Effects of Sidewalls and Leading-Edge Blowing on Flows over Long Rectangular Cavities

Sun, Yiyang; Liu, Qiong; Cattafesta, Louis N.; Ukeiley, Lawrence; Taira, Kunihiko

doi:10.2514/1.j057413

Cited by 36 publications

(32 citation statements)

References 50 publications

(78 reference statements)

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“…Structured meshes with 7 and 14 million grid points are used for cases with Re D = 502 and 10 4 , respectively. The grid resolutions have been found to be sufficient to resolve the flow structures as discussed in our previous studies [23,34].…”

Section: B Compressible Laminar and Turbulent Open-cavity Flowsmentioning

confidence: 78%

“…The findings provide rich information in terms of spatial distribution, growth/decay rate and temporal frequencies of disturbances that develop under the given base flows. The fruitful results from stability analysis have also served as guidelines in many steady control efforts aimed at suppressing cavity flow oscillations [22,23]. The resolvent analysis discussed in the present work is aimed to provide insights for unsteady control designs in turbulent flow to potentially improve the control performance.…”

Section: Introductionmentioning

confidence: 98%

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Resolvent Analysis of Compressible Laminar and Turbulent Cavity Flows

et al. 2020

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The present work demonstrates the use of resolvent analysis to obtain physical insights for open-cavity flows. Resolvent analysis identifies the flow response to harmonic forcing, given a steady base state, in terms of the response and forcing modes and the amplification gain. The response and forcing modes reveal the spatial structures associated with this amplification process. In this study, we perform resolvent analysis on both laminar and turbulent flows over a rectangular cavity with length-to-depth ratio of L/D = 6 at a free stream Mach number of M ∞ = 0.6 in a spanwise periodic setting. Based on the dominant instability of the base state, a discount parameter is introduced to resolvent analysis to examine the harmonic characteristics over a finite-time window. We first uncover the underlying flow physics and interpret findings from laminar flow at Re D = 502. These findings from laminar flow are extended to a more practical cavity flow example at a much higher Reynolds number of Re D = 10 4 . The features of response and forcing modes from the laminar and turbulent cavity flows are similar to the spatial structures from the laminar analysis. We further find that the large amplification of energy in flow response is associated with high frequency for turbulent flow, while the flow is

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Section: B Compressible Laminar and Turbulent Open-cavity Flowsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 98%

Resolvent Analysis of Compressible Laminar and Turbulent Cavity Flows

et al. 2020

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“…In the past few decades, a number of methods and devices have been investigated with the aim to reduce the aerodynamic noise, which can be classified into active and passive techniques [9]. Active control techniques need some energy input or relevant auxiliary equipment to manipulate the flow around the objects, such as wall-normal suction or blowing [10][11][12][13] and plasma actuator [14]. On the other hand, passive techniques can control noise emission by making small geometry changes or adding other materials to the surface of the objects, such as vortex generator [15].…”

Section: Introductionmentioning

confidence: 99%

Bio-Inspired Aerodynamic Noise Control: A Bibliographic Review

Wang

Zhao

et al. 2019

Applied Sciences

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It is well-known that many species of owl have the unique ability to fly silently, which can be attributed to their distinctive and special feather adaptations. Inspired by the owls, researchers attempted to reduce the aerodynamic noise of aircraft and other structures by learning their noise reduction features from different viewpoints and then using the gained knowledge to develop a number of innovative noise reduction solutions. Although fruitful results have been achieved in the bio-inspired aerodynamic noise control, as far as the authors know, comparatively little work has been done to summarize the main findings and progresses in this area. In this bibliographic survey, we systematically review the progresses and trends of the bio-inspired aerodynamic noise control, including the macroscopic and microscopic morphological characteristics of the owl wing feathers, the noise measurements on both flying birds in the field and prepared wings in the wind tunnel, as well as theoretical, numerical and experimental studies that explored the feasibility, parameter influence, aerodynamic effects and underlying mechanisms of the four main bio-inspired noise reduction techniques, i.e., leading edge serrations, trailing edge serrations, fringe-type trailing edge extensions and porous material inspired noise reduction. Finally, we also give some suggestions for future work.

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“…The sidewall effects have been investigated rigorously in our past study (Sun et al. 2019). The sidewalls influence the amplitudes of the Rossiter resonant tones but not the frequencies.…”

Section: Approachesmentioning

confidence: 99%

Unsteady control of supersonic turbulent cavity flow based on resolvent analysis

et al. 2021

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We use resolvent analysis to develop a physics-based, open-loop, unsteady control strategy to attenuate pressure fluctuations in turbulent flow over a rectangular cavity with a length-to-depth ratio of $6$ at a Mach number of $1.4$ and a Reynolds number based on cavity depth of $10\,000$. Large-eddy simulations (LES) of the baseline uncontrolled flow reveal the dominance of Rossiter modes II and IV that generate high-amplitude unsteadiness via trailing-edge impingement and oblique shock waves that obstruct the free stream. To suppress the oscillations, we introduce three-dimensional unsteady blowing along the cavity leading edge. We leverage resolvent analysis as a linear model with respect to the baseline flow to guide the selections of the optimal spanwise wavenumber and frequency of the unsteady actuation input for a fixed momentum coefficient of 0.02. Instead of choosing the most amplified resolvent forcing modes, we seek a disturbance that yields sustained amplification of the primary response mode-based kinetic energy distribution over the entire cavity length. This necessary but not sufficient guideline for effective mean flow modification is evaluated using LES of the controlled cavity flows. The most effective control case reduces the pressure root mean square level up to $52\,\%$ along cavity walls relative to the baseline and is approximately twice that achievable by comparable steady blowing. Dynamic mode decomposition on the controlled flows confirms that the optimal actuation input indeed suppresses the formation of the large-scale Rossiter modes. It is expected that the present flow control guideline derived from resolvent analysis will also be applicable at higher Reynolds numbers with the aid of physical insights and further validation.

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Effects of Sidewalls and Leading-Edge Blowing on Flows over Long Rectangular Cavities

Cited by 36 publications

References 50 publications

Resolvent Analysis of Compressible Laminar and Turbulent Cavity Flows

Resolvent Analysis of Compressible Laminar and Turbulent Cavity Flows

Bio-Inspired Aerodynamic Noise Control: A Bibliographic Review

Unsteady control of supersonic turbulent cavity flow based on resolvent analysis

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