A STUDY OF FREE CONVECTION BOUNDARY LAYER OSCILLATIONS AND THEIR EFFECTS ON HEAT TRANSFER

摘要

Wave length, wave speed, and wave amplitudes of artificially induced oscillations in a free convection boundary layer on a vertical, isothermal, flat plate were measured with a Zehnder-Mach interferometer. It was found that, as the oscillations amplify in their movement up the plate, the wave energy increased more rapidly in the outer layers of the boundary layer than in the layers close to the wall. When the wave energy in the outer layers became sufficiently high transition to turbulence began. It was also observed that the time averaged heat transfer coefficient for the oscillating boundary layer was the same as the theoretical steady state value, within the range of the experimental error.