جستجوی مقالات مرتبط با کلیدواژه "ال.ای.اس" در نشریات گروه "مکانیک"

This study examines the accuracy of three different methods for calculating the aerodynamic noise of the NACA-0012 airfoil in a homogeneous shear flow. The strength of flow vortices is crucial in aeroacoustic calculations, and it can be modeled more cost-effectively using the k-ω SST method or directly simulated up to 90% using large eddy simulation (LES) with higher cost. Additionally, a hybrid method called IDDES, which offers moderate accuracy and cost, is also considered in this research. The primary sources of noise generation identified are vortex shedding from the laminar boundary layer and its interference with the trailing edge, as well as Tollmien-Schlichting waves. Experimental data of the sound pressure level (SPL) in 1/3 octave is used to validate the accuracy of the methods. The results indicate that LES and IDDES show the closest agreement with the experimental data, with LES showing better accuracy. Furthermore, when studying the intensity of sound attenuation with distance, it is observed that the rapid attenuation of small vortices in LES leads to similar SPLs as IDDES after a distance of 1.2 meters. Moreover, since IDDES does not require strict regulations for creating a near-wall grid, it reduces the computing mesh by approximately 41% with less than 2 dB of error. This finding suggests that in similar applications, the IDDES method can be used as a suitable approximation instead of LES to expedite calculations and conduct parametric studies