A NOTE ON MEASUREMENT OF SOUND INTENSITY WITH WINDSCREENED PROBES

The influence of windscreens of porous foam on the performance of soun d intensity probes is examined. It is shown that windscreens can lead to significant underestimation of the sound power of a source at low f requencies if the measurement is carried out in the reactive near fiel d of the source, but have no appreciable undesirable effect on the res ult if the measurement surface is further away from the source. In add ition, some empirical observations on measurement of sound intensity i n the presence of airflow are presented