The pressure drop between the entrance and exit of a 150 mm diameter 90° elbow, through which ethyl alcohol at 20°C is flowing, is to be determined with a geometrically similar model. The velocity of the alcohol is 5 m/s. The model fluid is to be water at 20°C, and the model velocity is limited to 10 m/s. (a) What is the required diameter of the model elbow to maintain dynamic similarity? (b) A measured pressure drop of 20 kPa in the model will correspond to what prototype value?