EFFECT OF A SUPERSONIC COUNTERFLOW JET ON BLUNT BODY HEAT TRANSFER 
RATES FOR ONCOMING HIGH ENTHALPY FLOW

Vinayak Kulkarnia and K. P. J. Reddyb

UDC 536.25

Heat transfer reduction studies, in the presence of a 
supersonic counterflow jet from the stagnation point of a 60-deg apex 
angle blunt cone, are conducted in a free piston driven hypersonic 
shock tunnel, HST3, to verify the effectiveness of this technique 
for high enthalpy flows. For flow of Mach number 8 with stagnation 
enthalpy of 5 MJ/kg, it has been observed that the heat transfer rate 
at some location decreases initially with increase in the injection 
pressure ratio until the critical injection pressure ratio is reached. 
A forty-five percent reduction in heat transfer rate near the stagnation 
point has been measured for the critical injection pressure ratio, 
equal to 14.91. A further increase in the injection pressure ratio 
reduces the overall percentage heat transfer reduction. The dependence 
of fluidic spike length on percentage heat transfer reduction has 
been confirmed.

Keywords: hypersonic flow, drag reduction, free piston shock tunnel. 

aDepartment of Mechanical Engineering, Indian Institute 
of Technology Guwahati, Guwahati, India 781039; email: laser@aero.iisc.ernet.in 
bDepartment of Aerospace Engineering, Indian Institute of Science, 
Bangalore, India 560012. Published in Inzhenerno-Fizicheskii Zhurnal, Vo. 82, 
No. 1, pp. 3-7, January-February, 2009. Original article submitted June 28, 2008.