An experimental study on the mixing of two plane, unventilated, parallel jets reveals an instability characterized by sinuous ‘‘flapping’’ of the jets and enhanced mixing of the jets with the ambient fluid. The frequency and amplitude of the instability is shown to be a function of the jets’ spacing and momentum flux ratios, with the maximum mixing occurring for cases with matched momentum flux...

I propose a model for the formation of slow-massive-wide (SMW) jets by accretion disks around compact objects. This study is motivated by claims for the existence of SMW jets in some astrophysical objects such as in planetary nebulae (PNs) and in some active galactic nuclei in galaxies and in cooling flow clusters. In this model the energy still comes from accretion onto a compact object. The a...

I examine a mechanism by which two fast narrow jets launched by a newly formed neutron star (NS), or a black hole (BH), at the center of a core collapse supernovae (CCSN), form two slow massive wide (SMW) jets. Such SMW jets are assumed as initial conditions in some numerical simulations that demonstrate that SMW jets can expel the rest of the collapsing star. The original fast narrow jets must...

We study the bending of jets in binary stellar systems. A compact companion accretes mass from the slow wind of the mass-losing primary star, forms an accretion disk, and blows two opposite jets. These fast jets are bent by the slow wind. Disregarding the orbital motion, we find the dependence of the bending angle on the properties of the slow wind and the jets. Bending of jets is observed in p...

We calculate the parton level cross section for the production of two jets that are far apart in rapidity, subject to a limitation on the total transverse momentum Q0 in the interjet region. We specifically address the question of how to combine the approach which sums all leading logarithms in Q/Q0 (where Q is the jet transverse momentum) with the BFKL approach, in which leading logarithms of ...

Context. Astrophysical jets from various sources seem to be stratified, with a fast inner jet and a slower outer jet. As it is likely that the launching mechanism for each component is different, their interface will develop differential rotation, while the outer jet radius represents a second interface where disruptions may occur. Aims. We explore the stability of stratified, rotating, relativ...

In forced two-dimensional turbulence on a rotating sphere, it is well known that a multiple zonal-band structure, i.e. a structure with alternating eastward and westward jets, emerges in the course of time development. The multiple zonal-band structure then experiences intermittent mergers and disappearances of zonal jets, and a structure with only a few large-scale zonal jets is realised as an...