in this study, aerodynamic characteristics of a circular cylinder in an axial flow have been investigated numerically and experimentally. the model has been considered as a cylinder with truncated nose and fineness ratio of 3 (length to diameter ratio of 3). the investigation involves a series of wind tunnel measurements, flow visualization, and numerical simulation. we used different mach numb...

We investigate the behavior and consequences of the reverse shock that terminates the supersonic expansion of the baryonic wind which is driven by neutrino heating off the surface of (non-magnetized) new-born neutron stars in supernova cores. To this end we perform long-time hydrodynamic simulations in spherical symmetry. In agreement with previous relativistic wind studies, we find that the ne...

In the present paper, a supersonic wind-tunnel is designed to maintain a flow with Mach number of 3 in a 30cm×30cm test section. An in-house CFD code is developed using the Roe scheme to simulate flow-field and detect location of normal shock in the supersonic wind-tunnel. In the Roe scheme, flow conditions at inner and outer sides of cell faces are determined using an upwind biased algorithm. ...

– 2 – In this paper we explore the physics of time-dependent hydrodynamic collimation of jets from Young Stellar Objects (YSOs). Using parameters appropriate to YSOs we have carried out high resolution hydrodynamic simulations modeling the interaction of a central wind with an environment characterized by a toroidal density distribution which has a moderate opening angle of θ ρ ≈ 90 o The resul...

Supersonic air transport generates sonic booms that can affect people, animals and structures. There is a renewed interest in high-speed transport for civilian application. The widely used standard atmosphere for sonic boom prediction is neither capable of describing topographical variation, nor temporal variations, nor the impact of wind on the propagation of a sonic boom. However, within the ...

We present similarity solutions for adiabatic bubbles that are blown by winds having time independent mechanical luminosities and that are each mass-loaded by the hydrodynamic ablation of distributed clumps. The mass loading is ‘switched-on’ at a specified radius (with free-expansion of the wind interior to this point) and injects mass at a rate per unit volume proportional to Mr where δ = 4/3 ...

Particle Image Velocimetry (PIV) has become an important tool in modern flowfield diagnostics, in particular for subsonic flows. PIV systems have also been used to measure supersonic flows in supersonic wind tunnels, but only recently it has been shown that PIV can also be a valuable tool for high-speed supersonic flows in a shock tunnel (Haertig et al., 2001). At the ISL shock tunnel a PIV sys...

The heliosphere is the bubble the Sun carves out of the interstellar medium. The solar wind moves outward at supersonic speeds and carries with it the Sun’s magnetic field. The interstellar medium is also moving at supersonic speeds and carries with it the interstellar magnetic field. The boundary between the solar wind and the interstellar medium is called the heliopause. Before these plasmas ...

A wind passing over a surface may cause an instability in the surface such as the flapping seen when wind blows across a flag or waves when wind blows across water. We show that when a radially outflowing wind blows across a dense thin rotating disk, an initially flat disk is unstable to warping. When the wind is subsonic, the growth rate is dependent on the lift generated by the wind and the p...