Rayleigh problem with time-dependent plate velocity and shear stress

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UFeng
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Homework Statement


Consider the Rayleigh problem, but allow the plate velocity to be a function of time, V(t). By differentiation show that the shear stress, tau = du/dy*absolute viscosity, obeys the same diffusion equation that the velocity does. Suppose that the plate is moved in such a way as to produce a constant surface shear stress. What are the velocity profile and the surface velocity for this motion.


Homework Equations


I'm not sure that these are actually relavant but here is what I assume:

Shear Stress = - Absolute Viscosity*V0 / SQRT(PI *kinematic viscosity*t)

density*dv/dt = absolute viscosity*d^2v/dy^2 => simplified momentum eqn.




The Attempt at a Solution


I'm not sure how to even get started on this problem. Any suggestions or help would be appreciated. Thanks
 
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dianaku said:
did you solve the problem?
Welcome to the PF. :smile:

Their last post here was in 2009, so they are not likely to respond to you now. If you have a similar question, go ahead and start a new thread here in the Homework Help, Intro Physics forum and show as much of your work as you can. You should get good help that way.