Gregory P. Chini
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View article: Baroclinic transition in acoustic streaming: beyond Rayleigh’s paradigm
Baroclinic transition in acoustic streaming: beyond Rayleigh’s paradigm Open
Standing acoustic waves in a channel generate time-mean Eulerian flows. In homogeneous fluids, these streaming flows have been shown by Rayleigh to result from viscous attenuation of the waves in oscillatory boundary (i.e. Stokes) layers. …
View article: Following marginal stability manifolds in quasilinear dynamical reductions of multiscale flows in two space dimensions
Following marginal stability manifolds in quasilinear dynamical reductions of multiscale flows in two space dimensions Open
We derive a two-dimensional (2D) extension of a recently developed formalism for slow-fast quasilinear (QL) systems subject to fast instabilities. The emergent dynamics of these systems is characterized by a slow evolution of (suitably def…
View article: Regimes of stratified turbulence at low Prandtl number
Regimes of stratified turbulence at low Prandtl number Open
Quantifying transport by strongly stratified turbulence in low Prandtl number ( $Pr$ ) fluids is critically important for the development of better models for the structure and evolution of stellar and planetary interiors. Motivated by rec…
View article: Aspect-ratio-dependent heat transport by baroclinic acoustic streaming
Aspect-ratio-dependent heat transport by baroclinic acoustic streaming Open
Standing acoustic waves have been known to generate Eulerian time-mean ‘streaming’ flows at least since the seminal investigation of Lord Rayleigh in the 1880s. Nevertheless, a recent body of numerical and experimental evidence has shown t…
View article: Following marginal stability manifolds in quasilinear dynamical reductions of multiscale flows in two space dimensions
Following marginal stability manifolds in quasilinear dynamical reductions of multiscale flows in two space dimensions Open
A two-dimensional extension of a recently developed formalism for slow-fast quasilinear (QL) systems subject to fast instabilities is derived. Prior work has demonstrated that the emergent dynamics of these systems is characterized by a sl…
View article: Regimes of stratified turbulence at low Prandtl number
Regimes of stratified turbulence at low Prandtl number Open
Quantifying transport by strongly stratified turbulence in low Prandtl number ($Pr$) fluids is critically important for the development of better models for the structure and evolution of stellar and planetary interiors. Motivated by recen…
View article: Spatio-temporal characterization of non-linear forcing in turbulence
Spatio-temporal characterization of non-linear forcing in turbulence Open
The quadratic convection term in the incompressible Navier-Stokes equations is considered as a non-linear forcing to the linear operator, and it is studied in the Fourier domain through the analysis of interactions between triadically comp…
View article: Exploiting self-organized criticality in strongly stratified turbulence
Exploiting self-organized criticality in strongly stratified turbulence Open
A multiscale reduced description of turbulent free shear flows in the presence of strong stabilizing density stratification is derived via asymptotic analysis of the Boussinesq equations in the simultaneous limits of small Froude and large…
View article: FLM volume 911 Cover and Front matter
FLM volume 911 Cover and Front matter Open
International audience
View article: A self-sustaining process theory for uniform momentum zones and internal shear layers in high Reynolds number shear flows
A self-sustaining process theory for uniform momentum zones and internal shear layers in high Reynolds number shear flows Open
View article: Steady coherent convection between stress-free boundaries
Steady coherent convection between stress-free boundaries Open
Steady two-dimensional Rayleigh--Benard convection between stress-free isothermal boundaries is studied via numerical computations. We explore properties of steady convective rolls with aspect ratios $\pi/5\le\Gamma\le4\pi$, where $\Gamma$…
View article: A self-sustaining process theory for uniform momentum zones and internal\n shear layers in high Reynolds number shear flows
A self-sustaining process theory for uniform momentum zones and internal\n shear layers in high Reynolds number shear flows Open
Many exact coherent states (ECS) arising in wall-bounded shear flows have an\nasymptotic structure at extreme Reynolds number Re in which the effective\nReynolds number governing the streak and roll dynamics is O(1). Consequently,\nthese v…
View article: On Moderate-Rayleigh-Number Convection in an Inclined Porous Layer
On Moderate-Rayleigh-Number Convection in an Inclined Porous Layer Open
We investigate the flow structure and dynamics of moderate-Rayleigh-number ( R a ) thermal convection in a two-dimensional inclined porous layer. High-resolution numerical simulations confirm the emergence of O ( 1 ) aspect-ratio large-sca…
View article: On Moderate-Rayleigh-Number Convection in an Inclined Porous Layer
On Moderate-Rayleigh-Number Convection in an Inclined Porous Layer Open
We investigate the flow structure and dynamics of moderate-Rayleigh-number ($Ra$) thermal convection in a two-dimensional inclined porous layer. Direct numerical simulations (DNS) confirm the emergence of $\mathit{O}(1)$ aspect-ratio large…
View article: Multiple scales analysis of slow–fast quasi-linear systems
Multiple scales analysis of slow–fast quasi-linear systems Open
This article illustrates the application of multiple scales analysis to two archetypal quasi-linear systems; i.e. to systems involving fast dynamical modes, called fluctuations, that are not directly influenced by fluctuation–fluctuation n…
View article: Supplementary Material from Multiple scales analysis of slow–fast quasi-linear systems
Supplementary Material from Multiple scales analysis of slow–fast quasi-linear systems Open
This article illustrates the application of multiple scales analysis to two archetypal quasi-linear systems; i.e. to systems involving fast dynamical modes, called fluctuations, that are not directly influenced by fluctuation–fluctuation n…
View article: Strong wave–mean-flow coupling in baroclinic acoustic streaming
Strong wave–mean-flow coupling in baroclinic acoustic streaming Open
The interaction of an acoustic wave with a stratified fluid can drive strong streaming flows owing to the baroclinic production of fluctuating vorticity, as recently demonstrated by Chini et al. ( J. Fluid Mech. , 744 , 2014, pp. 329–351).…
View article: The influence of a poroelastic till on rapid subglacial flooding and cavity formation
The influence of a poroelastic till on rapid subglacial flooding and cavity formation Open
We develop a model of the rapid propagation of water at the contact between elastic glacial ice and a poroelastic subglacial till, motivated by observations of the rapid drainage of supraglacial lakes in Greenland. By treating the ice as a…
View article: A self-sustaining process model of inertial layer dynamics in high Reynolds number turbulent wall flows
A self-sustaining process model of inertial layer dynamics in high Reynolds number turbulent wall flows Open
Field observations and laboratory experiments suggest that at high Reynolds numbers Re the outer region of turbulent boundary layers self-organizes into quasi-uniform momentum zones (UMZs) separated by internal shear layers termed ‘vortica…
View article: Prospectus: towards the development of high-fidelity models of wall turbulence at large Reynolds number
Prospectus: towards the development of high-fidelity models of wall turbulence at large Reynolds number Open
Recent and on-going advances in mathematical methods and analysis techniques, coupled with the experimental and computational capacity to capture detailed flow structure at increasingly large Reynolds numbers, afford an unprecedented oppor…
View article: Generalized Quasilinear Approximation: Application to Zonal Jets
Generalized Quasilinear Approximation: Application to Zonal Jets Open
Quasilinear theory is often utilized to approximate the dynamics of fluids exhibiting significant interactions between mean flows and eddies. We present a generalization of quasilinear theory to include dynamic mode interactions on the lar…
View article: Exact coherent structures at extreme Reynolds number
Exact coherent structures at extreme Reynolds number Open
Exact coherent structures (ECS), unstable three-dimensional solutions of the Navier–Stokes equations, play a fundamental role in transitional and turbulent wall flows. Dempsey et al. ( J. Fluid Mech. , vol. 791, 2016, pp. 97–121) demonstra…
View article: Time-stepping approach for solving upper-bound problems: Application to two-dimensional Rayleigh-Bénard convection
Time-stepping approach for solving upper-bound problems: Application to two-dimensional Rayleigh-Bénard convection Open
An alternative computational procedure for numerically solving a class of variational problems arising from rigorous upper-bound analysis of forced-dissipative infinite-dimensional nonlinear dynamical systems, including the Navier-Stokes a…
View article: Reduced description of exact coherent states in parallel shear flows
Reduced description of exact coherent states in parallel shear flows Open
A reduced description of exact coherent structures in the transition regime of plane parallel shear flows is developed, based on the Reynolds number scaling of streamwise-averaged (mean) and streamwise-varying (fluctuation) velocities obse…
View article: Dynamic patterns in the reduced Craik–Leibovich equations
Dynamic patterns in the reduced Craik–Leibovich equations Open
Numerical simulations of an asymptotically reduced version of the Craik–Leibovich (CL) equations are described. By filtering surface waves, the CL equations facilitate simulations of surface-wave driven or surface-wave modified phenomena i…