Introduction Fan noise in low-speed equipment has been identified as a primary source of overall noise in many heat-exchange applications. When used with engine or motor-driven equipment that has been designed for good noise control, attention must be directed to reduction of the fan-generated noise in order to reduce annoyance levels or to bring the equipment within maximum sound level specifications For typical heat-exchange applications, a low-speed, lowpressure axial fan usually meets the design requirements most effectively in terms of performance capability and cost of equipment. Use of these fans in conjunction with a heat exchanger results in dominant components of generated noise associated with the ingestion by the fan of small-scale, highintensity turbulence. The focus of this work is to examine blade sweep as a means for alleviating the dominant source of noise, while providing a method of estimating the influence on fan performance. As described b
