Accession Number:

ADA142473

Title:

Effect of Turbulent Boundary Layer Flow on Measurement of Acoustic Pressure and Intensity. Revised.

Descriptive Note:

Technical memo.,

Corporate Author:

PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB

Personal Author(s):

• Lauchle,G. C.

Report Date:

1984-05-18

Pagination or Media Count:

41.0

Abstract:

Acoustic measurements performed with pressure sensors microphones and hydrophones can be subject to misinterpretation if the sensors are in contact with a turbulent boundary layer flow. This misinterpretation is a result of non-propagating pressure fields flow noise generated by the turbulent motions of the fluid. In this paper, a simple analysis is given whereby the flow noise response of a pressure sensor placed in a turbulent boundary layer flow can be estimated. If the purpose of the sensor is to measure the sound emitted from an independent source outside of the turbulent boundary layer, then a bias for the measurement can be calculated. A bias formula for intensity measurements made with two-sensors under a turbulent boundary layer is also derived under the assumption of a very low Mach number flow. Author

Descriptors:

• *TURBULENT BOUNDARY LAYER
• *ACOUSTIC MEASUREMENT
• *SOUND PRESSURE
• *BOUNDARY LAYER FLOW
• SIGNAL TO NOISE RATIO
• INTENSITY
• TURBULENT FLOW
• ESTIMATES
• FLOW FIELDS
• RESPONSE
• ACOUSTICS
• MACH NUMBER
• FLOW NOISE
• HYDROPHONES
• BIAS
• MICROPHONES
• FORMULAS(MATHEMATICS)

Subject Categories:

• Acoustics
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE