A previously given formalism for the steady state statistical operator ϱη (t) is illustrated for the case of a periodically driven oscillator coupled to a bath of oscillators. The application to several types of observables is investigated. Explicit evaluation shows that ϱη (t) gives the...

We use FLUENT to calculate the wind profile over barchans and transverse dunes. The form of the streamlines of flow separation at the lee side of the dunes is determined for a symmetric barchan dune in three dimensions, and for the height profile of a measured transverse dune field in the...

The motion of dunes and their morphology is a fascinating, largely unexplored subject. Already the barchan, the simplest moving dune, poses many questions. We will present some results of field measurements on desert and costal dunes. Then we will present a model which consists of three coupled...