Computational aeroacoustic characteristics of an airfoil at higher Reynolds number

Abstract

Noise generation has long been one of the major problems associated with fluid flow over airfoils. Over a period of time, many mechanisms and sources of noise generation for flow over airfoils have been identified experimentally and numerically. There have been gaps in understanding aeroacoustics of airfoil, especially at higher Reynolds numbers. Hence the objective of this work is to carry out computational study on the aerodynamics characteristics and find out various noise sources at a Reynolds Number of 6.2 ×105 for NACA0012 airfoil. At this Reynolds number, various flow features such as laminar-turbulent transition, laminar bubble creation and shedding, separation and reattachment of the boundary layer can be encountered. These flow phenomena can severely affect the aerodynamics characteristics and can also modify the acoustic characteristics. The computations are carried out using the commercial CFD software, ANSYS Fluent with Large Eddy Simulation model for turbulent flow and Ffowcs-Williams & Hawkings model for acoustic prediction. The sound pressure level of noise is obtained at various angles for a receiver location of 5.5 times cord length of the airfoil. The data obtained from the numerical solution is validated with the available experimental data and found to be in good agreement.