286 Forced Convection of Heat from Pair of Heated Wires. 



and 3, are plotted in fig. 4 as ordinates against the corre- 

 sponding separation of the wires as abscissae. In general, it 

 is to be anticipated that such maxima will be less in the case 

 when both wires are heated than when the first wire alone is 

 heated, as in the latter case no appreciable cooling effect of 

 the second wire as a direct convection effect due to the im- 

 pressed stream is present to reduce the heating effect arising 

 from convection of heat from the first wire to the second 



8 



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 UJ 



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W A 













X {LEADING WIRE 



I HEATED 

 1 BOTH WIRES 

 ^ 1 HEATED 







MAXIMUM INCREASE of F 



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E 



Fi&4. 





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2 4 6 



DISTANCE BETWEEN WIRES (CMS). 



8 



wire. The results shown are in agreement with this antici- 

 pation, except when the wires are separated by distances 

 of from 2 to 4 cm. For such distances the maximum attained 

 when both wires are heated is greater than the corresponding 

 maximum when one wire alone is heated. In these cases, the 

 distances apart of the wires are such that, owing to the 

 impressed stream, the resultant convection from the first wire 

 results in the region about the second wire becoming heated 

 above that ruling in the absence of flow ; thereby the velocity 

 of the free convection current arising from the second wire 



