A closed cylindrical drum of diameter 500 mm has its axis vertical and is completely full of water. In the drum and concentric with it is a set of paddles 200 mm diameter that are rotated at a steady speed of 15 revolutions per second. Assuming that all the water within the central 200 mm diameter rotates as a forced vortex and that the remainder moves as a free vortex, determine the difference in piezometric pressure between the two radii where the linear velocity is 6 m s.

A closed cylindrical drum of diameter 500 mm has its axis vertical and is completely full of water. In the drum and concentric with it is a set of paddles 200 mm diameter that are rotated at a steady speed of 15 revolutions per second. Assuming that all the water within the central 200 mm diameter rotates as a forced vortex and that the remainder moves as a free vortex, determine the difference in piezometric pressure between the two radii where the linear velocity is 6 m s.