Quantitative imaging in proper orthogonal decomposition of flow past a delta wing

Cipolla, Kimberly; Rockwell, D.; Liakopoulos, A.

doi:10.2514/3.13959

Cited by 8 publications

(8 citation statements)

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“…To avoid the disadvantages of the isotropic turbulence models based on Boussinesq's assumption we believe that an LES-based model will be appropriate for the problem at hand. Post processing the LES solution with a Proper Orthogonal Decomposition (POD) methodology [21][22][23][24] will reveal the vortical structures that develop near the interface.…”

Section: Discussionmentioning

confidence: 99%

Experiments and Numerical Analysis of Flow in an Open Channel with Gravel Bed

et al. 2018

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Abstract:In this study laboratory experiments and numerical simulations of flow in an open channel with gravel bed of 2 cm thickness are presented and compare. The experimental results were obtained using 2D Particle Image Velocimetry (PIV). For the numerical simulation of gravel bed, a porous layer of thickness 2 cm and appropriate porosity (ε = 0.80, volume of fluid over total porous medium volume) was used. In order to validate the results of the CFX based numerical model, computed quantities are compared with experimental data from PIV measurements. Vertical distributions of velocity above the permeable layer are presented for different total flow depths. The determination of the velocity profiles is of practical importance in the design of open channels. The findings are supported by both laboratory measurements and numerical modelling results and can be useful for engineering applications. In all cases there is a good agreement between experimental and numerical results.

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Section: Discussionmentioning

confidence: 99%

Experiments and Numerical Analysis of Flow in an Open Channel with Gravel Bed

et al. 2018

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“…The most predominant feature is a phase shift between the motion of the wing and the onset of breakdown, as shown by Woffelt, 8 Gilliam et al, 9 Reynolds and Abtahi, 10 Hudson et al, 11 Thompson, 12 Magness et al, 13 Atta and Rockwell, 14 LeMay et al, 15 Jarrah, 16 Ashley et al, 17 and Rockwell;18 all of the foregoing investigations have been for pitching motion. Analogous types of phase shift of breakdown occur for rolling motion of the wing as shown by Hanff and Huang, 19 Ng et al, 20 and Cipolla et al 21 Conceptual features of the complex nature of vortex breakdown, interpreted in the context of experiments, theory, and numerical simulations are provided by the reviews and assessments of Sarpkaya, [22][23][24] Hall,25 Liebovich, 26,27 Escudier, 28 Brown and Lopez, 29 Lopez and Perry, 30 Delery, 31 and Wang and Rusak. 32 From an experimental standpoint, recent efforts have addressed the global, instantaneous features of vortex breakdown.…”

Section: Introductionmentioning

confidence: 85%

Control of vortex breakdown by a transversely oriented wire

2001

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A small wire oriented orthogonally to the axis of the leading-edge vortex on a delta wing at high angle of attack generates substantial changes in the vortex structure, which is characterized using a technique of high-image-density particle image velocimetry. A wire having a diameter two orders of magnitude smaller than the diameter of the leading-edge vortex prior to the onset of vortex breakdown can substantially advance the onset of breakdown by as much as 15 vortex diameters. Depending upon the dimensionless diameter of the wire and wire location along the axis of the vortex, the onset of vortex breakdown can occur either upstream or downstream of the wire. Contours of constant velocity indicate that the rate of decrease of streamwise velocity along the centerline of the vortex is substantially enhanced, even for locations well upstream of the wire, relative to the case of vortex breakdown in the absence of a wire. Patterns of instantaneous vorticity in the presence of the wire typically exhibit a form characteristic of either a spiral- or bubble-like mode of breakdown that occurs in the absence of the wire.

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“…One of the earliest works was on a fully developed pipe flow, studied by Bakewell and Lumley (1967). Since then, POD models have been used to model the one-dimensional Ginzburg-Landau equation (Sirovich and Rodriguez 1987), the laminar-turbulent transitional flow in a flat plate boundary layer (Rempfer 1994), pressure fluctuations surrounding a turbulent jet (Amdt et al 1997), turbulent plane mixing layer (Delville et al 1999), velocity field for an axisymmetric jet (Cifriniti and George 2000), lowdimensionality of a turbulent flow near wake (Ma et al 2000), low-dimensional leading-edge vortices in the unsteady flow past a delta wing (Cipolla et al 1998), and flow over a rectangular cavity (Rowley et al 2000). The eigenfiinctions were developed using both experimental and numerical database.…”

Section: Active Closed-loop Control Of Impingement Tonesmentioning

confidence: 99%

Active Control of Supersonic Impinging Jets Using Supersonic Microjets

Alvi¹

2005

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Quantitative imaging in proper orthogonal decomposition of flow past a delta wing

Cited by 8 publications

References 0 publications

Experiments and Numerical Analysis of Flow in an Open Channel with Gravel Bed

Experiments and Numerical Analysis of Flow in an Open Channel with Gravel Bed

Control of vortex breakdown by a transversely oriented wire

Active Control of Supersonic Impinging Jets Using Supersonic Microjets

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