Pressure Oscillations from Cavities with Ramp

Vikramaditya, N. S.; Kurian, Job

doi:10.2514/1.43068

Cited by 53 publications

(12 citation statements)

References 15 publications

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“…Reviews of cavity noise control are given by Rowley and Williams, 4 Colonius et al, 10 and Cattafesta et al 11 Significant success has been achieved in reducing the dynamic pressure levels with passive control approaches, such as spoilers, fences, oscillating flaps, and cavities with ramps. [12][13][14][15][16] For instance, a static fence at the leading edge of the cavity was able to suppress the sound pressure level of the first mode as much as 30 dB when the height of the static fence was about equal to or greater than the boundary-layer thickness. 13 However, passive control methods are usually coupled with a penalty of drag increase and do not always work at off-design conditions.…”

Section: Introductionmentioning

confidence: 98%

Mechanism of controlling supersonic cavity oscillations using upstream mass injection

Nonomura

Fujii

2013

Physics of Fluids

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The mechanism of controlling supersonic cavity oscillations using upstream mass injection is investigated by implicit large-eddy simulations of a turbulent flow (M∞ = 2.0, ReD = 105) past a rectangular cavity with a length-to-depth ratio of 2. The mass injection is simulated by specifying a vertical velocity profile of a jet ejecting steadily through a slot placed at the upstream of the cavity leading edge. The results show that the steady upstream mass injection produces significant attenuation of the cavity oscillations, and two primary mechanisms are demonstrated to be directly responsible for the noise suppression: lifting up of the cavity shear layer, and damping of the shear-layer instability. It is found that the case of low mass flow injection investigated is more effective in stabilizing the cavity shear layer than the high mass flow injection. A transition stage might exist between two well-developed oscillating modes, but “mode-switching” is not observed.

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Section: Introductionmentioning

confidence: 98%

Mechanism of controlling supersonic cavity oscillations using upstream mass injection

Nonomura

Fujii

2013

Physics of Fluids

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“…Ünalmis 12 indicated that the cavity oscillation frequencies are accurately predicted using simple closed-box acoustic theory. In Vikramaditya's work 13 , the presence of a forward-moving acoustic wave could not be identified in the cavities with small ramp angles while the reasons for this behavior still had not been understood. In early years, the mechanism proposed by Heller and Bliss 14 supported that the aft wall mass injection and removal was responsible for the initially generation of internal cavity waves.…”

Section: Introductionmentioning

confidence: 97%

LES Study of Feedback-loop Mechanism of Supersonic Open Cavity Flows

Nonomura

Oyama

et al. 2010

40th Fluid Dynamics Conference and Exhibit

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Supersonic flow over a three-dimensional rectangular cavity with length-to-depth ratio of 2 is numerically studied by implicit large-eddy simulation to clarify the feedback-loop mechanism. A feedback-loop cycle is described and visualized with phase-averaged analysis of simulation results. Causality between the feedback acoustic wave and leading-edge shedding vortex is clearly demonstrated. Mach wave reflection at trailing edge is turned out to be the generation mechanism of feedback acoustic wave. It is convinced by investigating time-series instantaneous flowfields and auto-correlation coefficients of three simulation cases with different convective Mach number. Components of compression waves in supersonic cavity flows are summarized and their features are discussed. Proper orthogonal Decomposition (POD) in frequency domain is firstly employed to analyze wave propagations inside cavity. Results statistically show the propagation traces of notable compression waves inside cavity which are affected by high-speed recirculation flows.

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“…For passive control, the common method is to mount spoilers at the upstream of the cavity front wall or replace the cavity front/rear wall by ramps [17][18][19] . The other method such as using a sub-cavity on the front wall of the cavity covered by a flat plate [20][21] has been proven to be effective.…”

Section: Introductionmentioning

confidence: 99%

Mode transition and oscillation suppression in supersonic cavity flow

Zhang

Wan

Sun

2016

Appl. Math. Mech.-Engl. Ed.

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Supersonic flows past two-dimensional cavities with/without control are investigated by the direct numerical simulation (DNS). For an uncontrolled cavity, as the thickness of the boundary layer declines, transition of the dominant mode from the steady mode to the Rossiter II mode and then to the Rossiter III mode is observed due to the change of vortex-corner interactions. Meanwhile, a low frequency mode appears. However, the wake mode observed in a subsonic cavity flow is absent in the current simulation. The oscillation frequencies obtained from a global dynamic mode decomposition (DMD) approach are consistent with the local power spectral density (PSD) analysis. The dominant mode transition is clearly shown by the dynamic modes obtained from the DMD. A passive control technique of substituting the cavity trailing edge with a quarter-circle is studied. As the effective cavity length increases, the dominant mode transition from the Rossiter II mode to the Rossiter III mode occurs. With the control, the pressure oscillations are reduced significantly. The interaction of the shear layer and the recirculation zone is greatly weakened, combined with weaker shear layer instability, responsible for the suppression of pressure oscillations. Moreover, active control using steady subsonic mass injection upstream of a cavity leading edge can stabilize the flow.

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Pressure Oscillations from Cavities with Ramp

Cited by 53 publications

References 15 publications

Mechanism of controlling supersonic cavity oscillations using upstream mass injection

Mechanism of controlling supersonic cavity oscillations using upstream mass injection

LES Study of Feedback-loop Mechanism of Supersonic Open Cavity Flows

Mode transition and oscillation suppression in supersonic cavity flow

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