Publications associées à Transport d'Ekman

Reducing transport via extreme flux-surface triangularity

Based on a gyrokinetic analysis of and extrapolation from TCV discharges with large negative and positive triangularity delta, the potential of extreme | delta | in reducing turbulent transport is assessed. Linearly, both positive and negative delta can ex ...

IOP Publishing Ltd2024

Unraveling submesoscale processes associated with meso- and basin-scale gyres in Lake Geneva

Seyed Mahmood Hamze Ziabari

In large lakes, basin-scale gyres and submesoscale eddies, i.e., rotating coherent water masses, play a key role in spreading biochemical materials and energy throughout the basin, thereby significantly impacting water quality. Due to their transient and s ...

EPFL2023

Snow transport in extreme environments: from small to large scale modeling

Daniela Brito Melo

The cold regions on Earth, such as the polar and high mountain regions, are snow covered for at least a part of the year. These snow-covered surfaces are highly dynamic, particularly under the influence of strong winds. The aeolian or wind-driven transport ...

EPFL2023

Basin-scale gyres and mesoscale eddies in large lakes: A novel procedure for their detection and characterization, assessed in Lake Geneva

David Andrew Barry, Ulrich Lemmin, Seyed Mahmood Hamze Ziabari, Frédéric Charles Soulignac, Mehrshad Foroughan

In large lakes subject to the Coriolis force, basin-scale gyres and mesoscale eddies, i.e. rotating coherent water masses, play a key role in spreading biochemical materials and energy throughout the lake. In order to assess the spatial and temporal extent ...

2022

Dynamics of wind-induced coastal upwelling and interbasin exchange in Lake Geneva during winter: Implications for deepwater renewal

Rafael Sebastian Reiss

Water quality in lakes is closely linked to hydrodynamics and often dominated by stratification, limiting the exchange between the epi- and hypolimnion. Thus, the vertical redistribution of biogeochemical tracers such as dissolved oxygen and nutrients by c ...

EPFL2021

Wintertime Coastal Upwelling in Lake Geneva: An Efficient Transport Process for Deepwater Renewal in a Large, Deep Lake

David Andrew Barry, Ulrich Lemmin, Andrea Cimatoribus, Rafael Sebastian Reiss

Combining field measurements, 3‐D numerical modeling, and Lagrangian particle tracking, we investigated wind‐driven, Ekman‐type coastal upwelling during the weakly stratified winter period 2017/2018 in Lake Geneva, Western Europe's largest lake (max. depth ...

2020

Gyre formation in open and deep lacustrine embayments: The example of Lake Geneva, Switzerland

David Andrew Barry, Alfred Johny Wüest, Ulrich Lemmin, Damien Bouffard, Amir Mehdi Razmi, Robert Eduard Uittenbogaard

Numerical simulations were carried out to investigate gyres within open lacustrine embayments subjected to parallel-to-shore currents. In such embayments, gyre formation occurs due to flow separation at the embayment’s upstream edge. High momentum fluid fr ...

Springer Verlag2017

Buoyant Turbulent Kinetic Energy Production in Steep-Slope Katabatic Flow

Marc Parlange, Chad Higgins, Holly Jayne Oldroyd, Eric Richard Pardyjak

We develop several critical concepts that should be considered when interpreting, modelling and designing future experiments for flows over sloping terrain. Vertical buoyancy fluxes in katabatic flows can be positive and a source of turbulent kinetic energ ...

Springer Verlag2016

Drivers of deep-water renewal events observed over 13 years in the South Basin of Lake Baikal

Alfred Johny Wüest, Martin Schmid

Lake Baikal, with a depth of 1637 m, is characterized by deep-water intrusions that bridge the near-surface layer to the hypolimnion. These episodic events transfer heat and oxygen over large vertical scales and maintain the permanent temperature stratifie ...

Amer Geophysical Union2015

Stratification, mixing and transport processes in Lake Kivu

Alfred Johny Wüest, Martin Schmid

This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top â ¼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ...

Springer2012

Nutrient cycling in Lake Kivu

Alfred Johny Wüest, Natacha Tofield-Pasche, Martin Schmid

This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top ∼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ∼ ...

Springer2012

Intermittent oxygen flux from the interior into the bottom boundary of lakes as observed by eddy correlation

Alfred Johny Wüest, Bernhard Wehrli

Turbulent oxygen transport from the overlying stratified water column into the bottom boundary layer (BBL) on the slope of a medium-sized lake was investigated using the eddy correlation (EC) technique. The seicheinduced oscillatory flow of the BBL, with a ...

American Society of Limnology and Oceanography2008

An experimental study of coherent structures, secondary currents and surface boils and their interrelation in open-channel flow

Ismail Albayrak

River and open-channel flows are free surface boundary layer flows with complex 3D, large-scale, turbulent structures. The study of 2D and 3D large-scale turbulent flow structures is a great challenge for physicists, mathematicians and engineers from such ...

EPFL2008

Lake Baikal deepwater renewal mystery solved

Alfred Johny Wüest, Martin Schmid

Deepwater renewal by intrusions and turbulent diffusion in Lake Baikal is very effective despite the enormous depth of up to 1642 m and the permanently stable stratification below similar to 300 m depth. Temperature time series recorded at the bottom of a ...

Amer Geophysical Union2008

Cold intrusions in Lake Baikal: Direct observational evidence for deep-water renewal

Alfred Johny Wüest

We studied cold, deep-water intrusions in the South Basin of Lake Baikal on the basis of 2 yr of data (December 1995-November 1997) from near-bottom and near-surface thermistor strings, monthly conductivity-temperature-depth (CTD) profiles, and a near-bott ...

American Society of Limnology and Oceanography2005

Highly loaded compressor with boundary layer suction

Klaus Hubrich

An experimental and numerical investigation of boundary layer suction (BLS) on a transonic compressor blade has been conducted. The objective of the present work is to identify the possible benefit of boundary layer suction via a slot in the region of the ...

EPFL2005