Modeling Wind Tunnel Effects on the Radiation Characteristics of Acoustic Sources
The important features of the acoustic field of a propeller operating within a wind tunnel are modeled. The wind tunnel is taken to be of circular cross section, with the flowfield assumed to be uniform. A finite element formulation based on a Gutin type of propeller theory is used to represent the acoustic source both in the wind tunnel and in a free field for comparison purposes. The information sought is the accuracy with which propeller acoustic directivity on the wind tunnel wall matches directivity measured on a reflecting plane placed near the propeller in the free field. An important analytical result shows that it is not possible to obtain an accurate directivity in the tunnel environment unless the modal cutoff ratio for the source exceeds unity for at least the lowest-order mode generated. This result is verified numerically.
W. Eversman and K. J. Baumeister, "Modeling Wind Tunnel Effects on the Radiation Characteristics of Acoustic Sources," Journal of Aircraft, American Institute of Aeronautics and Astronautics (AIAA), Jan 1986.
The definitive version is available at http://dx.doi.org/10.2514/3.45329
Mechanical and Aerospace Engineering
Article - Journal
© 1986 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.