In this paper, a compensated compactness framework is established for sonic-subsonic approximate solutions to the n-dimensional(n ≥ 2) Euler equations for steady irrotational flow that may contain stagnation points. This compactness framework holds provided that the approximate solutions are uniformly bounded and satisfy H−1 loc (Ω) compactness conditions. As illustration, we show the existence...

Hypersonic flows of nitrogen, oxygen, argon, and carbon dioxide near a toroidal ballute have been investigated numerically using the Direct Simulation Monte-Carlo technique under transition rarefied-gas flow conditions (Knudsen numbers from 0.005 to 10). Strong influences of the geometrical factor (a ratio of the distance between the axis of symmetry and the torus disk center, and the torus rad...

We demonstrate the use of a microfluidic stagnation point flow to trap and extend single molecules of double-stranded (ds) genomic DNA for detection of target sequences along the DNA backbone. Mutant EcoRI-based fluorescent markers are bound sequence-specifically to fluorescently labeled ds lambda-DNA. The marker-DNA complexes are introduced into a microfluidic cross slot consisting of flow cha...

A square splittered and unsplittered rod is placed in a turbulent boundary layer developed over a flat plate. The effect of the resulting disturbances on the local heat transfer coefficient is then studied. In both cases the square rod modifies the flow structure inside the boundary layer. As a result, a stagnation point, a jet and wake area are generated around the square rod, each making a co...

A novel velocimetry technique to probe the exhaust flow of a laboratory scale combustor is being developed. The technique combines the advantages of standard particle velocimetry techniques and the ultra-fast imaging capabilities of a streak camera to probe high speed flows near continuously with improved spatial and velocity resolution. This “Particle Streak Velocimetry” technique tracks laser...

This paper describes the passive flow control of fluid in the downstream direction of the circular tube and in tube banks by means of splitter plate. Heat transfer and pressure drop depend on complex flow pattern of fluid in tube banks, whereas pressure drop linked directly with the fluid pumping capacity. A primary focus is to review experimental, analytical and numerical works that had been c...

The steady laminar stagnation point flow of an incompressible electrically conducting micropolar fluid impinging on a permeable flat plate with uniform suction/injection is considered. A uniform magnetic field is applied normal to the plate. The effect of viscous dissipation is taken into account. The governing partial differential equations are transformed into ordinary differential equations....

The paper shows the results of the convective heat transfer prediction in turbulent axisymmetric jets impinging onto a flat plate using the newest version (2006) of the k-ω turbulence model of Wilcox [1]. Improvements to the heat transfer predictions are obtained in the strongly strained flow regions with the impingement invariant proposed by Manceau [2] together with the F1 function proposed b...

We develop a reduced order model for large-scale unsteadiness (vortex shedding) in a two-dimensional diffuser and study the mechanisms of active flow separation control. This model can estimate the vortex shedding frequency for inviscid flows by accounting for the accumulated vorticity flux in the diffuser. The model can also predict the stagnation pressure loss, which consists of two parts: A ...

The unsteady viscous flow in the vicinity of an axisymmetric stagnation point of an infinite moving cylinder with time-dependent axial velocity is investigated. The impinging free stream is steady with a strain rate k. An exact solution of the Navier-Stokes equations is derived in this problem. A reduction of these equations is obtained by use of appropriate transformations. The general self-si...