We develop a class of lters based upon the numerical solution of high-order elliptic problems in l R d that allow for independent determination of order and cut-oo wave number and that default to classical Fourier-based lters in homogeneous domains. However, because they are based on the solution of a PDE, the present lters are not restricted to applications in tensor-product-based geometries a...

We provide a selective review of recent progress in the analysis of several physiological and physiologically inspired fluid-structure interaction problems, our aimbeing to explain the underlying physicalmechanisms that cause the observed behaviors. Specifically, we discuss recent studies of self-excited oscillations in collapsible tubes, focusing primarily on studies of an idealized model syst...

Instantaneous streamlines are commonly used to visualize particle paths in steady flows. It is shown, however, that streaklines are often more appropriate for unsteady flows. The typical size of unsteady flow simulations makes interactive visualization difficult if not impossible. Two common approaches for visualizing unsteady flows are described. The advantages and disadvantages of each are di...

Thin film flows naturally arise in a wide variety of industrial and environmental problems ranging from microchip manufacturing, structured packing to lava flows in geology. In particular, wind-driven flows of liquid films are of great interests for deeper understanding of aircraft icing and better design of anti-icing and de-icing strategies. Currently, most thickness mapping techniques involv...

Abstract Thermospheric waves occurring around the time of the 14 July 2000 solar flare were investigated using the Global Ionosphere and Thermosphere Model. The simulation results showed that extensive acoustic and gravity waves were excited by the solar flare in the subsolar region. The subsolar buoyancy period at 400 km altitude was approximately 16 min. Gravity waves with frequencies lower t...

The most important property of a fluid is its viscosity, it determines the flow properties. If one simulates a fluid using a particle model, calculating the viscosity accurately is difficult because it is a collective property. In this article we describe a new method that has a better signal to noise ratio than existing methods. It is based on using periodic boundary conditions to simulate cou...

In this work we propose an effective viscosity criterion for the stabilization of annular gas-liquid and liquid-particle flows and an inertial mechanism which drives waves into slugs in slugging gas-liquid flows. Annular flow is stable when the fluid having the higher effective viscosity occupies the core region and the lower viscosity fluid is the annulus. The eddy viscosity criterion is shown...

This article addresses the low Weissenberg asymptotic analysis (Newtonian limit) of some macroscopic models of viscoelastic fluid flows in the framework of global weak solutions. We investigate the convergence of the corotational Johnson-Segalman, the FENE-P, the Giesekus and PTT models. Relying on a priori bounds coming from energy or free energy estimates, we first study the weak convergence ...

The motions of a passive scalar â in a general high-frequency oscillating flow are studied. Our aim is threefold: (i) to obtain different classes of general solutions; (ii) to identify, classify, and develop related asymptotic procedures; and (iii) to study the notion of drift motion and the limits of its applicability. The used mathematical approach combines a version of the two-timing method,...