Question about bottom boundary layer in homogeneous fluid

[han]

Hi,

I'm trying to run a pure barotropic 3D model with ROMS. In the model, T and S are set to be constant (by TS_FIXED), no radiation flux, no wind forcing. And the model is driven by M2 tide at open boundary only. This experiment is used to find out the lateral circulation(imbalance between Coriolis and cross section barotropic pressure gradient, with some contribution from bottom friction) mentioned by Winant(2007).

The problem I have is related to bottom friction. I use UV_LOGDRAG with Zob=0.01. And when I plot the vertical structure of u-velocity, I found the whole water column follows the log profile. The friction is dominating. So, in a homogeneous fluid, how can I restrict the bottom boundary layer? By the way, I use
GLS mixing scheme with k-omega closure.

I attached the *h and *in file and an example of vertical u-velocity structure.

Thanks