作者: Xiaopeng Li , E. Fan , Wei Yao , Xuejun Fan
DOI: 10.1016/J.AST.2017.01.005
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摘要: Abstract A highly underexpanded jet with a nozzle pressure ratio of 5.60 is excited simultaneously by the inherent characteristic frequencies in steady 14.569 kHz, 37.086 and 45.695 kHz as well other two reference 1.0 40.0 kHz. The flow jets revealed comparing to using large eddy simulation technique. For low-frequency excitation ( f e = kHz ), acoustic fields forcing are similar jet. However, when high frequencies, source moves exit, potential core together near-field shocks oscillate periodically at frequency. increases mixing area since y / D 24 from which contrary effect that enhances region but decreases 18 . peak frequency generally becomes identical once being excited, except jets. High-order harmonics dominant observed spectrum mode turns into axisymmetric original helical one accordingly. In particular, provides fewest shock cells largest amplitude oscillation, most spectrum, within 8 ≤ 12