The effects of Mach number on the development of a subsonic rectangular jet

Jntroduct i on A subsonic jet of air emanating from a rectangular nozzle of an intermediate aspect ratio has been investigated u sing hot-wire anemometry. The purpose of this investigation is to extend our knowledge of a rectangular jet from incompressible to compressible flow. Results of the hot-wire measurements show that a compressible sub- sonic r ectangular jet behaves similar to an incompressible jet. It exhibits three dis- tinct regions c haracterized by the decay of the mean axial v elocity along the axis of the jet. These three r egions are a poten- tial core region. a two-dimensional type region, and an axisymmetric type region. The principal effect of increasing the Mach number of the rectangular jet was found.to be the extension of the two-dimensional type region, and the jet behaves more nearly Ilke a two-dimensional jet at higher Mach numbers.