The inability to capture the physics of solid-particle suspension in turbulent fluid flow is holding back application of multiphase computational fluid dynamics techniques to the many problems involving particle suspension in nature and society. We present a theory for particle suspension capacity near no-slip frictional boundaries of turbulent flows. The suspension capacity parameter Γ include...

We study the phenomenon of turbulence from the point of view of statistical physics. We discuss what makes the turbulent states different from the thermodynamic equilibrium and give the turbulent analog of the partition function. Then, using the soluble theory of turbulence of waves as an example, we construct the turbulent action and show how one can compute the turbulent correlation functions...

Current knowledge of the mechanics of alluvial channels depends very largely on calculations of turbulent shear stresses; typical examples are the beginning of motion of sediment particles and sediment transport in alluvial channels. If shear stress can be well defined in clear-water flows, comparatively little is known about shear stresses in sediment-laden flows. Einstein and Chien (1955) pro...

Aims. We study the dependence of turbulent transport coefficients, such as α effect and turbulent magnetic diffusivity, on shear and magnetic Reynolds number in the presence of helical forcing. Methods. We use three-dimensional direct numerical simulations with periodic boundary conditions and measure turbulent transport coefficients using the kinematic test field method. In all cases the magne...

Pollutant transport due to the turbulent wind flow around buildings is a complex phenomenon which is challenging to reproduce with Computational Fluid Dynamics (CFD). In the present study we use Large-Eddy Simulation (LES) to investigate the turbulent mass transport mechanism in the case of gas dispersion around an isolated cubical building. Close agreement is found between wind-tunnel measurem...

Modeling the primary atomization of turbulent liquid jets and sheets still remains an unsolved problem. Considering numerical grid resolutions typical for Large Eddy Simulations, the large scale liquid structures during primary breakup are well resolved, whereas all small scale structures are unresolved and thus require modeling. To help in the derivation of such subgrid models, DNS of the turb...

Arthrofactin is a biosurfactant produced by Pseudomonas sp. MIS38. We have reported that transposon insertion into spoT (spoT::Tn5) causes moderate accumulation of guanosine 3',5'-bispyrophosphate (ppGpp) and abrogates arthrofactin production. To analyze the linkage of SpoT function and ablation of arthrofactin production, we examined the spoT::Tn5 mutation. The results showed that spoT::Tn5 is...

We performed a comparative analysis between Roche Amplicor HIV-1 DNA test and CAPTAQ assay for the detection of HIV in 830 dried blood spot (DBS) pediatric samples collected in Mozambique. Our results demonstrated no statistical difference between these assays. The CAPTAQ assay approached nearly 100% repeatability/accuracy. The increased throughput of testing with minimal operator interference ...

The electroweak phase transition, if proceeding through nucleation and growth of bubbles, should generate large scale turbulent flow, which in turn generates magnetic turbulence and hence magnetic fields on the scale of turbulent flow. We discuss the seeding of this turbulent field by the motion of the dipole charge layers in the phase transition bubble walls, and estimate the strength of the p...

Three competing hypotheses have been proposed for the cortical representation of the blind spot. These are: (i) the regions surrounding the blind spot maintain their spatial values; (ii) the opposite sides of the blind spot are represented adjacently at the cortex, so that the blind spot is "sewn-up"; and (iii) the blind spot is sewn-up with compensation occurring in the immediate surround of t...