Low-Frequency Shock Motion in Transonic Convex-Corner Flows

Chung, Kung Ming; Lee, Kuan Huang; Chang, Po Hsiung

doi:10.2514/1.j055430

Cited by 4 publications

(4 citation statements)

References 19 publications

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“…), is used to characterize a compressible convex corner flow (peak Mach number, M p , peak pressure fluctuations, and shock oscillation) [3]. If β > 13, SIBLS occurs and induces low-frequency, high-amplitude shock oscillations [4].…”

Section: Introductionmentioning

confidence: 99%

“…There is a decrease as M p increases. Variation in f s is related to the length of a separation bubble [4]. The presence of VGs reduces the shock oscillation where f s = 929 Hz-126 Hz.…”

mentioning

confidence: 99%

“…For SIBLS, the unsteady shock motion is related to successive contractions and expansions of a separation bubble. The normalized separation length, L * (L/δ), can be used as a length scale to characterize shock unsteadiness [4]. The variation of L * with M p is shown in Figure 12.…”

mentioning

confidence: 99%

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Separation Control for a Transonic Convex Corner Flow Using Ramp-Type Vortex Generators

Chung

Исаев

2022

International Journal of Aerospace Engineering

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A flap can be used to control wing camber and as a high-lift device. A convex corner is a simplified model of the upper surface of a flap. At transonic speeds, shock-induced boundary layer separation (SIBLS) occurs at greater freestream Mach numbers and deflection angles. This results in energy losses and a reduction in aerodynamic performance. This study installs ramp-type vortex generators (VGs) upstream of a convex corner, and the effect of the height of the VG on SIBLS is determined. As the height of the VG increases, the magnitude of the mean surface pressure upstream of the corner increases and downstream expansion decreases, which results in a reduction in lift. A reduction in peak surface pressure fluctuations, the separation length, and the frequency of shock oscillation is also determined. For flow control and lift enhancement, micro-VGs are more effective.

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Section: Introductionmentioning

confidence: 99%

“…There is a decrease as M p increases. Variation in f s is related to the length of a separation bubble [4]. The presence of VGs reduces the shock oscillation where f s = 929 Hz-126 Hz.…”

mentioning

confidence: 99%

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Separation Control for a Transonic Convex Corner Flow Using Ramp-Type Vortex Generators

Chung

Исаев

2022

International Journal of Aerospace Engineering

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“…A similarity parameter β (= M 2 η/ 1 − M 2 ) was proposed for compressible flow around a convex corner, which involves transition from subsonic to transonic flow (β ≈ 8), shock-induced boundarylayer separation (SIBLS) (β > 13) and peak pressure fluctuations [4]. These peak pressure fluctuations are associated with low-frequency, large-scale shock oscillation in the range of several hundred hertz to several kilohertz [5].…”

Section: Introductionmentioning

confidence: 99%

Micro-Vortex Generators on Transonic Convex-Corner Flow

Chung

Chang

2021

Aerospace

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A convex corner models the upper surface of a deflected flap and shock-induced boundary layer separation occurs at transonic speeds. This study uses micro-vortex generators (MVGs) for flow control. An array of MVGs (counter-rotating vane type, ramp type and co-rotating vane type) with a height of 20% of the thickness of the incoming boundary layer is installed upstream of a convex corner. The surface pressure distributions are similar regardless of the presence of MVGs. They show mild upstream expansion, a strong favorable pressure gradient near the corner’s apex and downstream compression. A corrugated surface oil flow pattern is observed in the presence of MVGs and there is an onset of compression moving downstream. The counter-rotating vane type MVGs produce a greater reduction in peak pressure fluctuations and the ramp type decreases the separation length. The presence of MVGs stabilizes the shock and shock oscillation is damped.

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An experimental study on transonic swept convex-corner flows

Chung

2019

Aerospace Science and Technology

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Low-Frequency Shock Motion in Transonic Convex-Corner Flows

Cited by 4 publications

References 19 publications

Separation Control for a Transonic Convex Corner Flow Using Ramp-Type Vortex Generators

Separation Control for a Transonic Convex Corner Flow Using Ramp-Type Vortex Generators

Micro-Vortex Generators on Transonic Convex-Corner Flow

An experimental study on transonic swept convex-corner flows

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