Hello,everyone.

I wonder if the roughness height(z0*) influences the term with highlight.

Thank you.

Hi YuXuan,

Yes, the bottom roughness height z0* have effects on the vertical eddy viscosity “Av” in the highlighted term.

For the details, please refer to the EFDC+ theory document which can be downloaded here:

Indeed, it is used firstly to estimated the drag coefficient “Cb” from equation 2.30, and then bottom friction velocity in equation 2.29. The bottom friction velocity then is used for the lower boundary condition of the turbulence intensity “q” in equation 2.23 (see equation 2.28). Finally, the eddy turbulent viscosity is calculated by the equation 2.13 which is dependent on the value of the turbulent intensity “q”.

Sincerely,

Kien