Vortex breakdown simulation: A circumspect study of the steady, laminar, axisymmetric model

Salas, M. D.; Kuruvila, G.

doi:10.1016/0045-7930(89)90020-0

Cited by 24 publications

(14 citation statements)

References 7 publications

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“…With a = 0.05, a sizeable region of supercritical flow exists between the breakdown structure and the inflow boundary, so that the presence of the reversed flow region is not reflected in the conditions specified at the inlet. As observed in several numerical studies of vortex breakdown, including Krause et al (1983), Brown & Lopez (1988) and Salas & Kuruvila (1989), breakdown in a straight pipe inevitable occurs near the inlet. In a time-dependent sense, once a stagnation point forms, the breakdown structure grows and moves upstream until reaching the inlet.…”

Section: Qq == Min [1j(sk' Sk)]'mentioning

confidence: 91%

“…Previous investigations, including that of Salas & Kuruvila (1989) and Beran (1989), have revealed wavetrain solutions with multiple, large regions of reversed flow, apparently free of dispersion errors. Such solutions were not observed in this study; the authors can only speculate that the inability to compute them is due to insufficient grid refinement or the boundary conditions applied.…”

Section: Discussionmentioning

confidence: 99%

“…Kopecky & Torrance (1973) were the first to model vortex breakdown using the N"avier-Stokes equations. Since 1973, results of numerical simulation, using the Navier-Stokes equations, have been reported by Grabowski (1974); Krause, Shi & Hartwich (1983) ;Hafez, Kuruvila & Salas (1986); Beran (1987); Hafez et al (1987); Brown & Lopez (1988) ;Lopez (1988); Menne (1988); Beran (1989); Salas & Kuruvila (1989). Each of these studies assumed the flow to be rotationally symmetric, thereby eliminating the possibility of studying the non-axisymmetric features of vortex breakdown, As emphasized by Faler & Leibovieh (1977), the term axisymmetrie breakdown is a 'misnomer' sinee no breakdown form is truly axisymmetrie.…”

Section: Introductionmentioning

confidence: 99%

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The role of non-uniqueness in the development of vortex breakdown in tubes

1992

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Numerical solutions of viscous, swirling flows through circular pipes of constant radius and circular pipes with throats have been obtained. Solutions were computed for several values of vortex circulation, Reynolds number and throat/inlet area ratio, under the assumptions of steady flow, rotational symmetry and frictionless flow at the pipe wall. When the Reynolds number is sufficiently large, vortex breakdown occurs abruptly with increased circulation as a result of the existence of non-unique solutions. Solution paths for Reynolds numbers exceeding approximately 1000 are characterized by an ensemble of three inviscid flow types: columnar (for pipes of constant radius), soliton and wavetrain. Flows that are quasi-cylindrical and which do not exhibit vortex breakdown exist below a critical circulation, dependent on the Reynolds number and the throat/inlet area ratio. Wave train solutions are observed over a small range of circulation below the critical circulation, while above the critical value, wave solutions with large regions of reversed flow are found that are primarily solitary in nature. The quasi-cylindrical (QC) equations first fail near the critical value, in support of Hall's theory of vortex breakdown (1967). However, the QC equations are not found to be effective in predicting the spatial position ofthe breakdown structure.

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Section: Qq == Min [1j(sk' Sk)]'mentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The role of non-uniqueness in the development of vortex breakdown in tubes

1992

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“…As for numerical simulations of breakdown using the full Navier-Stokes, or inviscid Euler equations, until recently these generally required the assumption of axisymmetry and steadiness of the flow [13][14][15][16]. This is not true of the more recent calculations, for example, those by Kuruvila & Salas [17], Spall et al [18,19], Breuer & Hanel [20], and Menne & Liu [21], all of which solve the unsteady, three-dimensional, fully viscous Navier-Stokes equations (but not all of them are necessarily time-accurate solutions).…”

Section: Introductionmentioning

confidence: 99%

Vortex breakdown incipience: Theoretical considerations

Berger

Erlebacher

1995

Physics of Fluids

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The sensitivity of the onset and the location of vortex breakdowns in concentrated vortex cores, and the pronounced tendency of the breakdowns to move upstream have been characteristic observations of experimental investigations; they have also been features of numerical simulations and led to questions about the validity of these simulations. This movement upstream may be a migration in time for fixed values of the relevant parameters, or the movement of the breakdown location closer to the entrance to the flow or computational domain with small changes in these parameters. This behavior seems to be inconsistent with the strong time-like axial evolution of the flow, as expressed explicitly, for example, by the quasicylindrical approximate equations for this flow. An order-of-magnitude analysis of the equations of motion near breakdown leads to a modified set of governing equations, analysis of which demonstrates that the interplay between radial inertial, pressure, and viscous forces gives an elliptic character to these concentrated swirling flows. Analytical, asymptotic, and numerical solutions of a simplified nonlinear equation are presented; these qualitatively exhibit the features of vortex onset and location noted above.

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“…Longitudinal vortex/transverse shock-wave interactions am typical applications which appear in transonic and supersonic flows over a strake-wing configuration at moderate-high angles of attack, at a supersonic inlet injesting a vortex and inside a supersonic combustor where fuel is injected in a swirling jet to enhance fuel-air mixing [1]- [3]. For the strake-wing configuration, vortex breakdown is undesirable since it results in the stall phenomenon, and hence its occurrence need to be delayed.…”

Section: Introductionmentioning

confidence: 99%