抄録
This study investigates the influence of temperature-dependent physical properties in drag-reduced flow to clarify at which location temperature should be changed in order to contribute to drag reduction, by effecting wall heating so as to arrange a vertically and longitudinally "non-isothermal field" in channel flow. Flow characteristics and temperature profiles have been measured by an LDV system and a fine thermocouple probe. A difference in velocity profiles between the cases of T_w=44℃ and 48℃ has been observed : the former is distributed along the profile for drag-reducing flow, and the latter is similar to that for water as turbulent flow. Investigation of the effect of non-isothermal heating on drag-reducing flow revealed that the temperature dependent condition of flow and temperature field in the buffer layer (50<y^+<100) is an important factor for controlling heat transfer in the drag-reducing flow.
