Robert E. Ecke
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View article: The center for nonlinear studies: A personal history
The center for nonlinear studies: A personal history Open
The Center for Nonlinear Studies (CNLS) was an integral part of my scientific career starting as a Postdoctoral Fellow in 1983 up to my tenure as CNLS Director from 2004 to 2015. As such, I experienced a number of scientific phases of CNLS…
View article: THE RAYLEIGH-TAYLOR INSTABILITY IN SMALL ASPECT RATIO CONTAINERS
THE RAYLEIGH-TAYLOR INSTABILITY IN SMALL ASPECT RATIO CONTAINERS Open
We present experimental measurements of density and velocity obtained from the mixing zone of buoyancy driven turbulence initiated by the Rayleigh-Taylor instability in a small aspect ration chamber (a chamber who's vertical height is sign…
View article: Turbulent mixing and entrainment in a gravity current
Turbulent mixing and entrainment in a gravity current Open
We present an experimental study of the mixing processes in a gravity current. The turbulent transport of momentum and buoyancy can be described in a very direct and compact form by a Prandtl mixing length model: the turbulent vertical flu…
View article: Mixing lengths scaling in a gravity flow
Mixing lengths scaling in a gravity flow Open
We present an experimental study of the mixing processes in a gravity current. The turbulent transport of momentum and buoyancy can be described in a very direct and compact form by a Prandtl mixing length model [1]: the turbulent vertical…
View article: Patterns and instability of grannular flow
Patterns and instability of grannular flow Open
Dense granular flows are often observed to become unstable and form inhomogeneous structures in nature or industry. Although recently significant advances have been made in understanding simple flows, instabilities are often not understood…
View article: Heat transport measurements in turbulent rotating Rayleigh-Benard convection
Heat transport measurements in turbulent rotating Rayleigh-Benard convection Open
We present experimental heat transport measurements of turbulent Rayleigh-Benard convection with rotation about a vertical axis. The fluid, water with Prandtl number ({sigma}) about 6, was confined in a cell which had a square cross sectio…
View article: Wall modes and the transition to bulk convection in rotating Rayleigh-Bénard convection
Wall modes and the transition to bulk convection in rotating Rayleigh-Bénard convection Open
We investigate states of rapidly rotating Rayleigh-Bénard convection in a cylindrical cell over a range of Rayleigh number $3\times10^5\leq Ra \leq 5\times10^{9}$ and Ekman number $10^{-6} \leq Ek \leq 10^{-4}$ for Prandtl number $Pr = 0.8…
View article: Turbulent Rotating Rayleigh–Bénard Convection
Turbulent Rotating Rayleigh–Bénard Convection Open
Rotation with thermally induced buoyancy governs many astrophysical and geophysical processes in the atmosphere, ocean, sun, and Earth's liquid-metal outer core. Rotating Rayleigh–Bénard convection (RRBC) is an experimental system that has…
View article: Connecting wall modes and boundary zonal flows in rotating Rayleigh-Bénard convection
Connecting wall modes and boundary zonal flows in rotating Rayleigh-Bénard convection Open
Using direct numerical simulations, we study rotating Rayleigh-Bénard convection in a cylindrical cell for a broad range of Rayleigh, Ekman, and Prandtl numbers from the onset of wall modes to the geostrophic regime, an extremely important…
View article: Where have all the wall modes gone? Rethinking rotating Rayleigh-B\'enard convection in the geostrophic regime
Where have all the wall modes gone? Rethinking rotating Rayleigh-B\'enard convection in the geostrophic regime Open
Using direct numerical simulations, we study rotating Rayleigh-Benard convection in a cylindrical cell for a broad range of Rayleigh, Ekman, and Prandtl numbers from the onset of wall modes to the geostrophic regime, an extremely important…
View article: Boundary zonal flows in rapidly rotating turbulent thermal convection
Boundary zonal flows in rapidly rotating turbulent thermal convection Open
View article: Thermal kinetics of free volume in porous spin-on dielectrics: Exploring the network- and pore-properties
Thermal kinetics of free volume in porous spin-on dielectrics: Exploring the network- and pore-properties Open
Art. 110457, 10 S.
View article: Boundary Zonal Flow in Rotating Turbulent Rayleigh-Bénard Convection
Boundary Zonal Flow in Rotating Turbulent Rayleigh-Bénard Convection Open
For rapidly rotating turbulent Rayleigh-Bénard convection in a slender cylindrical cell, experiments and direct numerical simulations reveal a boundary zonal flow (BZF) that replaces the classical large-scale circulation. The BZF is locate…
View article: Slow Dynamics and Strength Recovery in Unconsolidated Granular Earth Materials: A Mechanistic Theory
Slow Dynamics and Strength Recovery in Unconsolidated Granular Earth Materials: A Mechanistic Theory Open
Rock materials often display long‐time relaxation, commonly termed aging or “slow dynamics,” after the cessation of acoustic perturbations. In this paper, we focus on unconsolidated rock materials and propose to explain such nonlinear rela…
View article: From 2D to 3D in fluid turbulence: unexpected critical transitions
From 2D to 3D in fluid turbulence: unexpected critical transitions Open
How do the laws of physics change with changes in spatial dimension? Maybe not at all in some cases, but in important cases, the changes are dramatic. Fluid turbulence – the fluctuating, intermittent and many-degree-of-freedom state of a h…
View article: Stability, intermittency and universal Thorpe length distribution in a laboratory turbulent stratified shear flow
Stability, intermittency and universal Thorpe length distribution in a laboratory turbulent stratified shear flow Open
Stratified shear flows occur in many geophysical contexts, from oceanic overflows and river estuaries to wind-driven thermocline layers. We explore a turbulent wall-bounded shear flow of lighter miscible fluid into a quiescent fluid of hig…
View article: Simulating stick‐slip failure in a sheared granular layer using a physics‐based constitutive model
Simulating stick‐slip failure in a sheared granular layer using a physics‐based constitutive model Open
We model laboratory earthquakes in a biaxial shear apparatus using the Shear‐Transformation‐Zone (STZ) theory of dense granular flow. The theory is based on the observation that slip events in a granular layer are attributed to grain rearr…
View article: Plume dynamics in Hele-Shaw porous media convection
Plume dynamics in Hele-Shaw porous media convection Open
Mass transport in multi-species porous media is through molecular diffusion and plume dynamics. Predicting the rate of mass transport has application in determining the efficiency of the storage and sequestration of carbon dioxide. We stud…
View article: A filtering approach for analyzing turbulent stratified shear flows
A filtering approach for analyzing turbulent stratified shear flows Open
A filtering approach for analyzing turbulent stratified shear flows Robert E. Ecke 1 and Philippe Odier 2 Condensed Matter and Magnetic Science and CNLS, Los Alamos National Laboratory, Los Alamos, NM USA: [email protected] Laboratoire de Phys…
View article: Lagrangian statistics in weakly forced two-dimensional turbulence
Lagrangian statistics in weakly forced two-dimensional turbulence Open
Measurements of Lagrangian single-point and multiple-point statistics in a quasi-two-dimensional stratified layer system are reported. The system consists of a layer of salt water over an immiscible layer of Fluorinert and is forced electr…
View article: Stick-slip behavior in a continuum-granular experiment
Stick-slip behavior in a continuum-granular experiment Open
We report moment distribution results from a laboratory experiment, similar in character to an isolated strike-slip earthquake fault, consisting of sheared elastic plates separated by a narrow gap filled with a two-dimensional granular med…
View article: Chaos, patterns, coherent structures, and turbulence: Reflections on nonlinear science
Chaos, patterns, coherent structures, and turbulence: Reflections on nonlinear science Open
The paradigms of nonlinear science were succinctly articulated over 25 years ago as deterministic chaos, pattern formation, coherent structures, and adaptation/evolution/learning. For chaos, the main unifying concept was universal routes t…
View article: Optimum Laser Exposure for Setting Exchange Bias in Spin Valve Sensors
Optimum Laser Exposure for Setting Exchange Bias in Spin Valve Sensors Open
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