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A comprehensive finite element methodology is developed to predict the compressible flow performance of a non-symmetric 7-blade axial flow fan, and to quantify the source strength and sound pressure levels at any location in the system. The acoustic and flow performances of the fan are predicted simultaneously using a computational aero-acoustic technique combining transient flow analysis and noise propagation. The calculated sound power levels compare favorably with the measured sound power data per AMCA 300-96 code.

Sound quality has become an important factor in determining customer perception of overall vehicle quality and value in the automotive industry [1]. Recently, in the agricultural and construction machinery industry, the concept of sound quality has gained merit as a possible vehicle for delivering quieter products to customers [2]. This paper studies the application of sound quality methodology for agricultural and construction machinery. Accordingly, the state of agricultural and construction machinery sound quality in the market place is evaluated and sound quality metrics that correlate well with the customers' subjective preferences are identified. The relevance of the chosen sound quality metrics is established by combining the results of the listening-jury evaluation and the requirements for product noise control as driven by competition and regulations.