Experimental investigation of typical surface treatment effect on velocity fluctuations in turbulent flow around an airfoil

Abstract

Noise reduction of different airfoils is important because these sections are used in wind turbines, propellers, and aircraft wings. Several methods are used for passive noise reduction of sections. One of these methods is the use of surface treatment. In this research, the effect of the typical surface treatment element (finlets) on the vortex structure at different frequencies in the turbulent flow created on the NACA2412 section is investigated. For this purpose, one-dimensional hot wire probe is used. The used surface treatment in this research has a special geometry and the distance between two consecutive finlets is 6 mm (S = 6 mm). This study shows that this surface treatment element can be used for noise reduction in high frequencies. Another result of this research is the suggestion of the most suitable position to install this special surface treatment element to reduce vortex energy in all frequency ranges. This installation location is determined based on a dimensionless parameter (Xaft/h).