Abstract
Unsteady measurement of convective heat transfer was performed to a water flow in a horizontal circular pipe using a high-speed infrared thermograph. The test surface was fabricated from a 22μm thick titanium foil coated with black paint. The removable turbulence promoter was attached at entrance of the pipe. From the time-series data of the heat transfer distribution, we could obtain the rms value of fluctuating heat transfer coefficient and mean spanwise wavelength of the thermal streaks and the mean period of heat transfer fluctuation.