42 



ancy between the unheated profile and the Blasius 

 solution may be due to small pressure gradient 

 effects. 



Mean temperature profiles and wall temperature 

 distributions measured for values of T„(Xj,gf)-T„ 

 =5°F are compared to relevant solutions of the 

 boundary layer equations in Figure 19. These 

 similar solutions were obtained by Runge-Kutta 

 integration of the coupled momentum and energy 

 equations assuming variable viscosity and thermal 

 conductivity. Their development is not shown here. 

 The error bars shown in Figure 13 represent the 

 maximum measurement error. Agreement between the 

 measured and predicted profiles is reasonable con- 

 sidering the fact that the wall temperature cannot 

 be monitored or maintained near the leading edge 



due to equipment limitations. The thermal boundary 

 layer near the leading edge is too thin to make 

 temperature profile measurements with the hot film 

 practical. The first indication of the wall tem- 

 perature is thus provided by the thermistor imbedded 

 in the plate surface at x = 1.2". The heater 

 nearest the leading edge is located at 0.71" < x 

 < 0.96". The actual wall temperature thus rises in 

 some unknown manner from T„-T„ = at the leading 

 edge to a value near the desired local wall tem- 

 perature at X - 0.71". These limitations are more 

 severe for increasingly negative values of n, which 

 require large temperature differences near the 

 leading edge, and may be the cause of the discrep- 

 ancy between theory and experiment seen in Figure 

 13 for the attempted n = -0.5 profile. 



1.0 



0.8 



0.2 



1 2 



V 



J 



200 400 600 800 



1.0 



0.4 



0.2 



1 2 



I? 



8r 



~i 2 



2 4 6 



X {inches) 



200 400 600 



800 



FIGURE 13. Mean temperature profiles for 

 power law wall temperature distributions, 

 Tv,(x) - T„ = Ax". 



10 



V 







2 4 6 



X (inches) 



200 400 600 800 



