scholarly journals Spatio-temporal correlations in three-dimensional homogeneous and isotropic turbulence

2021 ◽  
Vol 33 (4) ◽  
pp. 045114
Author(s):  
A. Gorbunova ◽  
G. Balarac ◽  
L. Canet ◽  
G. Eyink ◽  
V. Rossetto
Keyword(s):  
Isotropic Turbulence ◽  
Three Dimensional ◽  
Temporal Correlations ◽  
Homogeneous And Isotropic Turbulence ◽  
Spatio Temporal

scholarly journals Lagrangian cascade in three-dimensional homogeneous and isotropic turbulence

2014 ◽  
Vol 741 ◽  
Author(s):  
Yongxiang Huang ◽  
François G. Schmitt
Keyword(s):  
Dissipation Rate ◽  
Isotropic Turbulence ◽  
Three Dimensional ◽  
Energy Dissipation Rate ◽  
Inertial Range ◽  
Order Moment ◽  
Scaling Exponent ◽  
Tracer Particles ◽  
Homogeneous And Isotropic Turbulence ◽  
Multiplicative Cascade

AbstractIn this work, the scaling statistics of the dissipation along Lagrangian trajectories are investigated by using fluid tracer particles obtained from a high-resolution direct numerical simulation with $\mathit{Re}_{\lambda }=400$. Both the energy dissipation rate $\epsilon $ and the local time-averaged $\epsilon _{\tau }$ agree rather well with the lognormal distribution hypothesis. Several statistics are then examined. It is found that the autocorrelation function $\rho (\tau )$ of $\ln (\epsilon (t))$ and variance $\sigma ^2(\tau )$ of $\ln (\epsilon _{\tau }(t))$ obey a log-law with scaling exponent $\beta '=\beta =0.30$ compatible with the intermittency parameter $\mu =0.30$. The $q{\rm th}$-order moment of $\epsilon _{\tau }$ has a clear power law on the inertial range $10<\tau /\tau _{\eta }<100$. The measured scaling exponent $K_L(q)$ agrees remarkably with $q-\zeta _L(2q)$ where $\zeta _L(2q)$ is the scaling exponent estimated using the Hilbert methodology. All of these results suggest that the dissipation along Lagrangian trajectories could be modelled by a multiplicative cascade.

scholarly journals Design and Validation of a Probe for Spatially and Temporally Resolved Measurements of Vorticity and Strain Rates in Compressible Turbulence Interactions

10.14311/994 ◽  
2007 ◽  
Vol 47 (6) ◽  
Author(s):  
S. Xanthos ◽  
M. Gong ◽  
Y. Andreopoulos
Keyword(s):  
Isotropic Turbulence ◽  
Strain Tensor ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Compressible Turbulence ◽  
Expansion Waves ◽  
Custom Made ◽  
Homogeneous And Isotropic Turbulence ◽  
Total Temperature ◽  
Kinetic Energy Term

A custom-made hot-wire vorticity probe was designed and developed capable of measuring the time-dependent highly fluctuating three dimensional velocity and vorticity vectors, and associated total temperature, in non-isothermal and inhomogeneous flows with reasonable spatial and temporal resolution. These measurements allowed computation of the vorticity stretching/tilting terms, vorticity generation through dilatation terms, full dissipation rate of the kinetic energy term and full rate-of-strain tensor. The probe has been validated experimentally in low-speed boundary layers and used in the CCNY Shock Tube Research Facility, where interactions of planar expansion waves or shock waves with homogeneous and isotropic turbulence have been investigated at several Reynolds numbers. 

The Turbulent Schmidt Number

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Diego A. Donzis ◽  
Konduri Aditya ◽  
K. R. Sreenivasan ◽  
P. K. Yeung
Keyword(s):  
Schmidt Number ◽  
Isotropic Turbulence ◽  
Functional Dependence ◽  
Three Dimensional ◽  
Passive Scalars ◽  
Turbulent Schmidt Number ◽  
Schmidt Numbers ◽  
Homogeneous And Isotropic Turbulence ◽  
Homogeneous Mean ◽  
Parameter Ranges

We analyze a large database generated from recent direct numerical simulations (DNS) of passive scalars sustained by a homogeneous mean gradient and mixed by homogeneous and isotropic turbulence on grid resolutions of up to 40963 and extract the turbulent Schmidt number over large parameter ranges: the Taylor microscale Reynolds number between 8 and 650 and the molecular Schmidt number between 1/2048 and 1024. While the turbulent Schmidt number shows considerable scatter with respect to the Reynolds and molecular Schmidt numbers separately, it exhibits a sensibly unique functional dependence with respect to the molecular Péclet number. The observed functional dependence is motivated by a scaling argument that is standard in the phenomenology of three-dimensional turbulence.

scholarly journals Split energy–helicity cascades in three-dimensional homogeneous and isotropic turbulence

2013 ◽  
Vol 730 ◽  
pp. 309-327 ◽  
Author(s):  
L. Biferale ◽  
S. Musacchio ◽  
F. Toschi
Keyword(s):  
Degrees Of Freedom ◽  
Isotropic Turbulence ◽  
Three Dimensional ◽  
Thin Layers ◽  
Energy Cascade ◽  
Navier Stokes ◽  
Inverse Energy Cascade ◽  
Negative Helicity ◽  
Homogeneous And Isotropic Turbulence ◽  
Transfer Properties

AbstractWe investigate the transfer properties of energy and helicity fluctuations in fully developed homogeneous and isotropic turbulence by changing the nature of the nonlinear Navier–Stokes terms. We perform a surgery of all possible interactions, by keeping only those triads that have sign-definite helicity content. In order to do this, we apply an exact decomposition of the velocity field in a helical Fourier basis, as first proposed by Constantin & Majda (Commun. Math. Phys, vol. 115, 1988, p. 435) and exploited in great detail by Waleffe (Phys. Fluids A, vol. 4, 1992, p. 350), and we evolve the Navier–Stokes dynamics keeping only those velocity components carrying a well-defined (positive or negative) helicity. The resulting dynamics preserves translational and rotational symmetries but not mirror invariance. We give clear evidence that this three-dimensional homogeneous and isotropic chiral turbulence is characterized by a stationary inverse energy cascade with a spectrum ${E}_{back} (k)\sim {k}^{- 5/ 3} $ and by a direct helicity cascade with a spectrum ${E}_{forw} (k)\sim {k}^{- 7/ 3} $. Our results are important to highlight the dynamics and statistics of those subsets of all possible Navier–Stokes interactions responsible for reversal events in the energy-flux properties, and demonstrate that the presence of an inverse energy cascade is not necessarily connected to a two-dimensionalization of the flow. We further comment on the possible relevance of such findings to flows of geophysical interest under rotations and in thin layers. Finally we propose other innovative numerical experiments that can be achieved by using a similar decimation of degrees of freedom.

On the scaling of three-dimensional homogeneous and isotropic turbulence

1995 ◽  
Vol 80 (4) ◽  
pp. 385-398 ◽  
Author(s):  
Roberto Benzi ◽  
Sergio Ciliberto ◽  
Cristophe Baudet ◽  
Gerardo Ruiz Chavarria
Keyword(s):  
Isotropic Turbulence ◽  
Three Dimensional ◽  
Homogeneous And Isotropic Turbulence
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