Time-dependent patterns in atomistically simulated convection

Periodically varying roll patterns have been produced in molecular-dynamics simulation of two-dimensional Rayleigh-Bénard convection using a hard-disk fluid in a square container with nonslip walls. In order to achieve the sufficiently high Rayleigh numbers required for clearly resolved time-dependent behavior the calculations involved systems containing almost 6×${10}^4$ particles, an order of magnitude greater than the number needed to observe stationary convection patterns.