scholarly journals An analytical connection between temporal and spatio-temporal growth rates in linear stability analysis

Author(s):  
Lennon Ó Náraigh ◽  
Peter D. M. Spelt

We derive an exact formula for the complex frequency in spatio-temporal stability analysis that is valid for arbitrary complex wavenumbers. The usefulness of the formula lies in the fact that it depends only on purely temporal quantities, which are easily calculated. We apply the formula in two model dispersion relations: the linearized complex Ginzburg–Landau equation, and a model of wake instability. In the first case, a quadratic truncation of the exact formula applies; in the second, the same quadratic truncation yields an estimate of the parameter values at which the transition to absolute instability occurs; the error in the estimate decreases upon increasing the order of the truncation. We outline ways in which the formula can be used to characterize stability results obtained from purely numerical calculations, and point to a further application in global stability analyses.

Author(s):  
S Boccaletti ◽  
J Bragard

We discuss some issues related with the process of controlling space–time chaotic states in the one-dimensional complex Ginzburg–Landau equation. We address the problem of gathering control over turbulent regimes with the use of only a limited number of controllers, each one of them implementing, in parallel, a local control technique for restoring an unstable plane-wave solution. We show that the system extension does not influence the density of controllers needed in order to achieve control.


Author(s):  
Laurent Nana ◽  
Alexander B. Ezersky ◽  
Innocent Mutabazi

Experiments in extended systems, such as the counter-rotating Couette–Taylor flow or the Taylor–Dean flow system, have shown that patterns with vanishing amplitude may exhibit periodic spatio-temporal defects for some range of control parameters. These observations could not be interpreted by the complex Ginzburg–Landau equation (CGLE) with periodic boundary conditions. We have investigated the one-dimensional CGLE with homogeneous boundary conditions. We found that, in the ‘Benjamin–Feir stable’ region, the basic wave train bifurcates to state with periodic spatio-temporal defects. The numerical results match the observations quite well. We have built a new state diagram in the parameter plane spanned by the criticality (or equivalently the linear group velocity) and the nonlinear frequency detuning.


2015 ◽  
Vol 360 ◽  
pp. 341-348 ◽  
Author(s):  
Pring Wong ◽  
Li-Hui Pang ◽  
Long-Gang Huang ◽  
Yan-Qing Li ◽  
Ming Lei ◽  
...  

2018 ◽  
Vol 30 (11) ◽  
pp. 114103 ◽  
Author(s):  
Jacob Sebastian ◽  
Benjamin Emerson ◽  
J. O’Connor ◽  
Tim Lieuwen

1997 ◽  
Vol 07 (07) ◽  
pp. 1539-1554 ◽  
Author(s):  
M. Ipsen ◽  
F. Hynne ◽  
P. G. Sørensen

The paper discusses the use of amplitude equations to describe the spatio-temporal dynamics of a chemical reaction–diffusion system based on an Oregonator model of the Belousov–Zhabotinsky reaction. Sufficiently close to a supercritical Hopf bifurcation the reaction–diffusion equation can be approximated by a complex Ginzburg–Landau equation with parameters determined by the original equation at the point of operation considered. We illustrate the validity of this reduction by comparing numerical spiral wave solutions to the Oregonator reaction–diffusion equation with the corresponding solutions to the complex Ginzburg–Landau equation at finite distances from the bifurcation point. We also compare the solutions at a bifurcation point where the systems develop spatio-temporal chaos. We show that the complex Ginzburg–Landau equation represents the dynamical behavior of the reaction–diffusion equation remarkably well, sufficiently far from the bifurcation point for experimental applications to be feasible.


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