[Bollonga]

Hi everybody,

I'm trying to simulate an atmospheric boundary layer (ABL) flow around an inclined flat plate near the ground. I'm not developping the whole boundary layer but using velocity, k and epsilon profiles at the inlet with UDF's (there's no option to use turbulence intensity and turbulent length scale UDFs).

I've used a logaritmic profile for velocity:

u(h)=Uref*K*log(h/h0)

Uref=reference velocity (10 m/s)
K=constant (0.1866)
h0=roughness height (0.03 m)

I defined the turbulence intensity and turbulent length scale (TLS) profiles to get the k and epsilon profiles:

TI(h)=1/log(h/h0)

TLS(h)=Lt*(h/ht)^alpha

alpha=constant (0.4947)
ht=reference heigth (200 m)
Lt=reference TLS (300 m)

k=(3/2)*(Uref*TI)^2

TI from former TI profile equation

epsilon=C_mu^(3/4)*k^(3/2)/TLS

TLS from former TLS profile equation
C_mu=constant

Below h_min=1.5 m all profiles have a constant value equal to u(h_min),k(h_min) and epsilon(h_min).

I've initialized from the inlet but the issue is that with these profiles I get turbulent viscosity limitation from the very beginning. Even if I change the TVR limit to 10e15 limitations is reached very soon.

Does anybody have experience simulating atmospheric boundary layers?
Any advice on how to avoid this limitation?
Is it a matter of mesh density? Cause I cannot go beyond my current 2 million elements mesh... And I've seen some meshes in literature that are not very dense.

I post a picture with all the profiles involved in the simulation and some mesh screenshots.