Flow coupling mechanisms in two-layer Rayleigh–Benard convection

 Rayleigh-Benard convection in two-layer systems is characterized by two distinct modes of flow coupling. These are: thermal coupling and mechanical coupling. Intellegible observations of the temperature field for both coupling mechanisms are provided. The flow coupling mechanisms are experimentally characterized as a function of the contrast in the buoyancy driving forces and in the viscosities of the two layers. Aside from the flow coupling between the layers, flow patterns in each layer, and their corresponding spatial transitions are found to be similar to those reported for single layer convection in rectangular boxes.