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Microphone Measurements In and Out of Airstream

  • Paul T. Soderman
  • Christopher S. Allen
Chapter
Part of the Experimental Fluid Mechanics book series (FLUID)

Abstract

The wind tunnel has become an important research facility for the study of aircraft and automobile noise. In this chapter, the acoustic characteristics of wind tunnels are discussed along with methods for conducting research in such an environment. Microphone measurements require low background noise and minimal reflections for accurate results. Typical sources of wind tunnel background noise are described including noise from the wind tunnel components, apparatus support struts, and microphones installed in the flow. In most cases, proper design of wind tunnel components and test apparatus are critical to successful aeroacoustic measurements. And, it is often necessary to add silencers and acoustic treatment to the facility. Criteria for proper simulation of aeroacoustic phenomena are discussed along with necessary data manipulations to correct for propagation effects, scaling to the correct source size, and extrapolating to the desired flight or drive-by situation. Finally, current methods are discussed for identification and analysis of noise sources using advanced signal analysis techniques.

Keywords

Wind Tunnel Shear Layer Sound Pressure Level Acoustic Pressure Sound Absorption 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • Paul T. Soderman
    • 1
  • Christopher S. Allen
    • 2
  1. 1.NASA Ames Research CenterMoffett FieldUSA
  2. 2.NASA Johnson Space CenterHoustonUSA

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