Author(s)

Katsuya Kajiwara, Masayuki Anyoji

Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, Japan.

In this study, we experimentally investigate the effects of mainstream turbulence intensity (T_i) on a leading-edge separation bubble under low-Reynolds number (Re_c) conditions range of 2.0 × 10⁴ to 6.0 × 10⁴. We used a flat plate to fix a separation point at the leading edge. Also, we visualized the behavior of the leading-edge separation bubble using the smoke wire technique and Particle Image Velocimetry (PIV) measurement. Furthermore, we measured the effect of T_i on the turbulent transition process in the separated shear layer using a hot-wire anemometer. The results indicate that the bypass transition for large T_i causes the turbulent transition, and so accelerates the reattachment of the separated shear layer. The results show that the bypass transition promotes the reattachment of the separated shear layer to maintain the leading-edge separation bubble on the upper surface even at high angles of attack, increasing the stall angle.

Separation, Turbulence Transition, Fluid Dynamics

Kajiwara, K. and Anyoji, M. (2020) Turbulence Intensity Effects on a Leading-Edge Separation Bubble of Flat Plate Wing at Low-Reynolds Numbers. Journal of Flow Control, Measurement & Visualization, 8, 188-207. doi: 10.4236/jfcmv.2020.84012.