Base pressure at supersonic speeds in the presence of a supersonic jet

摘要

The effects on base pressure of jet Mach number, free streamReynolds number and jet to base diameter ratio have been investigatedexperimentally.It was found that, for jet stagnation pressures greater than thatrequired for the nozzle to reach its design Mach number, an increaseof jet Mach number reduced the base pressure. Similarly the basepressure increased with increase of the ratio of jet diameter to basediameter and, at nigh jet stagnation pressures, base pressures higherthan free stream static pressure were found. The base pressurewasindependent of frek: stream Reynolds numbers greater than 2 x 10[to the power of 6] perfoot but increased with reduction of Reynolds number below 2 x 10[to the power of 6] perfoot.Unsteady wave patterns were found when the jet Mach number didnot differ markedly from the free stream Mach number and the jet hadjust reached its design conditions.