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Stochastic wind sea is an intermediate small-scale physical process responsible for the state of the atmospheric boundary layer and the water upper layer, having dynamics of all scales. To describe behavior of this system, one could use the…

Atmospheric and Oceanic Physics · Physics 2010-09-13 Vladislav Polnikov

We consider the wind-forced nonlinear Schroedinger (NLS) equation obtained in the potential flow framework when the Miles growth rate is of the order of the wave steepness. In this case, the form of the wind-forcing terms gives rise to the…

Atmospheric and Oceanic Physics · Physics 2015-06-23 Maura Brunetti , Jérôme Kasparian

Recently, Nagib et al (2024} utilized indicator functions of profiles of the streamwise normal stress to reveal the ranges of validity, in wall distance and Reynolds number, for each of two proposed models in DNS of channel and pipe flows.…

Fluid Dynamics · Physics 2024-11-20 Hassan Nagib , Ivan Marusic

Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for non-thermal features to survive, which suggests…

Space Physics · Physics 2017-05-19 Daniel Verscharen , Christopher H. K. Chen , Robert T. Wicks

Using the Lagrangian transport analysis for the turbulence momentum, the Reynolds stress gradient can be expressed as a function of the local momentum flux and force terms. From this perspective of an observer moving at the local mean…

Fluid Dynamics · Physics 2024-07-09 T. W. Lee , J. E. Park

Wave interaction theory can be used as a tool to understand and predict instability in a variety of homogeneous and stratified shear flows. It is however, most often limited to piecewise-linear profiles of the shear layer background…

Fluid Dynamics · Physics 2019-09-04 Jeff Carpenter , Anirban Guha

A statistical mechanics theory for a fluid stratified in density is presented. The predicted statistical equilibrium state is the most probable outcome of turbulent stirring. The slow temporal evolution of the vertical density profile is…

Fluid Dynamics · Physics 2014-09-23 Antoine Venaille , Louis Gostiaux , Joël Sommeria

Recent experimental observations at JET show evidence of reduced ion temperature profile stiffness, hypothesised to be due to concomitant low magnetic shear (s) and significant toroidal rotational flow shear. Non-linear gyrokinetic…

For low enough flow rates, turbulent channel flow displays spatial modulations of large wavelengths. This phenomenon has recently been interpreted as a linear instability of the turbulent flow. We question here the ability of linear…

Fluid Dynamics · Physics 2024-06-21 P. V. Kashyap , Y. Duguet , O. Dauchot

We study the experimental properties of exchange flows in a stratified inclined duct (SID), which are simultaneously turbulent, strongly stratified by a mean vertical density gradient, driven by a mean vertical shear, and continuously…

Fluid Dynamics · Physics 2022-03-14 Adrien Lefauve , P. F. Linden

Instabilities at interface of two stream granular flows have been reported in recent experiment [1] that breaking waves can form at the interface between two streams of identical grains flowing on an inclined plane downstream of a splitter…

Classical Physics · Physics 2007-05-23 Hua-Shu Dou , Boo Cheong Khoo , Nhan Phan-Thien

When submitted to the repeated passages of vehicles unpaved roads made of sand or gravel can develop a ripply pattern known as washboard or corrugated road. We propose a stability analysis based on experimental measurements of the force…

Soft Condensed Matter · Physics 2013-01-21 Baptiste Percier , Sébastien Manneville , Nicolas Taberlet

We describe experiments that probe the evolution of shear jammed states, occurring for packing fractions $\phi_S \leq \phi \leq \phi_J$, for frictional granular disks, where above $\phi_J$ there are no stress-free static states. We use a…

Soft Condensed Matter · Physics 2015-06-05 Jie Ren , Joshua A. Dijksman , Robert P. Behringer

Wave-particle instabilities driven by departures from local thermodynamic equilibrium have been conjectured to play a role in governing solar wind dynamics. We calculate the statistical variation of linear stability over a large subset of…

Solar and Stellar Astrophysics · Physics 2020-01-08 Kristopher G. Klein , Mihailo Martinovic , David Stansby , Timothy S. Horbury

Laminar-turbulent transition on a rotating wind turbine blade at a chord Reynolds number of $1 \times 10^5$ and varying angles of attack ($AoA$) is studied with direct numerical simulations and linear stability theory. The rotation effects…

Fluid Dynamics · Physics 2023-08-01 Thales Coelho Leite Fava , Dan Henningson , Ardeshir Hanifi

To aid in prediction of turbulent boundary layer flows over rough surfaces, a new model is proposed to estimate hydrodynamic roughness based solely on geometric surface information. The model is based on a fluid-mechanics motivated…

Fluid Dynamics · Physics 2024-12-18 Charles Meneveau , Nicholas Hutchins , Daniel Chung

A linear stability analysis is performed on a tilted parallel wake in a strongly stratified fluid at low Reynolds numbers. A particular emphasis of the present study is given to the understanding of the low-Froude-number mode observed by…

Fluid Dynamics · Physics 2019-09-26 Lloyd Fung , Yongyun Hwang

We present nonlinear three-dimensional simulations of the stably-stratified portion of the solar tachocline in which the rotational shear is maintained by mechanical forcing. When a broad toroidal field profile is specified as an initial…

Astrophysics · Physics 2009-11-13 Mark S. Miesch

Shear strain localization into shear bands is associated with velocity weakening instabilities and earthquakes. Here, we simulate steady-state plane-shear flow of numerical granular material (gouge), confined between parallel surfaces. Both…

Soft Condensed Matter · Physics 2021-11-09 Stanislav Parez , Tereza Travnickova , Martin Svoboda , Einat Aharonov

Resistive tearing instabilities are common in fluids that are highly electrically conductive and carry strong currents. We determine the effect of stable stratification on the tearing instability under the Boussinesq approximation. Our…

Fluid Dynamics · Physics 2024-11-20 Scott J. Hopper , Toby S. Wood , Paul J. Bushby