[nathanricks]

Hello,

I'm trying to simulate the classical case of turbulent channel flow at Re = 180 with Ansys Fluent 15.0, using LES (with dynamic smag SGS model, and an in-house SGS model).

The simulation is running, and seems to give trends as expected, however we are seeing an overprediction in the mean streamwise (x) velocity - ~21m/s compared to ~18m/s in the literature.

Does anyone have any experience with this particular case in Fluent, and can give me some hints/point me towards a tutorial, etc?

Some of the major setup points include:

- Periodicity in the x (streamwise) and z (cross-stream), with walls in the +/- y direction

The periodicity was defined in fluent, using modify zone. The pressure gradient is defined as -1 (from dP/dx = density*(u_fric)^2), with flow direction = [1,0,0] - this is one of our concerns, is this correct for Fluent?

- CFL and wall y+ < 0.5
- Grid and domain defined consistent with literature
- Flow initialised using k-epsilon RANS, and then init-instantaneous-vel

If any more details would be helpful I'd be happy to give. Any help would be much appreciated!

Thank you in advance,
Nathan.