Stability analysis of maglev elastic vehicle-guideway-coupled system

2011 ◽  
Author(s):  
Yu Tian ◽  
Longhua She
Keyword(s):  
Stability Analysis ◽  
Coupled System

Modulational instability in a biexciton molecular chain with saturable nonlinearity effects

2016 ◽  
Vol 30 (01) ◽  
pp. 1550244
Author(s):  
Issa Sali ◽  
C. B. Tabi ◽  
H. P. Ekobena ◽  
T. C. Kofané
Keyword(s):  
Stability Analysis ◽  
Numerical Simulations ◽  
Linear Stability Analysis ◽  
Adiabatic Approximation ◽  
Continuous Wave ◽  
Modulational Instability ◽  
Coupled System ◽  
Molecular Chain ◽  
Saturable Nonlinearity ◽  
Wave Solutions

In this paper, we study the modulational instability (MI) in a biexciton molecular chain taking into account the saturable nonlinearity effects (SNE). Under the adiabatic approximation, the biexciton system is reduced to two coupled nonlinear Schrödinger equations. We perform the linear stability analysis of continuous wave solutions of the coupled system. This analysis reveals that the MI gain is deeply influenced by the SNE. Indeed, the gain spectrum decreases when increasing the saturable nonlinearity parameters. The numerical simulations reveal that the system exhibits incoherent periodic array of patterns and we also observe train of pulses due to the SNE.

Stability analysis of mutualistic-parasitic coupled system

2012 ◽  
Vol 32 (21) ◽  
pp. 6848-6855
Author(s):  
高磊 GAO Lei ◽  
杨燕 YANG Yan ◽  
贺军州 HE Junzhou ◽  
王亚强 WANG Yaqiang ◽  
刘奇龙 LIU Qilong ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Coupled System

Stability analysis of Cu–H2O nanofluid over a curved stretching–shrinking sheet: existence of dual solutions

2019 ◽  
Vol 97 (8) ◽  
pp. 911-922 ◽  
Author(s):  
Usama ◽  
S. Nadeem ◽  
A.U. Khan
Keyword(s):  
Stability Analysis ◽  
Volume Fraction ◽  
Reverse Flow ◽  
Velocity Slip ◽  
Coupled System ◽  
Dual Solutions ◽  
Shrinking Sheet ◽  
Flow Situation ◽  
The Stability ◽  
Parameter Values

The effect of mass suction with temperature jump and velocity slip of viscous, unsteady nanofluid flow past a curved shrinking–stretching surface is analyzed in this work. Copper (Cu) and water are considered nanoparticles and base fluids, respectively. The complicated coupled system of differential equations is converted into non-dimensional form with some suitable similarity variables. The solution of the nonlinear problem is produced by use of numerical scheme available in the form of bvp4c package in MATLAB. In the case of shrinking towards the surface, a reverse flow situation is also developed and requires careful selection of solution by examining the stability of the solution. Detailed stability analysis is done and critical values are determined for the possible existence of dual solutions. Variation in parameters is analyzed by plotting graphs and tables. The numerical values are also calculated for the reduced Nusselt number and skin friction due to variation in values of different flow parameters. Results have shown that for the curved shrinking surfaces, one should expect multiple solutions for a set of parameter values such as mass suction, curvature, nanoparticles volume fraction, and unsteadiness.

Boundary Stabilization of Parachute Dams in Contact With Fluid

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Ali Najafi ◽  
Mohammad Eghtesad ◽  
Farhang Daneshmand ◽  
Amir Lotfazar
Keyword(s):  
Stability Analysis ◽  
Lyapunov Functional ◽  
Control Method ◽  
Nonlinear Partial Differential Equations ◽  
Coupled System ◽  
Control Force ◽  
Boundary Stabilization ◽  
Boundary Feedback ◽  
Boundary Control Method ◽  
The Stability

The boundary stabilization of a coupled fluid-structure system consisting of a vibrating parachute dam in contact with a fluid is studied in this paper. The parachute dam dynamics is presented by nonlinear partial differential equations. The fluid is assumed to be Newtonian, barotropic, and compressible. For the stability analysis of the coupled system, the boundary control method is used; a boundary feedback is constructed to stabilize the vibrations of the dam and the fluid simultaneously. The control force consists of the feedback from dam tension at its end. Moreover, the exponential stabilization of the parachute dam is achieved using a Lyapunov functional and boundary feedback.

scholarly journals Global linear stability analysis of the wake and path of buoyancy-driven disks and thin cylinders

2014 ◽  
Vol 740 ◽  
pp. 278-311 ◽  
Author(s):  
Joël Tchoufag ◽  
David Fabre ◽  
Jacques Magnaudet
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Stokes Equations ◽  
Coupled System ◽  
The Body ◽  
Navier Stokes ◽  
Fluid Inertia ◽  
Stability Diagrams ◽  
Wake Instability ◽  
The Stability

AbstractThe stability of the vertical path of a gravity- or buoyancy-driven disk of arbitrary thickness falling or rising in a viscous fluid, recently studied through direct numerical simulation by Auguste, Magnaudet & Fabre (J. Fluid Mech., vol. 719, 2013, pp. 388–405), is investigated numerically in the framework of global linear stability. The disk is allowed to translate and rotate arbitrarily and the stability analysis is carried out on the fully coupled system obtained by linearizing the Navier–Stokes equations for the fluid and Newton’s equations for the body. Three disks with different diameter-to-thickness ratios are considered: one is assumed to be infinitely thin, the other two are selected as archetypes of thin and thick cylindrical bodies, respectively. The analysis spans the whole range of body-to-fluid inertia ratios and considers Reynolds numbers (based on the fall/rise velocity and body diameter) up to $350$. It reveals that four unstable modes with an azimuthal wavenumber $m=\pm 1$ exist in each case. Three of these modes result from a Hopf bifurcation while the fourth is associated with a stationary bifurcation. Varying the body-to-fluid inertia ratio yields rich and complex stability diagrams with several branch crossings resulting in frequency jumps; destabilization/restabilization sequences are also found to take place in some subdomains. The spatial structure of the unstable modes is also examined. Analyzing differences between their real and imaginary parts (which virtually correspond to two different instants of time in the dynamics of a given mode) allows us to assess qualitatively the strength of the mutual coupling between the body and fluid. Qualitative and quantitative differences between present predictions and known results for wake instability past a fixed disk enlighten the fact that the first non-vertical regimes generally result from an intrinsic coupling between the body and fluid and not merely from the instability of the sole wake.

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