Fluid enters and flows through a rectangular channel at x = 0 with no drug present in the fluid (i.e. C = 0). The free stream velocity V is uniform at x = 0. The bottom surface of the is coated with a drug between x = 0 and x = L (the shaded region in Figure Q4(c)) and the concentration along the surface is Csurf. Inside the channel, the concentration in the fluid above the surface is described by a cubic relationship as shown in Figure Q4(c,right). The height of the concentration boundary layer δc at the end of the channel is small relative to the height of the channel H, i.e. H >> δc. After the fluid passes the end of the coated surface at x = L, the fluid becomes well mixed and the concentration has the same value C∞. Determine an expression for the well mixed concentration C∞.
