Sound control in windy weather
Author
Buchholdt, Jonas Flensborg Riis
Term
4. term
Education
Publication year
2019
Submitted on
2019-06-05
Pages
238
Abstract
Dette speciale undersøger, hvordan inhomogene atmosfæriske forhold – især vind, der varierer med sted – påvirker lydudbredelsen fra et line source array (en række højttalere, der virker som én samlet kilde). Analysen viser, at inhomogen vind refrakterer (bøjer) lyden, så lydtrykniveauet (SPL, den målte lydstyrke i decibel) bliver ujævnt i dækningsområdet. Specialet foreslår en løsning, der mindsker forskellene i SPL-dækning ved både sidevind (crosswind) og parallel vind (vind i samme retning som lydens udbredelse). I tilfældet med parallel vind analyseres kun opadgående refraktion. Målinger viser, at forskellen mellem opadgående og nedadgående retning kan reduceres fra over 17 dB til under 3 dB. Derudover kan SPL i skyggezonen øges under parallel vind ved at vippe line source arrayet fremad.
This thesis investigates how inhomogeneous atmospheric conditions—especially wind that varies with position—affect how sound travels from a line source array (a row of loudspeakers acting as a single source). The analysis shows that inhomogeneous wind refracts (bends) the sound, leading to uneven Sound Pressure Level (SPL, the measured loudness in decibels) coverage across the area. The thesis proposes a solution to reduce these SPL differences for both crosswind (wind from the side) and parallel wind (wind along the direction of sound propagation). In the parallel wind case, only upward refraction is analyzed. Measurements show that the difference between the upward and downward directions can be reduced from over 17 dB to less than 3 dB. In addition, under parallel wind, forward tilting of the line source array raises the SPL in the shadow zone (areas that would otherwise receive little sound).
[This abstract was generated with the help of AI]
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