A torpedo 533 mm dia and 6700 mm long is to travel in water at 28 m/s. A model of 1/5 scale is to be tested in a wind tunnel. Air speed in the tunnel should not exceed 110 m/s to avoid compressibility...

A torpedo 533 mm dia and 6700 mm long is to travel in water at 28 m/s. A model of 1/5 scale is to be tested in a wind tunnel. Air speed in the tunnel should not exceed 110 m/s to avoid compressibility effect. If air can be pressurised with temperature remaining at 20oC determine the minimum pressure required. Dynamic viscosity is not affected by pressure. If the drag force at this condition on the model was 618N, Determine the drag on the prototype.