A steady laminar boundary layer is formed over a flat plate as shown in the figure. The free stream velocity of the fluid is U0. The velocity profile at the inlet a-b is uniform, while that at a downstream location c-d is given by
u=$U_{0}\left [ 2\left ( \frac{y}{\delta } \right ) -\left ( \frac{y}{\delta } \right )^{2}\right ]$
The ratio of the mass flow rate, mbx, leaving through the horizontal section b-d to that entering through the vertical section a-b is