Boundary$-$layer separation occurs when the shear stress at the surface becomes zero. Assume that a

polynomial representation for the laminar boundary layer of the form, $\frac{u}{U}=a+b+c{}^2+$

$d{}^3,$ where $=y.$ Specify boundary conditions on the velocity profile at separation. Find appropriate

constants, $a,b,c,$ and $d,$ for the separation profile. Calculate the shape factor H at separation.