In the present study, double-diffusive oscillatory convection of binary mixture, 3He–4He, in porous medium heated from below and cooled above was investigated with stress-free boundary conditions. The Darcy model employed governing system perturbed equations. An attempt made, for first time, to solve these equations by using nonlinear analysis-based truncated Fourier series. influence Rayleigh ...

A one-step reduced chemical-kinetic mechanism describing near-critical hydrogen combustion, recently derived by assuming that all chemical intermediates maintain steady state, is used to investigate numerically the pulsating dynamics of fuel-rich hydrogen-air flames. The computations, considering pressures up 20 atmospheres, address flame evolution for increasing values equivalence ratio ϕ , a ...

Motivated by experimental observations of exotic free surface standing wave patterns in the two-frequency Faraday experiment, we investigate the role of normal form symmetries in the associated pattern-selection problem. With forcing frequency components in ratio m/n, where m and n are coprime integers that are not both odd, there is the possibility that both harmonic waves and subharmonic wave...

A numerical characterization based on experimental data of the spouting regime in a two-dimensional fluidized bed is presented. The aspect ratio of the bed allowed for good visualization of the spouting and solids circulation as the spouting jet gas velocity was varied to highlight the visited bifurcation sequence. Digital video sequences were recorded and then preprocessed for numerical analys...

We evaluate the effect of the aspect ratio, i.e., the distance between the propellers H divided by the diameter D, on the slow dynamics of a von Kármán swirling flow driven by two propellers in a closed cylinder. We use a cell with a fixed diameter D but where the distance between the propellers can be turned continuously and where the inertia from the propellers can also be changed using diffe...

The nonlinear dynamics of Taylor-Couette flow in a small aspect ratio annulus (where the length of the cylinders is half of the annular gap between them) is investigated by numerically solving the full three-dimensional Navier-Stokes equations. The system is invariant to arbitrary rotations about the annulus axis and to a reflection about the annulus half-height, so that the symmetry group is S...

We investigate the bifurcation properties and pattern selection in Rayleigh-Bénard convecting binary mixtures for parameter combinations that are typical for colloidal fluids using the Galerkin method. In such fluids the typical Lewis numbers and separation ratios differ by orders of magnitude from the values found in molecular mixtures like alcohol/water. We study stationary rolls, square and ...

Recent studies in isolated cardiac tissue preparations have demonstrated the applicability of a one-dimensional difference equation model describing the global behavior of a driven nonpacemaker cell to the understanding of rate-dependent cardiac excitation. As a first approximation to providing an ionic basis to complex excitation patterns in cardiac cells, we have compared the predictions of t...

Biological oscillators coordinate individual cellular components so that they function coherently and collectively. They are typically composed of multiple feedback loops, and period mismatch is unavoidable in biological implementations. We investigated the advantageous effect of this period mismatch in terms of a synchronization response to external stimuli. Specifically, we considered two fun...