TY - JOUR
TI - Decay of supersonic rectangular jet issuing from a nozzle with diagonal expansion ramps
AU - Bogadi Surendra
AU - Sridhar B T. N.
JN - Thermal Science
PY - 2019
VL - 23
IS - 6
SP - 3929
EP - 3940
PT - Article
AB - This paper addresses the effect of diagonal placement of expansion ramps on  the decay characteristics of a supersonic rectangular jet. The diagonal  placements of ramps induce additional vortices near the nozzle exit apart  from the corner vortices emanating from the rectangular corners which is  further enhances jet decay. A Mach 1.8 rectangular jet issuing from a  converging-diverging nozzle of aspect ratio 2 and Reynolds number 1.861×105 is  considered for the study. To avoid the losses in divergent section, the  shape of cross-section from the throat was maintained rectangular. Numerical  simulations and Schlieren image study were carried out to validate the  experimental results obtained from total pressure data. Both experimental  and numerical studies show that the expansion ramps played a significant  role to enhance decay rate. The ramps placed on the minor side caused  maximum supersonic core length reduction indicating accelerated decay. This  minor side ramps were found to be more effective at over-expansion  conditions whereas the major side ramps for under-expansion conditions.  Also, both experimental and numerical studies have shown that shock waves  are rendered weaker by the minor side placement of ramps at all expansion  levels.