MaplePrimes - answers and comments on Question, Would you please help me as I am a new maple user

Perhaps more explanation needed

edgar — Tue, 09 Jun 2009 18:24:43 Z

diff(u(z),z,z)=g*S/Az The items on the right are NOT functions of z ? So this says the second derivative of u(z) is a certain constant? bc=Az*D(u)(z)=0 So this says the derivative of u is zero [and thus u itself is conatant]? Looks like I cannot see your actual meanings! --- G A Edgar

Dear G A Edgar would you

muslem760 — Thu, 11 Jun 2009 12:50:28 Z

Dear G A Edgar

would you please let mem know your mail address so that i can mail you the problem

thanks for your response.

Regards

Uddin(mmu_ims76@yahoo.com)

please help me

muslem760 — Thu, 11 Jun 2009 13:30:02 Z

The problem was like this

the Barotropic pressure gradient vs friction equation is given like G*diff(eta)(x),x)=Az *diff(u)(z),z,z) where diff(eta)(x)=S

so now the balance equation becomes diff(u)(z),z,z)=(g*S)/Az (and here z = depth), u= velocity) and right side all are constant

it is given that

when z=0, that is in the surface Az*diff(u)(z),z)=0, and when z=-H then Az*diff(u)(z),z)=tau(b)/rho or (bottom friction/water density)

Again it is given that tau (bottom friction term)=(Cb*u^2)*rho

so we get diff(u)(z),z)=Cb*u^2(z)/Az

Finally the solution is

u(z)=(g*S*z^2)/2*Az - (g*H*S^2)/2*Az+sqt(g*S*H/Cb)

now if I take Az=0.0010, Cb=0.0025, S=-0.000001, g=9.8, H=20, and z=-20 to 0 ( plot) for different value of Cb and Az

another value for Az=0.005, Cb=0.001

I think now you can help me in solving the equation in maple

regards

Muslem Uddin

I have given more explanation of my problem, please help me

muslem760 — Sat, 13 Jun 2009 11:11:06 Z