Unsteady supersonic cavity flow simulations using coupled k-epsilon and Navier-Stokes equations

Shih, S. H.; Hamed, A.; Yeuan, J. J.

doi:10.2514/3.12246

Cited by 51 publications

(10 citation statements)

References 12 publications

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“…models were made. Most references to cavity-flow modeling with two-equation models were related to supersonic flow conditions [35,36], whereas applications of two-equation models to transonic cavity flows are rare. A detailed survey of published works on cavity flow can be found in [2].…”

Section: A Experimental Studiesmentioning

confidence: 99%

Assessment of Passive Flow Control for Transonic Cavity Flow Using Detached-Eddy Simulation

Lawson

Barakos

2009

Journal of Aircraft

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The implementation of internal store carriage on stealthy military aircraft has accelerated research into transonic cavity flows. Depending on the freestream Mach number and the cavity dimensions, flows inside cavities can become unsteady, threatening the structural integrity of the cavity and its contents (e.g., stores, avionics, etc.). Below a critical length-to-depth ratio, the shear layer formed along the cavity mouth has enough energy to span across the opening. This shear layer impacts the downstream cavity corner and the generated acoustic disturbances propagate upstream, causing further instabilities near the cavity front. Consequently, a self-sustained feedback loop is established. This extreme flow environment calls for flow control ideas aiming to pacify the cavity by breaking the feedback loop and controlling the breakdown of the shear layer. This is the objective of the present work, which aims to assess changes of the cavity geometry and their effect on the resulting flow using detached-eddy simulation. For the cases computed in this work, quantitative and qualitative agreement with experimental data has been obtained. All of the devices tested achieved similar reductions in overall sound pressure level in the rear half of the cavity; however, a slanted aft wall provided the largest noise reduction in the front half of the cavity. Nomenclature A = wall area, m 2 a i t = temporal eigenfunctions C F = force coefficient D = cavity depth, m F, G, H = spatial flux vectors in Navier-Stokes equations f = frequency, Hz L = cavity length, m N = number of snapshots for proper orthogonal decomposition p = pressure, Pa p 0 = unsteady pressure, Pa Q = unsteady terms in Navier-Stokes equations q 1 = freestream dynamic pressure ( 1 2 1 U 2 1 ), Pa Re = Reynolds number Re L = Reynolds number based on cavity length L S = symmetric components of the velocity gradient tensor [Eq. (7)] S = source vector in Navier-Stokes equations [Eq. (1)] T Rossiter1 = time period of the lowest Rossiter mode, s t = time, s u = velocity, m=s x, y, z = Cartesian coordinates, m i = matrix eigenvalues = density, kg=m 3 i x = spatial eigenfunctions = antisymmetric component of the velocity gradient tensor Subscripts rms = root mean square m = mean quantity 1 = freestream value Superscripts inv = inviscid term vis = viscous term

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Section: A Experimental Studiesmentioning

confidence: 99%

Assessment of Passive Flow Control for Transonic Cavity Flow Using Detached-Eddy Simulation

Lawson

Barakos

2009

Journal of Aircraft

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“…Modes can be predicted well by improved versions of his formula (Heller and Bliss, 1975;Bauer and Dix, 1991), but no simple analytic formula exists for predicting the associated amplitudes of the fluctuating pressure. There are experimental (Kegerise, 1999;Leu and Dolling, 1997;Unalmis et al, 1999) and computational (Shih et al, 1994;Lillberg and Fureby, 2000;Hamed et al, 2003;Rizzetta and Visbal, 2003;Zhang and Edwards, 1996;Tam et al, 1996;Takakura et al, 1996;Aradag and Kinght, 2005) studies performed on cavity flow. Most of the computational studies in literature related to the physics of the supersonic flow over a cavity and analysis of the flow in two dimensions (Zhang and Edwards, 1996;Tam et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Two and Three Dimensional Simulations of Supersonic Cavity Configurations

Aradağ

Kim

Knight

2010

Engineering Applications of Computational Fluid Mechanics

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The flow over cavities can produce complex unsteady flowfields that are an important practical concern in aerospace applications. Understanding the flow field in the cavity can help to determine the driving mechanism of the oscillations to create effective control methods to avoid structural damage. In this study, both two and three dimensional time-dependent Reynolds-Averaged Navier-Stokes simulations are performed for the flow over an open cavity to demonstrate the capability of computational fluid dynamics to accurately predict the supersonic flow field inside a cavity and to assess the adequacy of two dimensional simulations in capturing cavity flow physics accurately. In this particular problem of a supersonic flow over a cavity, the three-dimensional effects cannot be neglected. A two-dimensional simulation would give an insight about the longitudinal mode of the cavity flow without any three-dimensional effects, but it is not enough to understand the real physics of the problem.

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“…Specifically, the statistical velocity profiles and vortex structures in the turbulent region are widely used to demonstrate the effectiveness of numerical and experimental methods 1 in the study of flat plates, 2,3 back/forward-facing steps, 4 and cavity flows. 5 The enhancement of computing power in recent decades has led to rapid advances in high-fidelity methods such as the Large eddy simulation (LES), implicit LES (ILES), detached eddy simulation (DES), and Direct Numerical Simulation (DNS), 6,7 as well as their applications to turbulent flowfield simulations. 8 The aero-optical effect is a multi-disciplinary issue that refers to the distortions of optical signals and image aberrations induced by turbulent flows adjacent to a projection or viewing aperture when an aircraft flies at high speeds.…”

Section: Introductionmentioning

confidence: 99%

Validation case for supersonic boundary layer and turbulent aero-optical investigation in high-Reynolds-number freestream by WCNS-E-5

Sun

Liu

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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Turbulent flat-plate boundary layer flows have been widely employed for numerical validation in the aero-optical field. In present study, the laminar-to-turbulent evolution induced by wavy roughness in high-Reynolds-number supersonic freestream is investigated using a numerical technique based on the fifth-order weighted compact nonlinear scheme (WCNS-E-5). The computational procedure and post-processing method are described in detail, and the acquired instantaneous flow structure and statistical data are compared with other theoretical, experimental, and numerical results to demonstrate the feasibility of predicting turbulence using WCNS-E-5. Further, to reduce the computational resources required to simulate turbulent flow, a velocity correlation function is introduced to decrease the computational domain in the spanwise direction. Additionally, the effects of different grid sizes on the simulation results are examined by reducing the number of cells in the streamwise, wall-normal, and spanwise directions. Finally, the authors conduct a tentative investigation into the aero-optical effects of the laminar-to-turbulent flowfield using a ray-tracing method, considering both the feasibility of aero-optical detection and the effect of grid scale on the time-averaged imaging quality, as well as a deeper probe into the characteristic structures reflected by aero-optical frequency spectrum. The results elucidated that the wall-normal grid number has the strongest influence on the transitional location, and undoubtedly affects wavefront aberrations. However, different gird scales lead to similar aero-optical spectrum, and revealed the Kolmogorov-type turbulence at small-scale regime. As a prelude to further aero-optical simulations of wall-bounded flows, the current study provides some reference for the code validation process and aero-optical interrogation.

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Unsteady supersonic cavity flow simulations using coupled k-epsilon and Navier-Stokes equations

Cited by 51 publications

References 12 publications

Assessment of Passive Flow Control for Transonic Cavity Flow Using Detached-Eddy Simulation

Assessment of Passive Flow Control for Transonic Cavity Flow Using Detached-Eddy Simulation

Two and Three Dimensional Simulations of Supersonic Cavity Configurations

Validation case for supersonic boundary layer and turbulent aero-optical investigation in high-Reynolds-number freestream by WCNS-E-5

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