Indian Journal of Physics and Proceedings of the Indian Association for the Cultivation of Science November 1953

(I) where H is the rate of heat dissipation per unit area of the surface of the hot cylinder immersed in a moving fluid V is the fluid velocity the index Now at National Physical Laboratory of India New Delhi az"534 D. G. Kapadnis n is a constant and b and c are functions of the characteristic dimension of the cylinder immersed and of the excess of temperature of the cylinder over that of the [...] The accuracy of the observations was tested by plotting for each vessel this family Of straight lines corresponding to the various temperatures and in this way a check was obtained in the determination of the constant function b. The values of b obtained in this manner are recorded with the excess of temperature and the diameter of the cylinder in Table III. [...] The slope of each line gives the value of the forced convetion constant function b for the corresponding value of the excess of temperature of surface of the hot c#ilinder over that of the surrounding Stream of air. [...] 3 The values of the constant function b are therefore plotted against the excess of temperature of the surface of the cylinder over that of the surrounding stream of air for different cylinder diameters (figure 3) in order to get the various values of 0. It is seen from the values of 3 obtained in this way that /(3 is very nearly independent of the temperature. [...] In these investigations the temperature of the air-stream was measured at a considerable distance from the surface of the cylinder because it is welknown from theory and experience that at the very surface of the cylinder the temperature of the air-stream is not different from the surface temperature.