Abstract

Open up cavities at transonic speeds can result in acoustic resonant flow behavior with fluctuating pressure level levels of sufficient intensity to cause significant damage to internal stores and surrounding structures. Extensive inquiry in this field has produced numerous cavity catamenia control techniques, the more than effective of which may require costly feedback control systems or entail other drawbacks such equally drag penalties or rapid functioning degradation at off-design condition. The current study focuses on the utilise of uncomplicated geometric modifications of a rectangular planform crenel with the aim of attenuating the aeroacoustic signature. Experiments were performed in an intermittent suck-downward transonic wind tunnel by using a typical open flow rectangular planform crenel, which was modularly designed such that the leading and trailing edge geometries could be modified past using a family unit of inserts. The electric current work focused on a variety of recessed leading border stride arrangements. Configurations were tested at transonic Mach numbers spanning the range Mach 0.seven–0.9, and unsteady pressure measurements were recorded at diverse stations inside the crenel in order to obtain acoustic spectra. The virtually constructive configuration at Mach 0.9 was the leading edge footstep employing a step tiptop to pace length ratio of 0.4. This configuration achieved a tonal attenuation of up to 18.half-dozen dB and an overall sound pressure level (OASPL) reduction of approximately 7.5 dB ⁠. This is a pregnant level of racket suppression in comparing with other passive control methods. In addition, it offers the additional benefits of beingness a simple geometric feature, which does not rely on placing flow effectors into the high-speed grazing flow.

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 by American Society of Mechanical Engineers

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