Light experiences a non-uniformly moving medium as an effective gravitational field, endowed with an effective metric tensor g̃μν = η μν + (n2 − 1)uμuν , n being the refractive index and uμ the fourvelocity of the medium. Leonhardt and Piwnicki [Phys. Rev. A 60, 4301 (1999)] argued that a flowing dielectric fluid of this kind can be used to generate an ’optical black hole’. In the Leonhardt-Piwn...

We examine the flow of viscoelastic fluids with various shear and elongational properties in axisymmetric and planar 4:1 contractions, under creeping flow conditions. Particular attention is paid to the influence of elongational viscosity upon vortex enhancement/inhibition. Simulations are performed with a novel hybrid finite volume/element algorithm. The momentum and continuity equations are s...

The influence of strong rotation on the flame length in firewhirls (normalized by the fuel supply rate) is investigated analytically. A new prediction for the length of the flame in firewhirls with strong rotation is obtained by introducing the compensating regime of vortical flows. The prediction is in a good agreement with experimental results.

In today's CFD-assisted turbomachinery design, a primary objective is to minimize the effects of vortices. Their automatic identification, along with other flow structures, in numerical data is a current research topic. This paper presents a novel method to find vortex hulls in turbomachinery flows automatically. Based on a vortex core line that is the centerline of the vortex, the method is ab...

Fishes have an enormous diversity of body shapes and fin morphologies. From a hydrodynamic standpoint, the functional significance of this diversity is poorly understood, largely because the three-dimensional flow around swimming fish is almost completely unknown. Fully three-dimensional volumetric flow measurements are not currently feasible, but measurements in multiple transverse planes alon...

Flow separation at the vehicle’s rear end is the major cause of an aerodynamic drag in a car. In order to delay the flow separation at the rear, bump-shaped vortex generators at the roof end of a car are tested in this paper for two different types of car models Sedan and Hatchback. The aerodynamic analysis is carried out using GAMBIT and FLUENT for Sedan and Hatchback models. Vortex Generators...

In this paper, we describe new techniques for detecting vortices and regions of separated flow with application to visualization of large-scale computational fluid dynamics data sets. The vortex core detection algorithm is based on ideas derived from combinatorial topology, specifically, Sperner’s lemma. The algorithm to detect regions of separated flow is based on the assumption that each pair...

analyzing the vortex-induced vibration of a slender marine structure withlength to diameter ratio up to 200 is the objective of this study. this slender is free to move in both in-line and cross flow directions and immersed completely in water. three different types of shear currents pass on it and cause to vibrate slender in different forms. nowadays, these vibrations are very important for de...