Improved Technique for Evaluation of Wall Pressure Fluctuations from Turbulent Boundary Layer

Abstract

The wall pressure fluctuations produced by a turbulent boundary layer (TBL) are the main excitation of structural vibrations and cabin noise in aircraft. To precisely estimate the structural vibration excited by a TBL, an improved technique is proposed and developed for the prediction of wall pressure fluctuations induced by a high-speed flow. First, an integrated expression is given to describe wall pressure fluctuations in different situations, and a conventional phase array technique is employed to identify the wave numbers of the wall pressure fluctuations and noise. Then, the pressure fluctuations are separated from the noise by a modified subsection approaching method. To improve the resolution of the low-frequency noise, an accelerated focusing method is developed and used in this paper. A variable spacing array design is proposed to improve the calculation accuracy of the broadband pressure fluctuation separation. In addition, a sensitivity analysis is carried out to fix the error range of the noise wave numbers in which the pressure fluctuation and noise calculation converges to the actual value. Finally, a wind-tunnel test is performed to validate the proposed method in this work.