Hybrid RANS-LES simulation of cavity flow fields with control

Arunajatesan, Srinivasan; Shipman, Jeremy; Sinha, Neeraj

doi:10.2514/6.2002-1130

Cited by 43 publications

(18 citation statements)

References 7 publications

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“…The DES cannot build up the right turbulence level in such a short distance downstream of the cylinder. This was also the case in the DES in Arunajatesan et al (2002). Farther downstream (x/L ¼ 3/5 and 4/5), the differences between DES and LES are less visible, but, with respect to the LDV measurements of Illy et al (2004), the LES tends to underestimate wake diffusion, whereas the DES overpredicts it.…”

Section: Analysis Of Resultsmentioning

confidence: 57%

Simulation of the reduction of unsteadiness in a passively controlled transonic cavity flow

Comte

Daude

Mary

2008

Journal of Fluids and Structures

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Section: Analysis Of Resultsmentioning

confidence: 57%

Simulation of the reduction of unsteadiness in a passively controlled transonic cavity flow

Comte

Daude

Mary

2008

Journal of Fluids and Structures

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“…Although both suppression methods reduced peak tones, neither reduced the levels of the broadband contribution. Arunajatesan et al [28] used a hybrid RANS-LES method to study a transverse rod deployed at the lip of the cavity. The rod lifted the shear layer, which no longer impinged on the aft wall.…”

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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“…They stated that the very robust dynamic of the cylinder instability imposes its own dynamics when it is immersed in the region of the cavity leading edge. Arunajatesan et al [11] suggested that the acoustic suppression is related to a possible stabilization of the cavity shear layer due to the change in the mean axial shear layer velocity profiles in presence of the cylinder.…”

Section: Introductionmentioning

confidence: 99%

Passive control of deep cavity shear layer flow at subsonic speed

Hassan

Keirsbulck²

2017

Can. J. Phys.

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Passive control of the flow over a deep cavity at low subsonic velocity is considered in the present paper. The cavity length-to-depth aspect ratio is L/H = 0.2. particle image velocimetry (PIV) measurements characterized the flow over the cavity and show the influence of the control method on the cavity shear layer development. It is found that both the “cylinder” and the “shaped cylinder”, placed upstream from the cavity leading edge, result in the suppression of the aero-acoustic coupling and highly reduce the cavity noise. It should be noted that the vortical structures impinge at almost the same location near the cavity downstream corner with and without passive control. The present study allows to identify an innovative passive flow control method of cavity resonance. Indeed, the use of a “shaped cylinder” presents similar suppression of the cavity resonance as with the “cylinder” but with less impact on the cavity flow. The “shaped cylinder” results in a smaller shear layer growth than the cylinder. Velocity deficiency and turbulence levels are less pronounced using the “shaped cylinder”. The “cylinder” tends to diffuse the vorticity in the cavity shear layer and thus the location of the maximum vorticity is more affected as compared to the “shaped cylinder” control. The fact that the “shaped cylinder” is capable of suppressing the cavity resonance, despite the vortex shedding and the high frequency forcing being suppressed, is of high interest from fundamental and applied points of view.

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Hybrid RANS-LES simulation of cavity flow fields with control

Cited by 43 publications

References 7 publications

Simulation of the reduction of unsteadiness in a passively controlled transonic cavity flow

Simulation of the reduction of unsteadiness in a passively controlled transonic cavity flow

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

Passive control of deep cavity shear layer flow at subsonic speed

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