Measurement and Prediction of Infrasonic Wind Noise in Forests

Abstract

It is well known that infrasonic wind noise levels are lower for arrays placed in forests. In this study, the the wind noise levels, turbulence spectra, wind velocity profiles and convection velocity were measured in and above a pine forest and in a mixed deciduous forest. The wind velocity differ from those in the meteorological literature in having zero displacement length. A prediction of the measured wind noise from the measured meteorological data based on fluid dynamic theory has been developed and compared to the measured wind noise. Very good agreement between measurement and theory was achieved. Low frequency wind noise is due to the turbulence-shear interaction above the trees, while the higher frequency wind noise is due tot he turbulence-turbulence interaction within the tree canopy. Initial measurements demonstrated the necessity of measuring the convection velocity.

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Document Details

Document Type
Technical Report
Publication Date
Mar 12, 2015
Accession Number
AD1057438

Entities

People

  • Richard Raspet

Organizations

  • University of Mississippi

Tags

Communities of Interest

  • Air Platforms
  • Human Systems
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Abstracts
  • Agreements
  • Boundary Layer
  • Boundary Layer Flow
  • Convection
  • Correlation Analysis
  • Department Of Defense
  • Displacement
  • Forests
  • Frequency
  • High Resolution
  • Mathematics
  • Measurement
  • Students
  • Tree Canopy
  • Turbulence
  • Wind Velocity

Fields of Study

  • Environmental science

Readers

  • Fluid Dynamics.
  • Forest Ecology
  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers