± 10°and ± 15°) or under conditions of high turbulence intensity (e.g. However, at higher angles of attack (e.g. $ 4% in the experiment) flow, by increasing the size of the crack, tonal noise appears at trailing-edge thickness-based Strouhal number, St h, approx-imatively equal to 0.1. As expected, at small angles of attack, with clean or low turbulence intensities (e.g. The spectral differences of sound pressure level between the damaged cases and the baseline (without any damage) are compared. Far-field noise scattered from the airfoil is measured by means of a microphone array. Experiments are conducted at different mean flow velocities, inflow turbulence intensities and angles of attack. A NACA 0018 airfoil with chord of 200 mm with different trailing edge crack sizes, 0.2, 0.5, 1.0 and 2.0 mm, is investigated. In this work, a new non-contact damage-detection approach is experimentally investigated based on the measurement of airfoil aerodynamic noise. In recent years, with the development of the wind power industry and the increase in the number of wind turbines, the condition monitoring of blades and the detection of damage are increasingly important.
0 Comments
Leave a Reply. |