The linear and nonlinear shear instability of a fluid sheet

1991 ◽  
Vol 3 (10) ◽  
pp. 2392-2400 ◽  
Author(s):  
R. H. Rangel ◽  
W. A. Sirignano
Keyword(s):  
Shear Instability ◽  
Linear And Nonlinear ◽  
Nonlinear Shear

Linear and Nonlinear Shear Rheology of a Marginally Entangled Ring Polymer

2016 ◽  
Vol 49 (4) ◽  
pp. 1444-1453 ◽  
Author(s):  
Zhi-Chao Yan ◽  
Salvatore Costanzo ◽  
Youncheol Jeong ◽  
Taihyun Chang ◽  
Dimitris Vlassopoulos
Keyword(s):  
Shear Rheology ◽  
Ring Polymer ◽  
Linear And Nonlinear ◽  
Nonlinear Shear

Solar Orbiter observations of magnetic Kelvin-Helmholtz waves in the solar wind

2021 ◽  
Author(s):  
Rungployphan Kieokaew ◽  
Benoit Lavraud ◽  
David Ruffolo ◽  
William Matthaeus ◽  
Yan Yang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Heliospheric Current Sheet ◽  
Shear Instability ◽  
Slow Solar Wind ◽  
Flow Shear ◽  
In Situ Observations ◽  
Set Up ◽  
Nonlinear Shear ◽  
Wind Source

<p>The Kelvin-Helmholtz instability (KHI) is a nonlinear shear-driven instability that develops at the interfaces between shear flows in plasmas. KHI is ubiquitous in plasmas and has been observed in situ at planetary interfaces and at the boundaries of coronal mass ejections in remote-sensing observations. KHI is also expected to develop at flow shear interfaces in the solar wind, but while it was hypothesized to play an important role in the mixing of plasmas and exciting solar wind fluctuations, its direct observation in the solar wind was still lacking. We report first in-situ observations of ongoing KHI in the solar wind using Solar Orbiter during its cruise phase. The KHI is found in a shear layer in the slow solar wind near the Heliospheric Current Sheet. We find that the observed conditions satisfy the KHI onset criterion from linear theory and the steepening of the shear boundary layer is consistent with the development of KH vortices. We further investigate the solar wind source of this event to understand the conditions that support KH growth. In addition, we set up a local MHD simulation using the empirical values to reproduce the observed KHI. This observed KHI in the solar wind provides robust evidence that shear instability develops in the solar wind, with obvious implications in the driving of solar wind fluctuations and turbulence. The reasons for the lack of previous such measurements are also discussed.</p>

Linear and Nonlinear Shear Moduli of Materials Associated with Heap Leach-Pad Mining

2017 ◽  
Author(s):  
A. K. Keene ◽  
H. Jaffal ◽  
K. H. Stokoe ◽  
C. S. El Mohtar ◽  
A. Reyes ◽  
...  
Keyword(s):  
Shear Moduli ◽  
Heap Leach ◽  
Linear And Nonlinear ◽  
Nonlinear Shear

Linear and nonlinear shear studies reveal supramolecular responses in supercooled monohydroxy alcohols with faint dielectric signatures

2019 ◽  
Vol 150 (10) ◽  
pp. 104501 ◽  
Author(s):  
S. Peter Bierwirth ◽  
Gabriel Honorio ◽  
Catalin Gainaru ◽  
Roland Böhmer
Keyword(s):  
Linear And Nonlinear ◽  
Nonlinear Shear

Linear and nonlinear shear flow behavior of monodisperse polyisoprene melts with a large range of molecular weights

2008 ◽  
Vol 52 (3) ◽  
pp. 801-835 ◽  
Author(s):  
Dietmar Auhl ◽  
Jorge Ramirez ◽  
Alexei E. Likhtman ◽  
Pierre Chambon ◽  
Christine Fernyhough
Keyword(s):  
Shear Flow ◽  
Large Range ◽  
Flow Behavior ◽  
Molecular Weights ◽  
Linear And Nonlinear ◽  
Nonlinear Shear

Weakly nonlinear shear waves

1998 ◽  
Vol 372 ◽  
pp. 71-91 ◽  
Author(s):  
FALK FEDDERSEN
Keyword(s):  
Shear Wave ◽  
Surf Zone ◽  
Second Harmonic ◽  
Shear Waves ◽  
Finite Amplitude ◽  
Shear Instability ◽  
Weakly Nonlinear ◽  
Wide Range ◽  
Alongshore Current ◽  
Nonlinear Shear

Alongshore propagating low-frequency O(0.01 Hz) waves related to the direction and intensity of the alongshore current were first observed in the surf zone by Oltman-Shay, Howd & Birkemeier (1989). Based on a linear stability analysis, Bowen & Holman (1989) demonstrated that a shear instability of the alongshore current gives rise to alongshore propagating shear (vorticity) waves. The fully nonlinear dynamics of finite-amplitude shear waves, investigated numerically by Allen, Newberger & Holman (1996), depend on α, the non-dimensional ratio of frictional to nonlinear terms, essentially an inverse Reynolds number. A wide range of shear wave environments are reported as a function of α, from equilibrated waves at larger α to fully turbulent flow at smaller α. When α is above the critical level αc, the system is stable. In this paper, a weakly nonlinear theory, applicable to α just below αc, is developed. The amplitude of the instability is governed by a complex Ginzburg–Landau equation. For the same beach slope and base-state alongshore current used in Allen et al. (1996), an equilibrated shear wave is found analytically. The finite-amplitude behaviour of the analytic shear wave, including a forced second-harmonic correction to the mean alongshore current, and amplitude dispersion, agree well with the numerical results of Allen et al. (1996). Limitations in their numerical model prevent the development of a side-band instability. The stability of the equilibrated shear wave is demonstrated analytically. The analytical results confirm that the Allen et al. (1996) model correctly reproduces many important features of weakly nonlinear shear waves.

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