Abstract
The effect of a spanwise traveling wave motion on a turbulent boundary layer over a flexible sheet was investigated. The test plate placed in wind tunnel had a flexible sheet section, where the traveling wave motion was generated by the vibration device. It enables the measurements for the higher amplitude and frequency compared to our previous measurements due to the loudspeaker. Velocity profile was measured with a hot-wire anemometry. Amplitude and frequency of the traveling wave motion were measured using two laser displacement sensors. The drag reduction ratio was estimated from the development of momentum thickness of the turbulent boundary layer over the flexible sheet section. The maximum drag reduction with the spanwise traveling wave motion could be obtained T^+=95 and a^+=27.
