Accession Number:

ADA270532

Title:

Approximate Evaluation of the Spectral Density Integral for a Large Planar Array of Rectangular Sensors Excited by Turbulent Flow

Descriptive Note:

Corporate Author:

NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT

Report Date:

1993-06-01

Pagination or Media Count:

9.0

Abstract:

An approximate numerical procedure has been developed for rapidly evaluating the spectral density integral that predicts the output of a planar array of many sensors excited by turbulent boundary layer pressure fluctuations. This procedure is particularly useful in cases where the transfer function factor of the integrand is not a simple function of the wave numbers in the flow and transverse directions. The procedure exploits the facts that the entire integrand is a seperable function of these two wave numbers and, when the number of sensors is large, the array function factor of the integrand is a rapidly varying function of wave number, characterized by many similar shaped lobes. In addition, a model for multilayered media is employed to provide the transfer function for boundary conditions that closely correspond to reality. Results generated by this procedure were compared to those from an exact evaluation of the integral which is possible if the transfer function is taken to be constant there was agreement to within 0.2dB or better over a broad frequency interval. Some results for a realistic transfer the sensors embedded at an arbitrary position within the layer. Sonar arrays, Turbulent flow, Spectral density, Wavenumber spectrum, Transfer function

Subject Categories:

  • Acoustic Detection and Detectors
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE