Frequencies of Transverse and Longitudinal Oscillations in Supersonic Cavity Flows

Handa, Taro; Tanigawa, Kazuya; Kihara, Yusuke; Miyachi, Hiroaki; Kakuno, Hatsuki

doi:10.1155/2015/751029

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…The presence of a cavity changes the mean and fluctuating pressure distributions inside and near a cavity [1,2]. For compressible flow in a rectangular cavity ( = 0.2-0.95), the mean and fluctuation pressure distributions normal to the direction of the flow depend principally on the length-todepth ratio, / [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Yaw Angle on a Compressible Rectangular Cavity Flow

Lee

Chung

Chang

2017

International Journal of Aerospace Engineering

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Experiments are performed to determine the characteristics of a compressible flow over yawed rectangular cavities for Mach numbers of 0.64, 0.70, and 0.83. The cavity's length-to-depth ratio varies from 4.43 to 21.50 and the length-to-width ratio is unity. The yaw angle is 0 ∘ -45 ∘ . The upstream compression and downstream expansion near the front and rear corners of a cavity decrease when the value of the yaw angle increases. The amplitude of the fluctuating pressure is a maximum for an open cavity with a yaw angle of 15∘ . An increase in the yaw angle results in a reduction in the pressure fluctuations for both open and transitional cavities. In the span-wise direction, variations in the mean and fluctuating pressure are less significant than those in the chord-wise direction. The oscillating frequency of resonance varies slightly with the yaw angle, but the amplitudes for the power spectral density are significantly reduced when the yaw angle is larger than 30 ∘ . For lower Mach numbers, the lower mode plays an important role in self-sustained oscillations for an open cavity when there is an increase in the yaw angle.

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Section: Introductionmentioning

confidence: 99%

The Effect of Yaw Angle on a Compressible Rectangular Cavity Flow

Lee

Chung

Chang

2017

International Journal of Aerospace Engineering

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“…Research on the landing gear bay noise can date back to the 1970s [5,6], and the cavity oscillation has been identified as the main characteristic of the noise emission. To predict frequencies or the Strouhal number of the oscillation, Rossiter [7] proposed a semiempirical equation based on the experimental data, which has been widely used in the subsequent cavity noise studies [8][9][10][11]. As for the noise reduction, a few ideas have been proposed either for the landing gear or for the bay, such as the fairings [12,13], plasma [14,15], mesh [16,17], air curtain [18][19][20][21], and upstream mass flow injection [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

An Experimental Characterization on the Acoustic Performance of Forward/Rearward Retraction of a Nose Landing Gear

Liang

Zhao

Chen

et al. 2019

International Journal of Aerospace Engineering

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The modern undercarriage system of a large aircraft normally requires the landing gear to be retractable. The nose landing gear, installed in the front of the fuselage, is retracted either forward or rearward. In the forward/rearward retraction system, the landing gear is normally installed to the trailing/leading side of the bay. When the incoming flow passes the landing gear as well as the bay, the installation that corresponds to the forward/rearward retraction system has a significant impact on the coupling flow and the associated noise of the landing gear and the bay. In this paper, acoustic performance of the forward/rearward retraction of the nose landing gear was discussed based on experiment. The landing gear bay was simplified as a rectangular cavity, and tests were conducted in an aeroacoustics wind tunnel. The cavity oscillation was first analyzed with different incoming speeds. Then, the landing gear model was installed close to the trailing and the leading side of the cavity, respectively. It was observed that installation close to the leading side can help disturb the shear layer so as to suppress the oscillation, while the trailing one can make the landing gear itself produce lower noise. Accordingly, conclusions on the acoustic performance of the forward/rearward retraction of the nose landing gear are made.

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“…When the cavity is deep, it is known as an open cavity flow, and the shear layer bridges the cavity. The normal mode or the feedback loop is responsible for strong self-sustained oscillations [4][5][6][7][8][9], which give rise to structural loading problems and acoustic noise. In the case of shallow (or closed) cavity flow, two distinct separation regions exist downstream of the front face and upstream of the rear face.…”

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confidence: 99%