diff(u(z),z,z)=g*S/Az (Barotropic pressure gradient vs friction equation) where S=Diff(eta(x)) or surface slope
bc=Az*D(u)(z)=0,Az*D(u)(-H)=tau/(Az*rho)=Cb*u^2(z)/Az
how can I solve and plot the for different depth z=-20 to 0
and Az=0.0010,Cb=0.0025,S=-0.000001
So how can I find the u(z)
and plot the graph of u(z) (velocity) against z (depth)
