Wakes of towed and self-propelled bodies moving in stably stratified flows are of relevance to environmental and ocean engineering applications. To date, the majority of studies focused on the wakes of spheres and cylinders in stratified flows. Stable stratification modulates the wake dynamics, leading to a significantly different flow compared to non-stratified wakes. The wakes of spheres and ...

Computer simulations of two-phase gas-liquid pipe flow cases have been performed with the commercial code STAR-CD using the VOF method and the results are illustrated in this paper. Computed pressure losses for stratified flow and stratified-wavy flow and time-averaged liquid levels are compared against measured data, showing good agreement with the experimental data. To achieve these results, ...

In this paper, the feasibility of using an X-ray tube instead radioisotope sources for measuring volume fractions gas, oil, and water in two typical flow regimes three-phase flows, namely, annular stratified, is evaluated. This study’s proposed detection system composed tube, a 1 inch × NaI detector, one Pyrex-glass pipe to model different regimes, stratified. Group method data handling (GMDH),...

Transient development of perturbations in inviscid stratified shear flow is investigated. Use is made of closed form analytic solutions that allow concise identification of optimally growing plane-wave solutions for the case ofan unbounded flow with constant shear and stratification. For the case of channel flow, variational techniques are employed to determine the optimally growing disturbance...

We study the inviscid damping of Couette flow with an exponentially stratified density. The optimal decay rates of the velocity field and the density are obtained for general perturbations with minimal regularity. For Boussinesq approximation model, the decay rates we get are consistent with the previous results in the literature. We also study the decay rates for the full Euler equations of st...

Direct numerical simulations (DNS) of stably-stratified, turbulent plane Couette flow are currently being performed on the XC-4000. The friction Reynolds number is kept approximately constant, Reτ 540 and the Richardson number Riw varies between 0 and 0.1. The flow is divided into two regions: the region close to the wall and the core region. The region close to the wall presents strong velocit...

The energy evolution in buoyancy-generated turbulence subjected to shear depends on the gradient Richardson number Ri and the stratification number St, which is a ratio of the time scale of the initial buoyancy fluctuations to the time scale of the mean stratification. During an initial period, the flow state evolves as in the unsheared case. After this period, shear generates fluctuating veloc...

The baroclinic tidal regime of the fjord Loch Etive (Scotland) is studied. Analysis is performed on the basis of both in situ data and numerical simulations, with the use of a fully nonlinear nonhydrostatic fine-resolution model. It was found that the crest of the sill that separates Loch Etive into inner and outer parts is subjected to a supercritical flow regime with maximum Froude numbers in...

VOLUME 84, OCTOBER 2006 INTRODUCTION This work is motivated by a problem encountered in certain mixing processes that employ a centre line injector upstream of a static mixer. Static or motionless mixers have been adopted for a large number of blending and dispersion operations because they offer attractive features such as closed-loop operation, and no moving parts, in contrast to continuously...