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Related papers: Incipient bedforms in a bidirectional wind regime

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The proper orthogonal decomposition has been applied on a full-scale horizontal-axis wind turbine to shed light on the wake characteristics behind the wind turbine. In reality, the blade tip experiences high deflections even at the rated…

Reliably predicting the geomorphology and climate of planetary bodies requires knowledge of the dynamic threshold wind shear velocity below which saltation transport ceases. Here we measure this threshold in a wind tunnel for four…

Geophysics · Physics 2019-10-28 Wei Zhu , Xinghui Huo , Jie Zhang , Peng Wang , Thomas Pähtz , Ning Huang , Zhiguo He

We consider the three-dimensional instability of a layer of horizontal magnetic field in a polytropic atmosphere where, contrary to previous studies, the field lines in the initial state are not unidirectional. We show that if the twist is…

Solar and Stellar Astrophysics · Physics 2015-03-20 B. F. N. Favier , L. Jouve , W. Edmunds , L. J. Silvers , M. R. E. Proctor

We introduce order parameter models for describing the dynamics of sand ripple patterns under oscillatory flow. A crucial ingredient of these models is the mass transport between adjacent ripples, which we obtain from detailed numerical…

Condensed Matter · Physics 2009-10-31 Ken Haste Andersen , Marie-Line Chabanol , Martin van Hecke

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…

The saturation length of aeolian sand transport ($L_s$), characterizing the distance needed by wind-blown sand to adapt to changes in the wind shear, is essential for accurate modeling of the morphodynamics of Earth's sandy landscapes and…

Atmospheric and Oceanic Physics · Physics 2015-08-19 Thomas Pähtz , Amir Omeradžić , Marcus V. Carneiro , Nuno A. M. Araújo , Hans J. Herrmann

The instability and nonlinear evolution of directional ocean waves is investigated numerically by means of simulations of the governing kinetic equation for narrow-band surface waves. Our simulation results reveal the onset of the…

Fluid Dynamics · Physics 2015-05-14 Bengt Eliasson , Padma K. Shukla

Motion in a one-dimensional (1D) microfluidic array is simulated. Water droplets, dragged by flowing oil, are arranged in a single row, and due to their hydrodynamic interactions spacing between these droplets oscillates with a wave-like…

Fluid Dynamics · Physics 2015-06-05 Bin Liu , J. Goree , Yan Feng

We report on the motion of a spinning sleeping top on an inclined plane. Below a critical inclination angle the sleeping tops are force free. The trajectory of a sleeping top on weakly inclined planes in the adiabatic limit is invariant of…

Classical Physics · Physics 2021-11-24 Sven Barthmann , Thomas M. Fischer

A magnetic disc wind is an important mechanism that may be responsible for driving accretion and structure formation in protoplanetary discs. Recent numerical simulations have shown that these winds can take either the traditional…

Earth and Planetary Astrophysics · Physics 2020-08-19 Philip Kwong Ching Leung , Gordon I. Ogilvie

The main objective of this article is to derive a mathematical theory associated with the nonlinear stability and dynamic transitions of the basic shear flows associated with baroclinic instability, which plays a fundamental role in the…

Atmospheric and Oceanic Physics · Physics 2017-05-24 Ming Cai , Marco Hernandez , KiahWah Ong , Shouhong Wang

Ripples are the most fundamental and ubiquitous aeolian bedforms formed on sandy surfaces, but their small size and fast response times make them inherently difficult to measure. However, these attributes also make ripples excellent flow…

The water entry at high horizontal speed of double-curvature specimens, reproducing the rear part of the fuselage that first gets in contact with the water during aircraft ditching, is investigated experimentally. Three shapes are analysed,…

Fluid Dynamics · Physics 2025-09-03 Emanuele Spinosa , Silvano Grizzi , Alessandro Iafrati

Coastal dune management often alters crest and lee geometry, yet quantifying the transport impact of small shape changes is difficult without heavy models. This paper presents a streamlined, field-anchored CFD workflow (AirSketcher) that…

Fluid Dynamics · Physics 2025-09-24 Wichai Pattanapol , Kanisorn Thanutwutthigorn , Tipaporn Homdee

In this work we study the fingering double diffusive convection, namely the buoyancy-driven convection flow within a fluid layer experiencing an unstable salinity gradient and a stable thermal gradient. Especially, we investigate the…

Fluid Dynamics · Physics 2021-12-21 Junyi Li , Yantao Yang

We report an experimental study of a binary sand bed under an oscillating water flow. The formation and evolution of ripples is observed. The appearance of a granular segregation is shown to strongly depend on the sand bed preparation. The…

Soft Condensed Matter · Physics 2007-05-23 G. Rousseaux , H. Caps , J. -E. Wesfreid

Spontaneous growth of long-wavelength deformations is a defining feature of active fluids with orientational order. We investigate the effect of biaxial rectangular confinement on the instability of initially shear-aligned 3D isotropic…

Soft Condensed Matter · Physics 2021-01-04 Pooja Chandrakar , Minu Varghese , S. Ali Aghvami , Aparna Baskaran , Zvonimir Dogic , Guillaume Duclos

Confined granular fluids, placed in a shallow box that is vibrated vertically, can achieve homogeneous stationary states thanks to energy injection mechanisms that take place throughout the system. These states can be stable even at high…

Soft Condensed Matter · Physics 2015-06-12 Ricardo Brito , Dino Risso , Rodrigo Soto

Magnetic buoyancy instability plays an important role in the evolution of astrophysical magnetic fields. Here we revisit the problem introduced by \citet{Gilman_1970} of the short wavelength linear stability of a plane layer of compressible…

Solar and Stellar Astrophysics · Physics 2015-06-15 K. A. Mizerski , C. R. Davies , D. W. Hughes

This paper focuses on the stability analysis of a formation shape displayed by a team of mobile robots that uses heterogeneous sensing mechanism. Depending on the convenience and reliability of the local information, each robot utilizes the…

Systems and Control · Electrical Eng. & Systems 2020-10-22 Nelson P. K. Chan , Bayu Jayawardhana , Hector Garcia de Marina