Direct and large-eddy simulations of axisymmetric wakes

Tomboulides, Ananias; Orszag, Steven A.; Karniadakis, George Em

doi:10.2514/6.1993-546

Cited by 85 publications

(89 citation statements)

References 9 publications

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“…Finally, the length of the standing eddy (L e ) measured from the base of the sphere is also compared with the numerical results of Pruppacher et al [36] and very good agreement is observed. The corresponding values obtained by Tomboulides et al [21] have also been shown in the table and it is found that their values are somewhat underpredicted at the lower Reynolds numbers.…”

Section: Axisymmetric Simulationssupporting

confidence: 53%

A Fourier-Chebyshev spectral collocation method for simulating flow past spheres and spheroids

Mittal

1999

Int. J. Numer. Meth. Fluids

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An accurate Fourier -Chebyshev spectral collocation method has been developed for simulating flow past prolate spheroids. The incompressible Navier-Stokes equations are transformed to the prolate spheroidal co-ordinate system and discretized on an orthogonal body fitted mesh. The infinite flow domain is truncated to a finite extent and a Chebyshev discretization is used in the wall-normal direction. The azimuthal direction is periodic and a conventional Fourier expansion is used in this direction. The other wall-tangential direction requires special treatment and a restricted Fourier expansion that satisfies the parity conditions across the poles is used. Issues including spatial and temporal discretization, efficient inversion of the pressure Poisson equation, outflow boundary condition and stability restriction at the pole are discussed. The solver has been validated primarily by simulating steady and unsteady flow past a sphere at various Reynolds numbers and comparing key quantities with corresponding data from experiments and other numerical simulations.

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Section: Axisymmetric Simulationssupporting

confidence: 53%

A Fourier-Chebyshev spectral collocation method for simulating flow past spheres and spheroids

Mittal

1999

Int. J. Numer. Meth. Fluids

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“…The sign of the ratio d/b u (Table II and indeed for all computations) indicates that these pitchfork bifurcations are supercritical (see Lemma 2.3.1), a result that is consistent with both the experimental evidence of Margarvey and Bishop [3], Nakamura [4] and Wu and Faeth [5], the computational evidence of Tomboulides et al [7] and the conjecture of Natarajan and Acrivos [6]. It could not be determined by the earlier eigenvalue computations alone.…”

Section: Resultssupporting

confidence: 77%

“…More recent experimental investigations by Goldburg and Florsheim [2], Margarvey and Bishop [3], Nakamura [4] and Wu and Faeth [5], and computational studies by Natarajan and Acrivos [6], Tomboulides et al [7] and Tavener [8], have all concluded that the initially steady axisymmetric flow past the sphere loses stability to a steady, asymmetric flow above a critical flow rate. The experimental studies and the computations of Tomboulides et al [7] have shown that this steady asymmetric flow in turn loses stability to a time-dependent flow with a further small increase in the flow rate.…”

Section: Introductionmentioning

confidence: 99%

O(2)-symmetry breaking bifurcation: with application to the flow past a sphere in a pipe

Cliffe

Spence

Tavener

2000

Int. J. Numer. Meth. Fluids

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“…The low Reynolds number precursor structures have been observed previously in the dye visualisations of the wake of a liquid drop of Magarvey & Bishop (1961), and further experiments of Sakamoto & Haniu (1990), Leweke et al (1999) and Ormières & Provansal (1999). Interlinked vortex loops have also been reported in numerical simulations concerning the wake of a static sphere by Tomboulides, Orszag & Karniadakis (1993), Johnson & Patel (1999), Mittal (1999) and Thompson, Leweke & Provansal (2001).…”

Section: Modes Of Vortex Formationsupporting

confidence: 71%

Vortex-induced vibration of a rotating sphere

et al. 2017

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. Vortex-induced vibration (VIV) of a sphere represents one of the most generic fundamental fluid-structure interaction problems. Since vortex-induced vibration can lead to structural failure, numerous studies have focused on understanding the underlying principles of VIV and its suppression. This paper reports on an experimental investigation of the effect of imposed axial rotation on the dynamics of vortex-induced vibration of a sphere that is free to oscillate in the cross-flow direction, by employing simultaneous displacement and force measurements. The VIV response was investigated over a wide range of reduced velocities (i.e. velocity normalised by the natural frequency of the system): 3 U * 18, corresponding to a Reynolds number range of 5000 < Re < 30 000, while the rotation ratio, defined as the ratio between the sphere surface and inflow speeds, α = |ω|D/(2U), was varied in increments over the range of 0 α 7.5. It is found that the vibration amplitude exhibits a typical inverted bell-shaped variation with reduced velocity, similar to the classic VIV response for a non-rotating sphere but without the higher reduced velocity response tail. The vibration amplitude decreases monotonically and gradually as the imposed transverse rotation rate is increased up to α = 6, beyond which the body vibration is significantly reduced. The synchronisation regime, defined as the reduced velocity range where large vibrations close to the natural frequency are observed, also becomes narrower as α is increased, with the peak saturation amplitude observed at progressively lower reduced velocities. In addition, for small rotation rates, the peak amplitude decreases almost linearly with α. The imposed rotation not only reduces vibration amplitudes, but also makes the body vibrations less periodic. The frequency spectra revealed the occurrence of a broadband spectrum with an increase in the imposed rotation rate. Recurrence analysis of the structural vibration response demonstrated a transition from periodic to chaotic in a modified recurrence map complementing the appearance of broadband spectra at the onset of bifurcation. Despite considerable changes in flow structure, the vortex phase (φ vortex ), defined as the phase between the vortex force and the body displacement, follows the same pattern as for the non-rotating case, with the φ vortex increasing gradually from low values in Mode I of the sphere vibration to almost 180• as the system undergoes a continuous transition to Mode II of the sphere vibration at higher reduced velocity. The total phase (φ total ), defined as the phase between the transverse lift force and the body displacement, only increases from low values after the peak amplitude † Email address for correspondence: jisheng.zhao@monash.edu response in Mode II has been reached. It reaches its maximum value (∼165• ) close to the transition from the Mode II upper plateau t...

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Direct and large-eddy simulations of axisymmetric wakes

Cited by 85 publications

References 9 publications

A Fourier-Chebyshev spectral collocation method for simulating flow past spheres and spheroids

A Fourier-Chebyshev spectral collocation method for simulating flow past spheres and spheroids

O(2)-symmetry breaking bifurcation: with application to the flow past a sphere in a pipe

Vortex-induced vibration of a rotating sphere

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