Reduced-size windscreens for infrasound

Abstract

The long wavelengths of infrasound necessitate large, often complex, wind noise reduction apparatus, e.g., porous hose, pipe arrays, or wind fences. For the infrasonic sources of military interest that fall between approximately 2 and 20 Hz, 6-m radius porous hose rosettes are often sufficient windscreens. However, the number of hoses required for a typical 4-element infrasound array (16–24) reduces its portability. Based upon recent research demonstrating that porous fabric domes could outperform porous hoses in the 2–20 Hz region and a need for more compact windscreens, 1.2-m diameter domes covered in three types of porous fabric and one folding perforated aluminum dome were investigated for their suitability as alternatives to porous hose. Evaluations of wind noise reduction, transfer functions, and environmental durability will be presented for these alternative windscreens.