An experimental study of boundary-layer transition induced vibrations on a hydrofoil

• DOI: 10.1016/j.jfluidstructs.2011.04.002
• Publication Date: 2011-05-01T05:55:39Z
• Authors: Antoine Ducoin; Jacques André Ast...; Marie-Laure Gobert
• Keywords: Vortex shedding; Laminar sublayer; Laminar-turbulent transition; Kármán vortex street; Natural frequency; Vortex-induced vibration

In this paper, we investigate through an experimental approach the laminar to turbulent transition in the boundary-layer flow along a hydrofoil at a Reynolds number of 7.5 × 105, together with the vibrations of the hydrofoil induced by the transition. The latter is caused by a Laminar Separation Bubble (LSB) resulting from a laminar separation of the boundary-layer. The experiments, conducted in the hydrodynamic tunnel of the Research Institute of the French Naval Academy, are based on wall pressure and flow velocity measurements along a rigid hydrofoil, which enable a characterization of the Laminar Separation Bubble and the identification of a vortex shedding at a given frequency. Vibrations measurements are then carried out on a flexible hydrofoil in the same operating conditions. The results indicate that the boundary-layer transition induces important vibrations, whose characteristics in terms of frequency and amplitude depend on the vortex shedding frequency, and can be coupled with natural frequencies.