The velocity profile for a film of liquid flowing down a vertical wall is given by
U = (?g/?)·(Lx – 0.5x2)
Where L is the thickness of the film, u is the downward velocity, xis the distance perpendicular to the wall and are the liquid density and viscosity.
• Sketch the velocity profile.
• Show that the average velocity is 2/3 the maximum velocity.
• Find the volume flow rate for a layer of water 5 cm thick flowing down a wall 200 cm wide at a temperature of 45oC.