ASA 126th Meeting Denver 1993 October 4-8

5aPA13. Low-frequency wind noise for a microphone inside a spherical foam windscreen.

Scott Morgan

Dept. of Phys., Southeastern Louisiana Univ., 878 SLU, Hammond, LA 70402

Richard Raspet

Univ. of Mississippi, University, MS 38677

Windscreens are commonly used to reduce wind noise in outdoor measurements by shielding the microphone from the incoming flow. In this paper a theoretical model for wind noise reduction of a spherical foam windscreen and experimental evidence supporting this model are presented. Results show that wind noise reduction is approximately independent of windscreen diameter for turbulence scale sizes that are much larger than the windscreen and that wind noise reduction scales well with the screen number (defined as the ratio of the windscreen diameter to the scale size of the turbulent eddies) for screen number values less than one. Calculations using average windscreen surface pressure measurements yield wind noise reductions that are of the same order of magnitude as those measured.