Article
Mechanics
S. F. Lewin, C. P. Caulfield
Summary: Motivated by the variation of local shear produced by internal waves in the ocean, this study investigates the effect of a time-dependent shear forcing on the evolution and mixing of turbulence produced by Kelvin-Helmholtz instability (KHI) through direct numerical simulations. The results demonstrate that turbulence produced by KHI with a decelerating shear mixes in a distinctly different way from the flow with constant background shear, with characteristics more in common with convectively driven flows.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Derek J. Grimes, Falk Feddersen
Summary: The study examines the stratified inner-shelf response to surf-zone-generated transient rip currents (TRC) and finds that the response is influenced by key dimensional parameters N-0 and d(s). TRC mixing increases background potential energy and available potential energy, driving inner-shelf mean circulation, while shoreward mixing by TRC forms a self-similar far-field intrusion.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
J. Labarbe, P. Le Gal, U. Harlander, S. Le Dizes, B. Favier
Summary: This paper presents a numerical analysis of the instability in horizontally sheared Poiseuille flow with vertical stratification. The study extends the previous work on the linear instability of this configuration and investigates nonlinear regimes through direct numerical simulations. The results show that the flow loses its vertical homogeneity through a secondary bifurcation and exhibits intermittent dynamics with bursting events and localized shear instabilities.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
M. Ryan Buchta, Jason Yalim, Bruno D. Welfert, Juan M. Lopez
Summary: The study investigates the flow characteristics of a Boussinesq fluid in a square container with inclined walls, including thermally stratified layers, wall boundary layers, and shear layers. The equilibrium is maintained through a balance of dissipation, heat flux, and induced flow. When the container undergoes vertical oscillations, the fluid response exhibits a modal cellular structure initially, transitioning to instabilities with increasing forcing amplitude.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
H. M. Yin, Q. Pan, K. W. Chow
Summary: Crossing sea states, where free surface waves with multiple spectral peaks propagate at oblique angles to each other, have been suggested as potential causes of rogue waves and maritime accidents. Theoretical models using coupled Schrodinger or Zakharov equations have been adopted, and extensions to layered and stratified fluids have been conducted. The results show that crossing patterns with multiple short waves enhance instability compared to single wave cases, and a cascading mechanism explains the analytical treatment beyond linear instability regime.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Mechanics
Philippe Guyenne, Adilbek Kairzhan, Catherine Sulem
Summary: This paper studies the water wave problem in a two-dimensional domain of infinite depth in the presence of non-zero constant vorticity. The effects of uniform shear flow on weakly nonlinear quasi-monochromatic surface gravity waves modulation are described. A Hamiltonian Dysthe equation is derived for the time evolution of the wave envelope using Hamiltonian transformation theory. The model is validated through numerical simulations and comparisons with related equations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Optics
Anastasiia Sheveleva, Ugo Andral, Bertrand Kibler, Pierre Colman, John M. Dudley, Christophe Finot
Summary: In this study, we overcome the challenges of observing ideal four-wave mixing dynamics and extend the effective propagation distance using programmable phase and amplitude shaping. The experimental results are in excellent agreement with numerical solutions, revealing the complete phase space topology.
Article
Physics, Multidisciplinary
Meital Geva, Lev Shemer
Summary: We validate a theory of wind wave evolution in time and space through experimentation in a laboratory wind-wave tank. The model accurately describes the development of the complex wave field from a smooth initial surface to a finite state. Incorporating the stochastic nature of wind waves, the model considers an ensemble of coexisting unstable harmonics that grow due to shear flow instability. The growth of the waves is initially limited by breaking, and then controlled by the duration of fetch-limited growth.
PHYSICAL REVIEW LETTERS
(2022)
Article
Mechanics
Jason Yalim, Bruno D. Welfert, Juan M. Lopez
Summary: The study examines the response to harmonic horizontal oscillations of a stably stratified fluid-filled two-dimensional square container as the forcing amplitude increases. At very small forcing amplitudes, the response flow is a synchronous periodic flow with piecewise-constant vorticity in regions delineated by the characteristics emanating from the corners of the container. Above a critical forcing amplitude, a sequence of pairs of other container modes are excited via triadic resonances with the second-harmonic-driven mode. The flows are computed using the Navier-Stokes-Boussinesq equations and the dynamics are analysed using Fourier techniques, providing a comprehensive understanding of the transition to internal wave turbulence.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Natanael Karjanto
Summary: The study focuses on a mathematical model of a perturbed stratified shear mean flow with eddy coefficients of turbulent viscosity, neglecting the influence of eddy coefficients of turbulent diffusivity. The model yields a modified TG equation with the same order as the classical, inviscid one. Under the assumption of slowly varying Brunt-Vaisala frequency and background horizontal velocity, geometric and physical optics approximations of the modified TG equation are discussed using the WKB method, investigating their behavior near singular values of a turning point and critical level.
Article
Mechanics
P. A. Allen, R. M. Dorrell, O. G. Harlen, R. E. Thomas, W. D. McCaffrey
Summary: This paper investigates the effects of density and viscosity stratification in the lock-exchange configuration. The results show that viscosity stratification can only be neglected when the viscosity ratio is small, and the initial turbidity current composition can enhance its self-sustaining or accelerating ability at intermediate viscosity ratios.
Article
Mechanics
Nguyen Ly, Matthias Ihme
Summary: Compressible mixing layer instabilities are important in various environmental and industrial applications. Previous studies have mainly focused on the thermodynamic regimes of ideal-gas or real-fluid single-species mixing layers. However, binary mixing layers at supercritical conditions, commonly encountered in fuel injection systems, introduce additional complexities due to the added compositional degree-of-freedom. The effect of variations in thermodynamic response functions across the Widom line on the stability of binary mixing layers remains poorly understood. This study aims to examine the coupling between hydrodynamic instability and real-fluid thermodynamics across the Widom line and its effects on the dynamics of binary mixing layers.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
H. M. Aravind, Thomas Dubos, Manikandan Mathur
Summary: This study investigates the stability of two-dimensional Kelvin-Helmholtz vortices using numerical simulations. The results show that different types of instabilities occur at the core and the edge of the vortices, and stratification strongly influences the instability at the vortex edge. The dependence of the dominant instability characteristics on the Richardson number is systematically studied. The local stability approach is able to predict the orientation of flow structures resulting from different instabilities, consistent with previous three-dimensional numerical simulations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Tianning Tang, Charlotte Moss, Samuel Draycott, Harry B. Bingham, Ton S. van den Bremer, Yan Li, Thomas A. A. Adcock
Summary: This study investigates the phenomenon of rogue waves in multidirectional waves and finds that the formation probability of rogue waves decreases in directional seas compared to unidirectional seas. However, for typical values of directional spreading in the ocean, there is still a significant enhancement to the number of rogue waves just beyond the top of a depth discontinuity.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Tianning Tang, Dylan Barratt, Harry B. Bingham, Ton S. van den Bremer, Thomas A. A. Adcock
Summary: This study investigates the impact of curtailing the wave spectrum when producing directional surface gravity waves in a wave tank or initializing numerical simulations of the ocean. The results show that curtailing the spectrum can lead to the generation of more extreme rogue waves through nonlinear physics, persisting over multiple periods. This suggests that sea states without equilibrium can produce an increased number of rogue waves and have an impact on predicted loads on offshore infrastructure.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Physics, Fluids & Plasmas
Maxime Brunet, Thierry Dauxois, Pierre-Philippe Cortet
PHYSICAL REVIEW FLUIDS
(2019)
Article
Meteorology & Atmospheric Sciences
Paige E. Martin, Brian K. Arbic, Andrew McC Hogg, Andrew E. Kiss, James R. Munroe, Jeffrey R. Blundell
JOURNAL OF CLIMATE
(2020)
Article
Mechanics
Geraldine Davis, Thierry Dauxois, Timothee Jamin, Sylvain Joubaud
JOURNAL OF FLUID MECHANICS
(2019)
Article
Physics, Multidisciplinary
Geraldine Davis, Timothee Jamin, Julie Deleuze, Sylvain Joubaud, Thierry Dauxois
PHYSICAL REVIEW LETTERS
(2020)
Article
Physics, Fluids & Plasmas
Pauline Husseini, Dheeraj Varma, Thierry Dauxois, Sylvain Joubaud, Philippe Odier, Manikandan Mathur
PHYSICAL REVIEW FLUIDS
(2020)
Article
Mechanics
Timothee Jamin, Takeshi Kataoka, Thierry Dauxois, T. R. Akylas
Summary: The study investigates the evolution of mean flow induced by a three-dimensional propagating internal gravity wave beam in a uniformly stratified fluid, revealing three distinct stages: resonant growth, saturation of streaming and onset of horizontal advection, and establishment of a quasi-steady state. The theoretical model proposed in this study, which extends previous work by accounting for horizontal advection and viscous diffusion effects, is in excellent agreement with experimental observations and numerical simulations.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
T. Dauxois, T. Peacock, P. Bauer, C. P. Caulfield, C. Cenedese, C. Gorle, G. Haller, G. N. Ivey, P. F. Linden, E. Meiburg, N. Pinardi, N. M. Vriend, A. W. Woods
Summary: Environmental fluid mechanics is essential for addressing natural, industrial, and societal challenges. A workshop was organized to gather leading figures in the field and discuss five subject areas for the scientific community, aiming to provide a resource for future research.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Mechanics
Yohei Onuki, Sylvain Joubaud, Thierry Dauxois
Summary: A new technique was developed to assess internal wave-driven mixing in the ocean through direct numerical simulations of stratified turbulence. The study found that the external wave can directly supply energy for turbulence and mixing, and the mixing coefficient tends to increase with the Fr number of the external wave. Disturbances in the model go through two stages, converting wave energy into turbulence energy and eventually dissipating it.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
S. Boury, I. Sibgatullin, E. Ermanyuk, N. Shmakova, P. Odier, S. Joubaud, L. R. M. Maas, T. Dauxois
Summary: This study investigates the nonlinear dynamics of an inertial wave attractor in an axisymmetric geometrical setting both experimentally and numerically. The results show the development of a slow two-dimensional manifold and various dynamic regimes, such as triadic resonance instability and inertial wave turbulence, confirming the experimental observation of a polygonal vortex cluster. The formation and long-term fate of these vortex clusters resulting from merging wave-like components of the vorticity field remain to be explored.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
B. R. Sutherland, Y. Ma, M. R. Flynn, D. Frank, P. F. Linden, D. Lemasquerier, M. Le Bars, C. Pacary, T. Jamin, T. Dauxois, S. Joubaud
Summary: Through laboratory experiments and numerical simulations, it was found that rotation does not directly affect buoyant plumes in a uniform density ambient fluid with a sufficiently large source Rossby number. However, on a time scale of half a rotation period, the plume becomes deflected and may even form tornadoes. The likelihood of tornado formation is higher in plumes with a 'lazy' nature, as it is a result of competing dynamics occurring on comparable time scales.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
Daniel Odens Mora, Eduardo Monsalve, Maxime Brunet, Thierry Dauxois, Pierre-Philippe Cortet
Summary: By theoretical analysis and numerical integration, we investigated the triadic resonance instability (TRI) of a plane inertial wave in a rotating fluid, showing that the maximum growth rate of the TRI is found for secondary waves that do not propagate in the same vertical plane as the primary wave. Experimental evidence confirms the three-dimensional nature of the TRI of a plane inertial wave, with wave vectors of secondary waves matching theoretical predictions based on the maximum growth rate criterion.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Physics, Fluids & Plasmas
Vazha Loladze, Thierry Dauxois, Ramaz Khomeriki, Stefano Ruffo
Article
Geosciences, Multidisciplinary
Andrew E. Kiss, Andrew McC Hogg, Nicholas Hannah, Fabio Boeira Dias, Gary B. Brassington, Matthew A. Chamberlain, Christopher Chapman, Peter Dobrohotoff, Catia M. Domingues, Earl R. Duran, Matthew H. England, Russell Fiedler, Stephen M. Griffies, Aidan Heerdegen, Petra Heil, Ryan M. Holmes, Andreas Klocker, Simon J. Marsland, Adele K. Morrison, James Munroe, Maxim Nikurashin, Peter R. Oke, Gabriela S. Pilo, Oceane Richet, Abhishek Savita, Paul Spence, Kial D. Stewart, Marshall L. Ward, Fanghua Wu, Xihan Zhang
GEOSCIENTIFIC MODEL DEVELOPMENT
(2020)
Article
Materials Science, Multidisciplinary
Sourav Biswas, Clemens B. Winkelmann, Herve Courtois, Thierry Dauxois, Hillol Biswas, Anjan K. Gupta
Article
Physics, Multidisciplinary
F. Staniscia, R. Bachelard, T. Dauxois, G. De Ninno
