(a) To determine the drag on the hull of a ship, a 1/50 scale model was used. The model was designed to work based on Froude number criteria, while the prototype ship was planned to work with the speed of 9.25 m/s. If the water for the two experiments has the same properties, and negligible shear drag, find: (i) At what velocity should the model be towed? (3 marks) (ii) What is the drag ratio of the prototype against the model? (7 marks) (b) The required power, P, to drive a fan depends upon its diameter, D, the rotational speed, , the fluid density, , and the flowrate, Q. Use D, , and as repeating variables to find a set of pi terms.

(a) To determine the drag on the hull of a ship, a 1/50 scale model was used. The model was designed to work based on Froude number criteria, while the prototype ship was planned to work with the speed of 9.25m/s. If the water for the two experiments has the same properties, and negligible shear drag, find: (i) At what velocity should the model be towed? (ii) What is the drag ratio of the prototype against the model? (7 marks) (b) The required power, P, to drive a fan depends upon its diameter, D, the rotational speed, , the fluid density, , and the flowrate, Q. Use D, , and as repeating variables to find a set of pi terms. (15 marks)