Concept

Golden ratio

Related publications (77)

Physical insights from the aspect ratio dependence of turbulence in negative triangularity plasmas

In this work, we study the impact of aspect ratio A = R 0 / r (the ratio of major radius R 0 to minor radius r) on the confinement benefits of negative triangularity (NT) plasma shaping. We use high-fidelity flux tube gyrokinetic GENE simulations and consi ...

Iop Publishing Ltd2024

Re-design of EU DEMO with a low aspect ratio

Hartmut Zohm

The design point that had been chosen for EU DEMO in 2016 is reviewed here and a modification is proposed with a lower aspect ratio. Previously the same aspect ratio, A, was chosen for EU DEMO as in major tokamak experiments including ITER (A = 3.1), and, ...

2024

Numerical study on the scale effect of tip vortex cavitation induced by incoming velocities and scale ratios

Mohamed Farhat, Huaiyu Cheng, Mohan Xu

Large eddy simulations of tip vortex cavitation (TVC) around an elliptical hydrofoil is performed to study its scale effect. A satisfying agreement is obtained between the numerical and experimental data. It indicates that the scale effect of TVC is remark ...

PERGAMON-ELSEVIER SCIENCE LTD2023

From thin plates to Ahmed bodies: linear and weakly nonlinear stability of rectangular prisms

Edouard Boujo, Giuseppe Antonio Zampogna

We study the stability of laminar wakes past three-dimensional rectangular prisms. The width-to-height ratio is set to W/H = 1.2, while the length-to-height ratio 1/6 < L/H < 3 covers a wide range of geometries from thin plates to elongated Ahmed bodies. F ...

CAMBRIDGE UNIV PRESS2023

Theory-Guided Enhancement of CO2 Reduction to Ethanol on Ag-Cu Tandem Catalysts via Particle-Size Effects

Raffaella Buonsanti, James Richard Pankhurst, Pranit Srinivas Iyengar

In the CO2 reduction reaction, the design of electrocatalysts that selectively promote alcohols over hydrocarbons (e.g., ethanol over ethylene) hinges on the understanding of the pathways and specific sites that form alcohols. Herein, theoretical considera ...

AMER CHEMICAL SOC2021

Effects of spanwise confinement on stratified shear instabilities

François Gallaire, Yves-Marie François Ducimetière

We consider the influence of transverse confinement on the instability properties of velocity and density distributions reminiscent of those pertaining to exchange flows in stratified inclined ducts, such as the recent experiment of Lefauve et al. [J. Flui ...

2021

Extremal Eigenvalues Of The Dirichlet Biharmonic Operator On Rectangles

We study the behaviour of extremal eigenvalues of the Dirichlet biharmonic operator over rectangles with a given fixed area. We begin by proving that the principal eigenvalue is minimal for a rectangle for which the ratio between the longest and the shorte ...

2020

Shaping effects on scrape-off layer plasma turbulence: A rigorous validation of three-dimensional simulations against TCV measurements

Paolo Ricci, Fabio Riva, Cedric Kar-Wai Tsui

The effect of plasma shaping on scrape-off layer (SOL) plasma turbulence is investigated through a rigorous validation exercise. Two- and three-dimensional simulations of the SOL plasma dynamics in three TCV limited discharges are carried out with the GBS ...

2020

Structured nanoscale metallic glass fibres with extreme aspect ratios

Stéphanie Lacour, Grégoire Courtine, Vasiliki Tileli, Fabien Sorin, Jordan Squair, Nicholas David James, Wei Yan, Yunpeng Qu, Dang Tùng Nguyen, Güven Kurtuldu, Reinis Ignatans, Giuseppe Schiavone, Inès Richard

Micro- and nanoscale metallic glasses offer exciting opportunities for both fundamental research and applications in healthcare, micro-engineering, optics and electronics. The scientific and technological challenges associated with the fabrication and util ...

NATURE PUBLISHING GROUP2020

Singular global components and frequency shift of the geodesic acoustic continuum modes in shaped tokamaks

Jonathan Graves

Within the ideal magnetohydrodynamic (MHD) model, the geodesic acoustic modes (GAMs) in tokamaks derived by Winsor et al (1968 Phys. Fluids 11 2448) belong to the continuous spectrum, characterised by unbounded non-square integrable eigenfunctions (delta f ...

2019

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