em_les: how can we set the environmental wind?

[Wantingggg]

The description of em_les is the:

"This test case produces a large-eddy simulation (LES) of a free convective boundary layer (CBL). The environmental wind (or the initial wind profile) is set to zero in this default case.The turbulence of the free CBL is driven/maintained by the surfaceheat flux, which is specified in the namelist as tke_heat_flux=0.24(in MKS units)"

Can we set the tke_heat_flux=0, and let the flow to be driven by the environmental wind that always exist (instead of the initial wind profile)?

Thanks,
Wanting

 

[Ming Chen]

Wanting,
The ideal LES case is designed for free convective PBL, which is driven by the surface heating specified in namelist.
You can set tke_heat_flux = 0, and manage to maintain a constant wind field. In this case I suppose that the large eddy would be forced by surface stress. However, I am concerned that the environmental wind field will impose influences along the boundary, and such influences will propagate into the interior of the model domain, eventually affect the LES simulation.