A hybrid MPI–OpenMP scheme for scalable parallel pseudospectral computations for fluid turbulence

Mininni, Pablo D.; Rosenberg, Duane; Reddy, Raghu; Pouquet, A.

doi:10.1016/j.parco.2011.05.004

Cited by 235 publications

(191 citation statements)

References 12 publications

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“…The code used in this paper is the Geophysical High Order Suite for Turbulence (GHOST), which is fully parallelized using a hybrid methodology [45]. It uses parallel multidimensional FFTs in a pseudo-spectral method for 2D and 3D domains on regular structured grid, and can solve a variety of neutral-fluid partial differential equations, as well as several that include a magnetic field.…”

Section: B Specific Numerical Proceduresmentioning

confidence: 99%

Evidence for Bolgiano-Obukhov scaling in rotating stratified turbulence using high-resolution direct numerical simulations

et al. 2015

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We report results on rotating stratified turbulence in the absence of forcing, with large-scale isotropic initial conditions, using direct numerical simulations computed on grids of up to 4096 3 points. The Reynolds and Froude numbers are respectively equal to Re = 5.4×10 4 and F r = 0.0242. The ratio of the Brunt-Väisälä to the inertial wave frequency, N/f , is taken to be equal to 4.95, a choice appropriate to model the dynamics of the southern abyssal ocean at mid latitudes. This gives a global buoyancy Reynolds number RB = ReF r 2 = 32, a value sufficient for some isotropy to be recovered in the small scales beyond the Ozmidov scale, but still moderate enough that the intermediate scales where waves are prevalent are well resolved. We concentrate on the largescale dynamics, for which we find a spectrum compatible with the Bolgiano-Obukhov scaling, and confirm that the Froude number based on a typical vertical length scale is of order unity, with strong gradients in the vertical. Two characteristic scales emerge from this computation, and are identified from sharp variations in the spectral distribution of either total energy or helicity. A spectral break is also observed at a scale at which the partition of energy between the kinetic and potential modes changes abruptly, and beyond which a Kolmogorov-like spectrum recovers. Large slanted layers are ubiquitous in the flow in the velocity and temperature fields, with local overturning events indicated by small Richardson numbers, and a small large-scale enhancement of energy directly attributable to the effect of rotation is also observed.

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Section: B Specific Numerical Proceduresmentioning

confidence: 99%

Evidence for Bolgiano-Obukhov scaling in rotating stratified turbulence using high-resolution direct numerical simulations

et al. 2015

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“…(1) and (2) were performed in a cubic periodic box using the parallel code GHOST [38][39][40] that uses a pseudospectral method to estimate spatial derivatives, and evolves the system in time using a second-order Runge-Kutta method. Two forcing functions were used: Taylor-Green forcing with F = f 0 (sin x cos y cos zx − cos x sin y cosẑ), and a randomly generated isotropic three-dimensional forcing acting at k = 1.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Absorption of waves by large-scale winds in stratified turbulence

Leoni

Mininni

2015

Phys. Rev. E

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The atmosphere is a nonlinear stratified fluid in which internal gravity waves are present. These waves interact with the flow, resulting in wave turbulence that displays important differences with the turbulence observed in isotropic and homogeneous flows. We study numerically the role of these waves and their interaction with the large scale flow, consisting of vertically sheared horizontal winds. We calculate their space and time resolved energy spectrum (a four-dimensional spectrum), and show that most of the energy is concentrated along a dispersion relation that is Doppler shifted by the horizontal winds. We also observe that when uniform winds are let to develop in each horizontal layer of the flow, waves whose phase velocity is equal to the horizontal wind speed have negligible energy. This indicates a nonlocal transfer of their energy to the mean flow. Both phenomena, the Doppler shift and the absorption of waves traveling with the wind speed, are not accounted for in current theories of stratified wave turbulence.

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“…We use a parallelized pseudo-spectral code [60,61] to solve the Boussinesq equations for an incompressible and stratified fluid:…”

Section: Simulations Of Rotating and Stratified Flowsmentioning

confidence: 99%

Large-scale anisotropy in stably stratified rotating flows

et al. 2014

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We present results from direct numerical simulations of the Boussinesq equations in the presence of rotation and/or stratification, both in the vertical direction. The runs are forced isotropically and randomly at small scales and have spatial resolutions of up to 1024 3 grid points and Reynolds numbers of ≈ 1000. We first show that solutions with negative energy flux and inverse cascades develop in rotating turbulence, whether or not stratification is present. However, the purely stratified case is characterized instead by an early-time, highly anisotropic transfer to large scales with almost zero net isotropic energy flux. This is consistent with previous studies that observed the development of vertically sheared horizontal winds, although only at substantially later times. However, and unlike previous works, when sufficient scale separation is allowed between the forcing scale and the domain size, the total energy displays a perpendicular (horizontal) spectrum with power law behavior compatible with ∼ k −5/3 ⊥ , including in the absence of rotation. In this latter purely stratified case, such a spectrum is the result of a direct cascade of the energy contained in the large-scale horizontal wind, as is evidenced by a strong positive flux of energy in the parallel direction at all scales including the largest resolved scales.

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A hybrid MPI–OpenMP scheme for scalable parallel pseudospectral computations for fluid turbulence

Cited by 235 publications

References 12 publications

Evidence for Bolgiano-Obukhov scaling in rotating stratified turbulence using high-resolution direct numerical simulations

Evidence for Bolgiano-Obukhov scaling in rotating stratified turbulence using high-resolution direct numerical simulations

Absorption of waves by large-scale winds in stratified turbulence

Large-scale anisotropy in stably stratified rotating flows

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