SUMMARY Wind-tunnel tests have been made to assess the aerodynamic potential of an overwing installation for fan-jet engines on a typlcal modern transport aeroplane. Low-speed tests on a complete model with free-flow nacelles and tests at higher speed on a partial model incorporating a blown jet are described; it is concluded that the lift-dependent drag associated with such an installation wou...

We present the results of 3D hydrodynamic simulations gamma-ray burst (GRB) jet emanating from a massive star with particular focus on formation high-velocity quasi-spherical ejecta and jet-induced chemical mixing. Recent early-time optical observations supernovae associated GRBs (e.g., GRB 171205A/SN 2017iuk) indicate considerable amount heavy metals in outer layers ejecta. Using our simulatio...

The blades of a vertical axis wind turbine (VAWT) rotor see an inconsistent angle of attack through its rotation. Consequently, VAWT blades generally use symmetrical aerofoils with a lower lift-to-drag ratio than cambered aerofoils tailored to maximise horizontal axis wind turbine rotor performance. This paper considers the feasibility of circulation controlled (CC) VAWT blades, using a tangent...

This contribution presents different approaches for the modeling of air entrainment under water by plunging jets in CFD codes. In simulations which include the full length of the jet and its environment, the process of bubble generation can not be resolved due to computational limitations. This is why the air entrainment has to be modeled in meso-scale simulations. In the frame of an EulerEuler...

Numerical modeling of direct hydrogen injection and in-cylinder mixture formation is performed in this paper. Numerical studies on direct-injection hydrogen engines are very limited due mainly to the complexity in modeling the physical phenomena associated with the high-velocity gas jet. The high injection pressure will result in a choked flow and develop an underexpanded jet at the nozzle exit...

We consider the Rayleigh–Taylor instability in the early evolution of the rarefied radio bubbles (cavities) observed in many cooling–flow clusters of galaxies. The top of a bubble becomes prone to the Rayleigh–Taylor instability as the bubble rises through the intra–cluster medium (ICM). We show that while the jet is powering the inflation, the deceleration of the bubble–ICM interface is able t...

The effects of an oscillatory zero-net-mass-flux jet (i.e. synthetic jet) acting on a separated flow over a hump are investigated in terms of two actuation parameters – actuator position and forcing frequency. By considering the vorticity flux balance and introducing a centroid of vorticity production over the hump surface, lift and drag acting on the hump can be expressed as a function of this...

We employ the string/gauge theory correspondence to study properties of strongly coupled quark-gluon plasmas in thermal gauge theories with a large number of colors and flavors. In particular, we analyze non-critical string duals of conformal (S)QCD, as well as ten dimensional wrapped fivebrane duals of SQCD–like theories. We study general properties of the dual plasmas, including the drag forc...

Aerodynamic drag reduction is required with new stringent constraints on pollutant emissions and fuel efficiency of ground vehicles. In this context, active flow control a promising approach to achieve target. This study focuses applying different strategies the square-back Ahmed model reduce aerodynamic drag. A steady blowing jet, synthetic jet an unsteady are located at back edges as devices....

The thin jet model applied by Spence to the study of the jet flap is combined with the vortex sheet model applied by Mangler and Smith to the study of leading-edge separation, to study the effect of blowing from the leading-edges of a cambered wing. The numerical techniques used to solve problems of leading-edge separation have been improved, and in the present investigation solutions have been...