In this paper, the divergent instability and coupled flutter characteristics of axially moving beams made functionally graded materials (FGM) are studied using interpolation matrix method. The material property beam is designed to change smoothly continuously along thickness direction. considering Euler-Bernoulli theory, Hamilton’s principle used derive differential equation transverse vibratio...

The somewhat counter-intuitive effect of how stratification destabilizes shear flows is reexamined, in what we believe to be the simplest example, in terms of action-at-a-distance interaction between ‘buoyancy-vorticity gravity wave kernels’. The setup consists of an infinite uniform shear Couette flow in which the Rayleigh-Fjortoft necessary conditions for shear flow instability are not satisf...

This work is devoted to the characterization and modeling of surprising stable states appearing in air-conveying soft tubes. A tube differs from a flexible by its very thin walls which allows it fold with sharp angle. When upper end fixed an air pump while bottom left free, system exhibits divergence instability develops under form “zig-zag” shapes constituted three roughly straight segments. W...

A non-parallel analysis of time-oscillatory instability of conical jets reveals important features not found in prior studies. Flow deceleration significantly enhances the shearlayer instability for both swirl-free and swirling jets. In swirl-free jets, flow deceleration causes the axisymmetric instability (absent in the parallel approximation). The critical Reynolds number Rea for this instabi...

The ensemble Kalman filter and ensemble square root filters are data assimilation methods used to combine high-dimensional, nonlinear dynamical models with observed data. Ensemble methods are indispensable tools in science and engineering and have enjoyed great success in geophysical sciences, because they allow for computationally cheap low-ensemble-state approximation for extremely high-dimen...

In this paper, we consider an exactly divergence-free scheme to solve the magnetic induction equations. This problem is motivated by the numerical simulations of ideal magnetohydrodynamic (MHD) equations, a nonlinear hyperbolic system with a divergence-free condition on the magnetic field. Computational methods without satisfying such condition may lead to numerical instability. One class of me...

The thermal fluctuation level of the Weibel instability is recalculated. It is shown that the divergence of the fluctuations at long wavelengths, i.e. the Weibel infrared catastrophe, never occurs. At large wavelengths the thermal fluctuation level is terminated by the presence of even the smallest available stable thermal anisotropy. Weibel fields penetrate only one skin depth into the plasma....

We consider a possible ways of the dynamics homogeneous and isotropic space described by FLRW metric in framework cubic f(R) gravity absence matter. This article points an method for limiting parameters extended models. propose develop models based on metrics various model simplest example. The influence initial conditions further are discussed. can be limited 1) slow growth space, 2) instabili...

Neonatal mortality is increasingly concentrated globally in situations of conflict and political instability. In 1991, countries with high levels of political instability accounted for approximately 10% of all neonatal deaths worldwide; in 2013, this figure had grown to 31%. This has generated a "grand divergence" between those countries showing progress in neonatal mortality reduction compared...