at slide 21

That's not a justification. It could very well be a typo.

Yeah sure - just thought he wanted the link. Well in the beginning the mention "It is based on my personal experience". Otherwise i guess that people seem to agree that it is typo.

Hi I am modelling flow past a sphere in openFoam and would like to simulate the same in steady state...I tried using kw-sst-model but for a reynolds no of 400000 the drag coefficint is coming out to be 0.3 which does not match with the literature at all...which model should I use for such cases?

I am using steady state RANS for now

something like reynolds stress model or Spalart-Allmaras might be worth looking into

I would highly assume that Re=4e5 would require a transient simulation with Co<1. The setup it self is unsteady by nature. You will probably have to track the drag-coefficent over a certain time and average.

Hi guys, I've once again thought a little bit more about the turbulence handling in my simulation. I have compared both highRE and lowRE modelling of the wall and wanted to clear something up, because on the forums there is conflicting information and a lot of stuff thrown around. If I want openFOAM to correctly handle the wallfunctions (.com and v2506) how do I defne it correctly?

Curently for the highRE I have:

k
kqRWallFunction with the internalfield value of 0.5

nut
nutkWallFunction with uniform 0

omega
omegaWallFunction with internal field of 2.7

for the lowRE case:

k
kqRWallFunction with uniform 1e-10

nut
nutUSpaldingWallFunction with uniform 0;

omega
omegaWallFunction with uniform 1e-4;

Does this go in the right direction? I am just a little confused with all the information on the web that conflicts itself and is from all over the years. Would appreciate it.

Kqr wall function is basically just a zero gradient BC

That's good for high re, but had for low re

I think, I'll double check

Both Spalding and omega wall function are fine for low re and high re