Ablood oxygenator consists of several permeable rectangular plates having length l and width w. a thin film of blood with uniform ud thickness h flows at a constant rate vertically down the wall of each plate. the film surface is exposed to air at atmospheric pressure and no shear stress applied to the surface (i. c., blood film surface and surrounding air interface

a) derive and sketch the velocity profile within the film.
b) find and sketch the distribution of shear stress in the film.
c) calculate the flow rate of blood.