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A turbulent axisymmetric bluff body wake is investigated using large eddy simulation to uncover key flow dynamics and structures. The effect of low-frequency high-frequency pulsed jet forcing at the point separation studied reveal underlying mechanisms involved in base pressure changes, which provide a reference for drag reduction active control.

We present results from axisymmetric, time-dependent magnetohydrodynamical (MHD) simulations of a gaseous envelope collapsing onto a black hole (BH). We consider gas with so small angular momentum that, if not for the effects of MHD, the flow would accrete directly onto a BH. We find that after an initial transient, the flow settles into a configuration with four components: (i) a radial equato...

An axisymmetric MHD model is examined analytically to illustrate some key aspects of the physics of hot and magnetized outflows which originate in the near environment of a central gravitating body. By analyzing the asymptotical behaviour of the outflows it is found that they attain a variety of shapes such as conical, paraboloidal or cylindrical. However, non cylindrical asymptotics can be ach...

A Lattice-Boltzmann model for high-speed non-isothermal subsonic flows is used to simulate the unsteady jet exhausting from a short-cowl axisymmetric coaxial nozzle and the associated noise. The primary and secondary jet exit Mach numbers are 0.87 and 0.90, respectively, the secondary jet Reynolds number is 2.8 · 10, and the primary to secondary temperature ratio is 2.7. The far-field is comput...

Modelling of deep VLA images of the jets in FR I radio galaxies has allowed us to derive their three-dimensional distributions of velocity, emissivity and magnetic-field structure on kiloparsec scales. By combining our models of jet kinematics with measurements of the external pressure and density derived from Chandra observations, we can also determine the jet dynamics via a conservation-law a...

Viscous fluid exiting a long horizontal circular pipe develops complex structure comprising primary jet above and smaller secondary below with thin curtain connecting them. We present here combined experimental, theoretical numerical study of this 'Torricelli's curtain' phenomenon, focusing on the factors that control its morphology. propose model for in which particle trajectories result from ...

An axisymmetric full Navier-Stokes computational fluid dynamics study is conducted to examine nozzle exhaust jet plume effects on the sonic boom signature of a supersonic aircraft. A simplified axisymmetric nozzle geometry, representative of the nozzle on the NASA Dryden NF-15B Lift and Nozzle Change Effects on Tail Shock research airplane, is considered. The computational fluid dynamics code i...

A series of coaxial dual-stream jets issuing into quiescent air was investigated using Reynolds-averaged Navier-Stokes calculations with linear two-equation and nonlinear two-equation explicit algebraic stress turbulence modeling. Comparisons of calculated mean flowfield development were made with experimental data. For all cases, a single axisymmetric convergent-divergent nozzle provided a Mac...

The paper considers heat transfer characteristics of thin film flow over a hot horizontal flat plate resulting from a cold vertical jet of liquid falling onto the surface. A numerical solution of high accuracy is obtained for large Reynolds numbers using the modified Keller box method. For the flat plate, solutions for axisymmetric jets are obtained. In a parallel approximation theory, an advan...