Noise Estimation of NACA 0012 Airfoil Using DES Method

An airfoil is used in many engineering applications for its ability to create high aerodynamics performances compared to other shapes. However, airfoils also produce annoying noise, and consequently has degraded its usage near the residential area. The study on airfoil noise prediction is very challenging, either experimentally or numerically. Background noise and identifying detailed noise sources are the common problems in experimental works while accurate prediction of small fluctuating pressure requires huge computational resources for numerical noise prediction. This study evaluates the performance of Detached Eddy Simulation (DES) as the turbulent modelling approach in predicting the noise source of a NACA 0012. The noise calculated from DES is compared with RANS and the experimental results. The study showed that the DES turbulence model is able to capture peak frequency at 300 to 600 Hz, similar to the experimental result. Additionally, DES provides better accuracy than RANS turbulence model by eliminating the sudden peak captured by RANS at a higher frequency. However, DES turbulence model still does not capture the good trends in the high-frequency region above 800 Hz because this turbulence model is a hybrid of RANS and still becomes the dominant influence in the DES calculation in the near-wall region.