Numerical study on flow induced noise of flexible hydrofoil based on fluid structure interaction

t As flexible hydrofoil deforms too much under fluid impact, the hydrodynamic load was calculated by computational fluid dynamics (CFD) method and structural response was calculated by finite element method. A two-way fluid structure interaction numerical method was established. The steady flow field and pressure fluctuation of NACA66mod hydrofoil were obtained with the method under structural deformation, and numerical results illustrate that transition happens to the hydrofoil at attack angle of 4°~6° and Reynolds number of 7.5×105.Based on the fluctuation pressure, a flow induced noise calculation method was established with mode superposition method and acoustical boundary element method.Numerical calculation results show that main frequency peak of the flow induced noise reduces after transition; the main frequency and sound pressure level of the two components increase by 25 Hz and 3 dB with Reynolds number increasing by 1.5×105, respectively; flow noise depends on pressure fluctuation while vibration noise depends on structural natural characteristics as well as excitation force; for overall sound pressure level (SPL), the flow noise of hydrofoil is greater than its own vibration noise; vibration noise damps faster near the wall while flow noise damps faster in far field. © 2017, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.