We generate tunable picosecond anti-Stokes pulses by four-wave mixing of two picosecond pump and Stokes pulse trains in a photonic-crystal fiber. The visible, spectrally narrow anti-Stokes pulses with shifts over 150 nm are generated without generating other spectral features. As a demonstration, we employ the generated anti-Stokes pulses as reference pulses in an interferometric coherent anti-...

Submitted for the DFD10 Meeting of The American Physical Society Effect of inter-particle collision in particle-laden homogeneous isotropic turbulence OHJOON KWON, CHANGHOON LEE, Yonsei University — It has been known that Inter-particle collision of small spherical particles in particle laden homogeneous isotropic turbulence modifies the statistical characteristics of particle behaviour. For ex...

The mixing dynamics of granular materials immersed in a liquid was experimentally studied in a quasi-2D rotating drum. A DV (SONY DCR-TRV900 NTSC) motion corder analyzer was used to record the motions of granular materials. The effects of interstitial fluid viscosity and filling degree on the mixing index, mixing rate constant, and dynamic repose angle in the rotating drum were investigated and...

Initial results of an ongoing Navier-Stokes Computational Fluid Dynamics study of horizontal axis tidal current turbine hydrodynamics are presented. Part of the underlying motivation is assessing the effects of the Reynolds number on turbine performance and loads in steady and unsteady flow regimes. The study aims at a) providing initial verification and validation of Navier-Stokes CFD for stea...

We give an overview of the ideas central to some recent developments in the ergodic theory of the stochastically forced Navier Stokes equations and other dissipative stochastic partial differential equations. Since our desire is to make the core ideas clear, we will mostly work with a specific example: the stochastically forced Navier Stokes equations. To further clarify ideas, we will also exa...

We study the low Mach low Freude numbers limit in the compressible Navier-Stokes equations and the transport equation for evolution of an entropy variable – the potential temperature Θ. We consider the case of well-prepared initial data on ”flat” tours and Reynolds number tending to infinity, and the case of ill-prepared data on an infinite slab. In both cases, we show that the weak solutions t...

This paper is devoted to the low Mach number limit of weak solutions to the compressible Navier-Stokes equations for isentropic uids in the whole space R d (d = 2 or 3). This problem was investigated by P.L. Lions and N. Masmoudi 19]. We present here a diierent approach based upon Strichartz' estimates for the linear wave equation like in 21] in the inviscid case, which improves the convergence...

We present a space-time hierarchical solution concept for optimization problems governed by the time-dependent Stokes– and Navier–Stokes system. Discretisation is carried out with finite elements in space and a one-step-θ-scheme in time. By combining a Newton solver for the treatment of the nonlinearity with a space-time multigrid solver for linear subproblems, we obtain a robust solver whose c...

A method of fundamental solutions has been used to study adiabatic transition amplitudes in two energy level systems for a class of Hamiltonians allowing some simplifications of Stokes graphs corresponding to such transitions. It has been shown that for simplest such cases the amplitudes take the Nikitin Umanski form but for more complicated ones they are formed by a sum of terms strictly relat...

We recall the non-Abelian Stokes theorem for the Wilson loop in the Yang –Mills theory and discuss its meaning. Then we move to ‘gravitational Wilson loops’, i.e. to holonomies in curved d = 2, 3, 4 spaces and derive ‘non-Abelian Stokes theorems’ for these quantities as well, which are similar to our formula in the Yang–Mills theory. In particular we derive an elegant formula for the holonomy i...