Turbulent flow is a difficult issue in fluid dynamics, the rules of which have not been totally revealed up to now. Fluid in turbulent state will result in a greater frictional force, which must consume great energy. Therefore, it is not only an important influence in saving energy and improving energy utilization rate but also an extensive application prospect in many fields, such as ship doma...

The authors study the stability of a barotropic sinusoidal meridional flow on a b plane. Because of bottom drag and lateral viscosity, the system is dissipative and forcing maintains a basic-state velocity that carries fluid across the planetary vorticity contours; this is a simple model of forced potential vorticity mixing. When the Reynolds number is slightly above the stability threshold, a ...

A 0-450 Hertz bandwidth, voice coil actuated, proportional sleeve valve is designed to modulate air mass flow by controlling the throat area of a choked flow. The valve was designed to deliver a mass flow of 0.072 kg/s (0.16 lbm/s) with a maximum valve throat area of 41 mm (0.064 in.), a 689 kPA (100 psid) pressure difference across the valve, and 20 C, (68 F) air supply. The valve was develope...

Times of arrival of high energy neutrinos encode information about their sources. We demonstrate that the energy-dependence of the onset time of neutrino emission in advancing relativistic jets can be used to extract important information about the supernova/gamma-ray burst progenitor structure. We examine this energy and time dependence for different supernova and gamma-ray burst progenitors, ...

in this study, the time-average velocity in the near wake of a two-dimensional notch-back car model that located in the wake of a trailer has been investigated. the present experiments were carried out in an open circuit low-speed wind tunnel made by fara sanjesh saba ltd, in iran and was used to simulate uniform air flow. results show: at the close spacing, time- average velocity profile at th...

Both long-duration gamma-ray bursts (LGRBs) from core collapse of massive stars and short-duration GRBs (SGRBs) mergers binary neutron star (BNS) or star--black hole (NSBH) are expected to occur in the accretion disk active galactic nuclei (AGNs). We show that GRB jets embedded migration traps AGN disks promised be choked by dense material. Efficient shock acceleration cosmic rays at reverse is...