We experimentally investigate the effect of particles on the dynamics of a gas bubble rising in a liquid-solid suspension while the particles are equally sized and neutrally buoyant. Using the Stokes number as a universal scale, we show that when a bubble rises through a suspension characterized by a low Stokes number (in our case, small particles), it will hardly collide with the particles and...

We experimentally and theoretically analyze the propagation of weak-signal field pulses under the conditions of electromagnetically induced transparency (EIT) in hot Rb vapor, and study the effects of resonant four-wave mixing (FWM). In particular, we demonstrate that in a doublesystem, formed by the strong control field with the weak resonant signal and a far-detuned Stokes field, both continu...

Given a nonstationary trajectory of the Navier–Stokes system, a finitedimensional feedback boundary controller stabilizing locally the system to the given solution is constructed. Moreover the controller is supported in a given open subset of the boundary of the domain containing the fluid and acts normal to the boundary. In a first step a controller is constructed that stabilizes the linear Os...

One of the major applications of the Domain Decomposition TimeMarching Algorithm is the coupling of the Navier-Stokes systems with Boltzmann equations in order to compute transitional ows. Another important application, is the coupling of a global Navier-Stokes problem with a local one in order to use di erent modelizations and/or discretizations. Both of these applications involve a global Nav...

In this paper, we study the dynamics of a two-dimensional stochastic Navier-Stokes equation on a smooth domain, driven by multiplicative white noise. We show that solutions of the 2D Navier-Stokes equation generate a perfect and locally compacting C1,1 cocycle. Using multiplicative ergodic theory techniques, we establish the existence of a discrete non-random Lyapunov spectrum for the cocycle. ...

We present first observations of solar polarization with a new imaging polarimetry system that simultaneously records three Stokes components, I , Q, V or I , U , V , in a single CCD. This instrument is an intermediate version on the way to ZIMPOL II (Zürich Imaging Stokes Polarimeter II), which will record all four Stokes parameters (Stenflo et al. 1992). The principle of operation is based on...