It is desired to predict the drag on a sonar transducer, based on the results obtained in wind tunnel tests. The prototy

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It is desired to predict the drag on a sonar transducer, based
on the results obtained in wind tunnel tests. The prototype
consists of a one-foot-diameter sphere that must be dragged at a
speed of 5 knots (nautical miles (Nmi) per hour) in seawater. The
model is 6” in diameter. Determine the speed required for the test
in air. If the drag on the model under test conditions is 5.58 lbf,
estimate the drag acting on the prototype. 1 Nmi = 6080 ft. For
seawater ρ= 1.98 slug/ft3 and υ= 1.4x10-5ft2/s. For air ρ= 0.00238
slug/ft3 and υ= 1.56x10-4ft2/s.