Trailing Edge Noise Prediction from NaACA 0012 & NACA 6320 Using Empirical Pressure Spectrum Models
IOSR Journal of Applied Physics (IOSR-JAP), e-ISSN: 2278-4861. Volume 10, Issue 2, Ver. I (Mar. – Apr. 2018), Pp. 33-46
14 Pages Posted: 23 Apr 2018
Date Written: March 17, 2018
Trailing edge of airfoil represents one of important sources in aerodynamic noise production. In this paper, the numerical computation of sound pressure using quasi empirical model and wall pressure spectrum models based on external pressure gradients was conducted for NACA 0012 and NACA 6320 airfoils. The development of boundary layer thickness and displacement thickness for different chord lengths and Mach numbers with varying angles of attack, are illustrated for NACA 0012. The sound pressure levels evaluated between 00 to 60angles of attack and at constant chord length of 1.2m using BPM model showed change of ~5dB in peak amplitude. The maximum test velocity and chord length used for analysis is 65 m/s and 1.5m. The relative velocities for airfoils have been computed using the boundary element and panel method. Boundary layer properties involving chord Reynolds number, 3.14 x106, 4.6 x106and Reynolds number based on wall shear, 7410, 6865 were assessed at 20 AOA for NACA 0012. Results have found higher values for thickness at increasing angle of attack but decayed along chord length. Comparison of wall pressure spectrum for favorable and adverse pressure gradients were done and validated with existing literature predictions.
Keywords: Airfoil, Noise, Sound Pressure Level, Trailing edge, Boundary layer
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