Sensor Flow-Induced Self Noise Reduction

Abstract

Boundary-layer transition and the fully-developed turbulent boundary are important contributors to sensor flow-induced self noise. The wall pressure fluctuations caused by these shear flows can be attenuated by localized fluid injection. Presented here is a vehicle forebody design concept that permits water to be injected into the transition region and adjacent turbulent boundary layer at prescribed volumetric flow rates. The injection flow rate may be tailored by a variable thickness porous shell made from powdered metal, or from a variable distribution of micro-hole perforations. Pressure to cause the injection is provided by the vehicle dynamic head. Up to 10 dB reduction of flow-induced self noise of sensors mounted in this forebody is demonstrated in small water tunnel tests.

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Document Details

Document Type
Technical Report
Publication Date
Oct 16, 2002
Accession Number
ADA408916

Entities

People

  • G. C. Lauchle
  • Sehyun Park

Organizations

  • Pennsylvania State University

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Boundary Layer
  • Boundary Layer Flow
  • Composite Materials
  • Fabrication
  • Flow Noise
  • Fluid Dynamics
  • Free Stream
  • Materials
  • Military Research
  • Noise Reduction
  • Pressure Distribution
  • Pressure Transducers
  • Self Noise
  • Sonar Transducers
  • Transducers
  • Turbulent Boundary Layer
  • Turbulent Flow

Fields of Study

  • Physics

Readers

  • Acoustics.
  • Fluid Dynamics.