We study, from the numerical point of view, instabilities developed in a fluid layer with a free surface in a cylindrical container which is nonhomogeneously heated from below. In particular, we consider the case in which the applied heat is localized around the origin. An axisymmetric basic state appears as soon as a nonzero horizontal temperature gradient is imposed. The basic state may bifur...

The scallop theorem posits that a two-link system immersed in a fluid at low Reynolds number cannot achieve any net translation via cyclic changes in its hinge angle. Here, we propose an approach to “breaking” this theorem, based on a static separation between the centers of mass and buoyancy in a net neutrally buoyant system. This separation gives the system a natural equilibrium orientation, ...

Radio galaxies are known to inflate lobes of hot relativistic plasmas into the intergalactic medium. Here we present hydrodynamical and magnetohydrodynamical simulations of these hot plasma bubbles in FRII objects. We focus on the later stages of their evolution after the jet has died down and after the bow shock that surrounded the lobes at earlier stages has vanished. We investigate the evolu...

Buoyancy effects in unstably stratified mixing layers express themselves through gravity currents of heavy fluid which propagate in an ambient lighter fluid. These currents are encountered in numerous geophysical flows, industrial safety and environmental protection issues [1] . During transition to turbulence a strong distortion of the separating interface between regions containing ‘heavy’ or...

Rubella virions demonstrated by negative-contrast electron microscopy have recently been reported to range from 500 to 750 A in diameter and to have amorphous pleomorphic envelopes (J. M. Best et al., Lancet 2:237, 1967). Consonant with these observations, sedimentation studies have indicated a diameter of 850 A and ultrafiltration experiments, 900 A (B. Russell et al., J. Gen. Virol. 1:305, 19...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Abstract A series of Large Eddy Simulations (LES) are performed to investigate the penetration of starting buoyant ...

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