Structural and dynamical properties of nonlinear traveling-wave states in binary fluid layers heated from below are determined by numerical integration of the proper hydrodynamic field equations with experimental horizontal boundary conditions. The fluid separates into traveling rolls of alternating high and low concentration. Phase differences drive lateral currents and Reynolds stresses lateral mean flow.

The stability behavior of the conductive state of binary gas mixtures in the Rayleigh-Benard setup is significantly altered in comparison to binary liquid mixtures due to their different thermodynamic and transport properties. In particular, the Dufour effect influences dramatically the topology and the existence ranges of the oscillatory and stationary instabilities for Dufour and Lewis numbers that are typical in gas mixtures. We present a detailed investigation of the changes of the stability properties for several types of boundary conditions including the realistic no-slip, impermeable ones.

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