An Experimental Investigation of New Parameters for Predicting Turbulent Heat Transfer

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In their investigation of boundary layer heat transfer in the presence of very high free-stream turbulence, Maciejewski and Moffat (1990) conclude that the RMS value of the streamwise turbulent fluctuations, u', plays a dominant role in determining the heat transfer coefficient, h. However, for the set of experiments that they performed, the value of u' was highly correlated with the value of the RMS turbulent fluctuations normal to their heat transfer surface, v'. The primary goal of the proposed research is to establish a set of boundary layer flows in the presence of high free-stream turbulence for which v' may be varied independently of u' in order to test by means of experiments the hypothesis that v' and not u' determines h. This same hypothesis will also be tested by measuring the individual components of the turbulent fluctuations instantaneously, using the hot-wire techniques suggested by Blair and Bennett (1987), and attempting to correlated them with the instantaneous surface heat flux, which will be measured using a technique described by Mancuso and Diller (1991). Measurements of the turbulent heat flux and the turbulent shear stress will also be made for each of the free-stream test conditions in order to test the hypothesis that v' is independent of u'v' for boundary layer flows in the presence of high free-stream turbulence.