Jet deflection and hairpin bends

The deflection of a hydrodynamic jet via an oblique internal shock is studied. The pressure increase across the shock and the confinement of the shocked jet are maintained by the ramming of the bend through the ambient medium. A steady flow pattern is found in the reference frame co-moving with the bend: the external ram pressure gradually bends the deflected jet by up to 1800. The shock polar method is used to quantify this model and it is found that changes in the initial angle of deflection and fluid dynamic instabilities will destroy this flow pattern for heavy jets. The model is applied to the U-shaped channels in the radio galaxies 3C 401 and 4C 32.69 and the head-tail source IC 708. (author)