Exploitation of hybrid anechoic wind tunnels for aeroacoustic and aerodynamic measurements

摘要

The last 10 years have seen the establishment of the hybrid anechoic wind tunnel as a significant tool for experimental aer-oacoustics research. The hybrid anechoic wind tunnel features a test section which is effectively closed in the aerodynamic sense but open in the acoustic sense, this unique behavior being achieved by stretching fabric of high strength-to-weight ratio (such as Kevlar) over windows in the test section walls which open to anechoic chambers. The hybrid anechoic arrangement offers a number of advantages over the traditional open-jet test section, including low interference corrections that allow for testing of large models at higher Reynolds numbers-advantages well suited to aircraft noise source research. In this article, we review recent applications of hybrid anechoic tunnels for aircraft noise source studies. We discuss the established practice for acoustic and aerodynamic correction of measurements performed in these facilities, and assess some of the latest findings in aerodynamic behavior of hybrid anechoic tests sections.