Pulsating cone-jets occur in a variety of electrostatic spraying and printing systems. This paper reports an experimental study of the pulsation frequency to reconcile two models based on a choked jet and an oscillating cone, respectively. The two regimes are demarcated by the ratio of the supplied flow rate (Qs) to the minimum flow rate (Qm) required for a steady Taylor cone-jet. When Qs . Qm,...

In the following paper, the effects of a choked jet exhausted from the base of a non-lifting body on its total and base drags at sub-sonic and transonic regimes has been numerically investigated. Having surveyed the results of some turbulence models and after comparing with experimental results, an appropriate turbulence model i.e. SST K-?, has been chosen and this model has been used in the su...

in this study, the effect of suction and the parameters such as suction amplitude, suction coefficient and suction jet length on naca0012 was evaluated. the turbulence employed model was the rsm model. suction jet is located in 10% of the chord length. the range of suction jet entrance velocity was selected from 0.1 to 0.5 of freestream velocity. the maximum increase in lift to drag ratio was s...

Core collapse of massive stars resulting in a relativistic fireball jet which breaks through the stellar envelope is a widely discussed scenario for gamma-ray burst production. For very extended or slow rotating stars, the jet may be unable to break through the envelope. Both penetrating and choked jets will produce, by photomeson interactions of accelerated protons, a burst of greater, greater...

This paper addresses the aerodynamic performance of Busemann-type supersonic biplanes at both design and offdesign conditions. An adjoint-based optimization technique is used to optimize the aerodynamic shape of the biplane to reduce the wave drag at a series of Mach numbers ranging from 1.1 to 1.7, at both acceleration and deceleration conditions. The optimized biplane airfoils dramatically re...

Flowmetry. Fluid-flow measurement and visualisation ................................................................................ 1 Measuring mass flow-rate ......................................................................................................................... 2 Accumulative weighting .............................................................................................

Highly relativistic jets are a key element of current gamma-ray burst models, where the jet kinetic energy is converted to radiation energy at optically thin shocks. High-energy neutrinos are also expected, from interactions of protons accelerated in the same shocks. Here we revisit the early evolution of a relativistic jet, while the jet is still inside the star, and investigate its neutrino e...