Last edited by Meztilkis
Monday, August 10, 2020 | History

3 edition of Long range downwind propagation of low-frequency sound found in the catalog.

Long range downwind propagation of low-frequency sound

Long range downwind propagation of low-frequency sound

  • 162 Want to read
  • 36 Currently reading

Published by National Aeronautics and Space Administration, Langley Research Center, For sale by the National Technical Information Service in Hampton, Va, [Springfield, Va .
Written in English

    Subjects:
  • Wind turbines,
  • Noise -- Measurement

  • Edition Notes

    StatementWilliam L. Willshire, Jr
    SeriesNASA technical memorandum -- 86409
    ContributionsLangley Research Center
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL14926844M

    Site Distance from Blast Overpressure Ppeak, Pa Peak Sound Level Lpeak, dB Exposure Level CSEL, dBC Maximum Level LCmax, dBC 1 m - > * - - 2 m - > * > * > * 3 km - - 4 2 km 89 - - 5 km 50 - - 6 km 40 7 45 km 11 8 90 km 98^ - 90^ Table 1: Noise Measurement Results for the Monitoring Sites from the June P&EE Blast.   In this work, we show that large-scale processes of the long-range propagation and scattering of infrasound signals in stratospheric and thermospheric waveguides are to some extent similar to the smaller scale processes of waveguide propagation and scattering of acoustic signals in stably stratified ABL. Moreover, we note a resemblance between the zeroth order tropospheric mode and the .

    Experiments on Sound Propagation over Sloped Bottoms.- The Effect of Unconsolidated Sediment Rigidity on Low Frequency Acoustic Propagation.- A Propagation Anomaly Observed in the Barents Sea.- Long Range Low Frequency Propagation Measurements in Deep . [11] Table S1 also indicates the maximum of the effective sound speed ratio (V eff‐ratio).This dimensionless parameter is a proxy for the combined effects of refraction due to sound speed gradients and along‐path wind advection on infrasound propagation [e.g., Le Pichon et al., ].It is defined as the ratio between the maximum of the along‐path wind plus the adiabatic sound speed at.

    The SOFAR channel (short for Sound Fixing and Ranging channel), or deep sound channel (DSC), is a horizontal layer of water in the ocean at which depth the speed of sound is at its minimum. The SOFAR channel acts as a waveguide for sound, and low frequency sound waves within the channel may travel thousands of miles before dissipating. This phenomenon is an important factor in submarine warfare. Our long-term scientific goal is to understand the basic physics of low-frequency long-range sound propagation in the ocean, and the effects of environmental variability on signal stability and coherence. We seek to understand the fundamental limits to signal processing imposed by ocean variability to enable.


Share this book
You might also like
Fourth five year plan, 1969-74; questions and answers.

Fourth five year plan, 1969-74; questions and answers.

Gazatteer and administrative maps of Herefordshire.

Gazatteer and administrative maps of Herefordshire.

Development and utilization of the model LSC201 lightning counter

Development and utilization of the model LSC201 lightning counter

Private enterprise in the developing countries

Private enterprise in the developing countries

State laws affecting working women.

State laws affecting working women.

costs of protectionism to developing countries

costs of protectionism to developing countries

Cross-index to the geological illustrations of Canada v.4.

Cross-index to the geological illustrations of Canada v.4.

The Charm School / The Horsemans Daughter / The Hostage

The Charm School / The Horsemans Daughter / The Hostage

22nd annual Offshore Technology Conference

22nd annual Offshore Technology Conference

Of morning stars

Of morning stars

Elements of an energy-efficient house

Elements of an energy-efficient house

Captain Abduls pirate school.

Captain Abduls pirate school.

Afloat at last

Afloat at last

Long range downwind propagation of low-frequency sound Download PDF EPUB FB2

NASA Technid Memorandum 9 Long Range Downwind Propagation Of Low-Frequency Sound (bASA-TU-E64C 5) LCPG EAblGk ECEIUIBC NE IiiOPA6AIICI OF ICh-EEOCUBICL SCUSL (USA) 21 p BC AaZ/BE 1C4 CSCL 20~ Uncla s G3/71 L1C55 William L.

Willshire, Jr. April Natlonal Aeronaut~cs and. Long range downwind propagation of low-frequency sound book propagation of low-frequency noise outdoors was studied using as the source a large (m diameter) 4-megawatt horizontal axis wind turbine. Acoustic measurements were made with low-frequency microphone systems placed on the ground at five downwind sites ranging from m to 10, m ( mile) away from the wind turbine.

Long range downwind propagation of low-frequency sound The propagation of low-frequency noise outdoors was studied using as the source a large (m diameter) 4-megawatt horizontal axis wind turbine.

Acoustic measurements were made with low-frequency microphone systems placed on the ground at five downwind sites ranging from m to 10, m ( mile). Get this from a library. Long range downwind propagation of low-frequency sound. [William L Willshire; Langley Research Center.]. NASA Long Range Down Wind Propagation of Low Frequency Sound NASA Technical Memorandum, William L.

Willshire, The propagation of low-frequency noise outdoors was studied using as the source a large ( diameter) 4-megawatt horizontal axis wind turbine.

Acoustic measurements were made with low-frequency microphone systems placed on the ground at five downwind. “ Long-range sound propagation over the sea with application to wind turbine noise,” Swedish Energy Agency, Reportp.

; Johansson, The propagation of low-frequency noise outdoors was studied using as the source a large (m diameter) 4-megawatt horizontal axis wind turbine. Acoustic measurements were made with low-frequency microphone systems placed on the ground at five downwind sites ranging from m to 10, m ( mile) away from the wind turbine.

The wind turbine fundamental was 1 Hz and the wind. Sound Propagation through the Stochastic Ocean provides a comprehensive treatment of developments in the field of statistical ocean acoustics over the last 35 years.

This will be of fundamental interest to oceanographers, marine biologists, geophysicists, engineers, applied mathematicians, and physicists. “ Testing meteorological classifications for the prediction of long-term average sound levels,” Appl. Acoust. “ Long range downwind propagation of low-frequency sound,” NASA TM (April).

Google Scholar; Willshire, W., and Zorumski W. Title. International Workshop on Low-Frequency Propagation and Noise, Woods Hole, Massachusetts, October, / By.

International Workshop on Low-Frequency Propagation and Noise Woods Hole, Mass.) appropriate to predict the propagation of low-frequency.

in the downwind direction, sound levels do not. test cases show that long range sound propagation and diffraction by obstacles in. Applied Acoustics 33 () The Fast Field Program (FFP). A Second Tutorial: Application to Long Range Sound Propagation in the Atmosphere M. Westa, R. Sackb & F. Walkdenb ° Department of Applied Acoustics, b Department of Mathematics and Computer Science, University of Salford, Salford, Greater Manchester M5 4WT, UK (Received 18 June ; revised.

Seafloor investigation has long been a feature of not only seismology but also of acoustics. Indeed it was acoustics that produced depth sounders, giving us the first capability of producing both global and local maps of the seafloor. Subsequently, better instrumentation and techniques led to a.

The feasibility of acoustical scale modeling techniques for modeling wind effects on long range, low frequency outdoor sound propagation was evaluated.

Upwind and downwind propagation was studied in 1/ scale for flat ground and simple hills with both rigid and finite ground impedance over a full scale frequency range from 20 to Hz. Abstract: This paper provides an overview of the experimental goals and methods of the Long-range Ocean Acoustic Propagation EXperiment (LOAPEX), which took place in the northeast Pacific Ocean between Septem and Octo This experiment was designed to address a number of unresolved issues in long-range, deep-water acoustic propagation including.

In the case of Figure 22 this results in a low-frequency and low-angle reflection loss of about 1 dB. For long ranges and many reflections this adds up to a significant total propagation loss. With no shear conversion the reflection loss is considerably reduced and the sound propagates easier to long.

Long Range Sound Propagation (LRSP) The International Symposia on Long Range Sound Propagation are held every two years alternately between the US and Europe. The goals of the symposia are to exchange information on current research in sound propagation in the atmosphere ranging from infrasound to low frequency audible sound.

In the Sea of Japan at the research of long- range propagation of explosive signals in conditions of the underwater sound channel (USC) the time structure of a sound field was analyzed. Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another, or into various parts of the atmosphere.

As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. Understanding the effects of varying conditions on radio.

Journal of Sound and Vibration () 98(l), ON THE LONG RANGE PROPAGATION OF SOUND OVER IRREGULAR TERRAIN M. HOWE i Bolt Beranek and Newman Inc, 50 Moulton Street, Cambridge, MassachusettsUS.A.

(Received 14 Januaryand in revised form 15 March The theory of sound propagation over randomly irregular, nominally. Because of property 1, only low-frequency sounds are useful for studying large-scale processes over long distances, such as the structure of the ocean over scales of hundreds to thousands of kilometers.

For example, sound has been used to study circulation patterns in the ocean using tomographic techniques analogous to the CAT [computerized axial tomography] scan technology used in medicine.The results show a pronounced increase in low-frequency attentuation reaching a maximum in the frequency range of to Hz.

The results also indicate that current differences for downwind sound propagation between those measured feet and.Remember, sound is a pressure wave vibration of molecules. Whenever you give molecules a "push" you're going to lose some energy to heat. Because of this, sound is lost to heating of the medium it is propagating through.

The attenuation of sound waves is frequency dependent in most materials.