125301-7474 IJET-IJENS @ February 2012 IJENS I J E N S Abstract—To better understand the vacuum arc remelting (VAR) process, a 3D finite element model is established to analyzing the electromagnetic, temperature and flow fields of titanium alloy ingot during steady state melting process using ANSYS software. The research results show that the current flows from the crucible to consumable electr...

Plumes are typically formed when a continuous source of buoyancy is supplied at a localized source. We studied laminar plumes where buoyancy is supplied by an autocatalytic chemical reaction: The iodate-arsenous acid (IAA) reaction. The nonlinear kinetics of the IAA reaction produces a sharp propagating front at which buoyancy is produced by exothermicity and compositional change. When the reac...

It is widely thought that changes in both the surface buoyancy fluxes and wind stress drive variability in the Atlantic meridional overturning circulation (AMOC), but that they drive variability on different time scales. For example, wind forcing dominates short-term variability through its effects on Ekman currents and coastal upwelling, whereas buoyancy forcing is important for longer time sc...

A class of unsteady free convection flows over a differentially cooled horizontal surface is considered. The cooling, specified in terms of an imposed negative buoyancy or buoyancy flux, varies laterally as a step function with a single step change. As thermal boundary layers develop on either side of the step change, an intrinsically unsteady, boundary-layer-like flow arises in the transition ...

Abstract This paper presents a systematic study of flow and heat transfer mechanisms in compressor disk cavity with an axial throughflow under centrifugal buoyancy-driven convection, comparing previously published experimental data. Wall-modeled large-eddy simulations (WMLES) are conducted for six operating conditions, covering range rotational Reynolds number (3.2×105−2.2×106), buoyancy parame...

Ceramic-based hollow spheres are considered a great driving force for many applications such as offshore buoyancy modules due to their large diameter to wall thickness ratio and uniform wall thickness geometric features. We have developed such thin-walled hollow spheres made of alumina using slip casting and sintering processes. A diameter as large as 50 mm with a wall thickness of 0.5-1.0 mm h...

Measurements of turbulent fluctuations of horizontal and vertical components of velocity, salinity and suspended particulate matter are presented. Turbulent Prandtl numbers are found to increase with stratification and to become larger than 1. Consequently, the vertical turbulent mass transport is suppressed by buoyancy forces, before the turbulent kinetic energy (TKE) and vertical turbulent mo...

Buoyancy is a de-stabilizing force for diving cormorants that forage at shallow depths. Having to counter this force increases the cost of transport underwater. Cormorants are known to be less buoyant than most water birds but are still highly buoyant (rho= approximately 0.8 kg m(-3)) due to their adaptations for aerial flight. Nevertheless, cormorants are known to dive at a wide range of depth...

Shear and buoyancy are both known to contribute to the development of boundary layers, whose characteristics include turbulent mixing of scalar quantities within the layer. Purely shear-driven boundary layers include airflow over an airplane wing and stream flow over a bottom surface. Buoyancy-driven boundary layers include the atmospheric convective boundary layer (CBL) and the upper levels of...

In a stratified rotating fluid, frictionally driven circulations couple with the buoyancy field over sloping topography. Analytical and numerical methods are used to quantify the impact of this coupling on the vertical circulation, spindown of geostrophic flows, and the formation of a shelfbreak jet. Over a stratified. slope, linear spindown of a geostrophic along-isobath flow induces cross-iso...