AERODYNAMICS OF HIGH SPEED GROUND VEHICLES IN TUBES

The drag coefficients and measurements of static wall pressure for tube-vehicle transportation systems are presented. The experimental results are from a test facility that launches models at 200 to 400 mph into a precisely aligned tube (one inch diam and 100 feet long test section). The models simulate a full-scale vehicle operating with a Reynolds number of 10 to the fifth power in a tube seven miles long. With a blockage ratio of 0.56, a choke flow in the gap between the vehicle and wall requires velocities above 300 mph. The wake region is shown to be an important factor on the vehicle drag. By opening or closing a set of vents behind the vehicle, the drag is modified substantially. The static pressure measurements provide information about the compression and expansion waves in the tube. Details of the pressure in the immediate vicinity of the vehicle are shown.