QUESTION 9
As shown in the figure, a sonar array is towed behind a towing boat. The drag force of the sonar array is to be studied in a water tunnel at a scale model (model 1/4 the size of the prototype).
The drag force (D) is assumed to be a function of the speed of the ship (V), the density and viscosity of the fluid ($\rho$, $\mu$), and the diameter of the sonar array (d).
(1) Give the dimensional analysis to the problems using the variables listed.
(2) If the prototype towing speed is 3 m/s, determine the water velocity in the tunnel for the model tests.
(3) If the model tests of part (a) produced a model drag of 900 N, determine the drag expected on the prototype.
Fig. 5 Towing sonar