Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux Π(u), we demonstrate that, for stably stratified flows, the kinetic energy spectrum E(u)(k)∼k(-11/5), the potential energy spectrum E(θ)(k)∼k(-7/5), and Π(u)(k)∼k(-4/5) are consistent with the Bolgiano-Obukhov scaling. This scaling arises due to the conversion of kinetic energy to the potential ener...

10 INTRODUCTION 11 MATERIALS AND METHODS 14 Determination of body density 14 Determination of initial air-store volume 15 Air-store volume and buoyancy 16 Air-store volume calculation 18 Air-store PO2 measurement 18 Effect of temperature and aquatic PO2 on voluntary dive duration 19 RESULTS 20 Determination of density 20 Mechanisms of air-store volume regulation 20 Initial air-store volume in f...

We describe a Newton-based nonlinear solver for immiscible two-phase transport in the presence of significant viscous, buoyancy, and capillary forces. The evolution of CO2 plumes in heterogeneous saline aquifers, especially during the post-injection period, is an important example of this class of problem. The flux (fractional flow) function, which is strongly nonlinear function of saturation, ...

In the stratified ocean, vertical motions arise from both adiabatic and diabatic mechanisms. Diapycnal advection is the vertical component of flow across an isopycnal surface which occurs when mixing produces a divergent flux of buoyancy. Buoyancy forcing of the lateral flow by vortex stretching occurs when diapycnal advection rates vary with depth. Microstructure observations of enhanced turbu...

Direct numerical simulation (DNS) is applied to investigate properties of katabatic and anabatic flows along thermally perturbed (in terms of surface buoyancy flux) sloping surfaces in the absence of rotation. Numerical experiments are conducted for homogeneous surface forcings over infinite planar slopes. The simulated flows are the turbulent analogs of the Prandtl (1942) one-dimensional lamin...

double-diffusive mixed convection in a lid-driven square enclosure filled with al2o3-water is numerically investigated. two-dimensional nonlinear governing equations are discretized using the control volume method and hybrid scheme. the equations are solved using simpler algorithm. the results are displayed in the form of streamlines, isotherms, and iso-concentrations when the richardson number...

Abstract: Rainbow schlieren deflectometry combined with high-speed digital imaging was used to study buoyancy effects on flow structure of a helium jet discharged vertically into air. The experimental data were taken using the 2.2-sec drop tower facility at the NASA John H. Glenn Research Center in Cleveland, Ohio. The test conditions pertained to jet Reynolds number of 490 and jet Richardson n...

When a subject is totally immersed in water while holding his breath, a loss of buoyancy occurs.This phenomenon can be demonstrated by resting the subject on 1 pan of a balance, the loss of buoyancy being reflected as a gain in weight on the balance. This gain in weight (or loss of buoyancy) was first observed by us while determining body density by an underwater weighing method (1). This gain ...

[1] Laboratory and numerical experiments show that when a chemically different layer overlies a hotter but otherwise denser layer, analogous to continental mantle lithosphere over asthenosphere, convective stability depends strongly on both the critical Rayleigh number and the buoyancy number, B, of the lithosphere-like layer. Sufficient cooling at low buoyancy number results in an oscillatory ...

Centrifugal microfluidic systems bear great potential for applications where ruggedness, portability, ease-of-use, and cost efficiency are critical. However, due to the unidirectional nature of the centrifugal pumping force, the number of sequential process steps which can be integrated on these “Lab-on-a-Disc” (LoaD) devices is limited by their finite radial extension. To significantly widen t...