(Solved):
The steady, laminar boundary layer over a fat plate can be stabilized at constant thickness by suc ...
The steady, laminar boundary layer over a fat plate can be stabilized at constant thickness by suction of fluid at the surface of a porous plate. This is a technique aften used to prevent flow eeparation. Consider such a flow as shown in the figure below. The suction velocity (in the y-direction) is uniorm at Va along the plate (in the direction shawn). At a certain distance from the ieading edge of the plate, the boundary layer thickness (d) and velocity profie (ufy)) become constant (fully developed), and are no longer a function of x distance. In this fully developed region, assuming constant surface temperature (Tb? ) and a freestream velocity af (Ux?), and incompressible flow, apply differential form of Conservation of Mass, Momentum and Energy equatons to find expressions for: a) (10 pts) The boundary layer profle (u(r)/U??) (define B.C. 's at y=0 and y== ) Applying B.C. at edge of BL as y=w allows for a simple solution. b) (5 pts) The skin friction coefficient (CC?) c) (8 pts) The temperature protile (Tn??Tn?T(y)?Tv??) (Neglect viscous dissipation) d) (5 pts) The Nusselt number ( Nuu2??) e) (4 pts) The velocity ( ( ) and thermal ( 6j) boundary layer thickness (u(s) = ggw of freestream velocity) f) (2 pts) if the fluid has a Prandtl number equal to (Fr =1 ), comment on the relationship between the velocity and boundary layer thickness based on the result from part e. Hint: For x??(y)+Av?(y)=0 the solution is: m(y)=C1?e?1y+C2?