Convection in binary fluid mixtures with modulated heating.

The response behavior of strongly nonlinear binary fluid convection to temporal modulation of the heating is investigated for the case of a negative Soret coupling between temperature and concentration gradients. Finite difference numerical simulations are performed for ethanol-water parameters subject to realistic boundary conditions. Traveling waves with modulated amplitudes and phase velocities, subharmonic standing waves, and synchronously modulated patterns with fixed spatial phase are found as stable solutions. The hysteretic transitions between subcritical traveling and standing waves that coexist bistably with the quiescent fluid state are investigated. Various diagnostic analysis tools are used to elucidate the complex spatiotemporal and bifurcation properties that are ultimately caused by nonlinear advection and mixing of concentration being very strong.