F • CONVECTIVE HEAT TRANSFER IN GASES 



0.4 per cent turbulence in the supply chamber. Fig. F,18a, F,18b, and 

 F,18c show the results [56] of increasing the supply turbulence to 9 per 

 cent for M^ = 1.90, 2.70, and 3.65, respectively. It is immediately con- 

 cluded that: (1) the effect of cooling in delaying transition decreases with 



10 



2 6 

 X 



0) 



Trip size 



O No trip 



X 0.0005 in. 



D 0.001 in. 



A 0.002 in. 



ReeQt trip= 1.62 X 10* 

 Ree/in. = 0.54 X 10* 

 Te = 312°R 



0.5 



0.9 



1.3 



1.7 



Tw/Te 



Fig. F,19a. Effect of roughness on transition with cooling. 

 Me = 1.90. Wire trips at Re^ = 1.62 X 10«; 10° cone. 



increasing turbulence, (2) the effect of supply-tunnel turbulence in pro- 

 moting transition decreases as Mach number increases. The second con- 

 clusion is again drawn from Fig. F,18d, which is a cross plot of Fig. F,18a, 

 F,18b, and F,18c for zero cooling. The ordinate of Fig. F,18d is the ratio 



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