Abstract
The effect of a sphere on the local heat transfer to a turbulent boundary layer was examined. The diameters of the sphere used in this experiment were D = 12, 20, 30, 40, 50, 60, 70, and 80 mm. The boundary layer thicknesses where the sphere was placed were 60, 70, and 75 mm, corresponding to main flow velocity of U = 7.5, 10.0, and 12.0 m/s, respectively. The freestream turbulence level was less than 0.5%. The local heat transfer coefficient, mean velocity and turbulent intensity were measured. Surface temperature and surface flow pictures were obtained. The results showed (1) The local heat transfer coefficient distribution has a peak at 1.5D downstream of the sphere. (2) The peak value has a relation with Re number based on the sphere diameter. (3) Flow periodicity was not found behind the sphere on the plate.
