The kinematics and hydrodynamics of rapid escape manoeuvres executed by final-stage larvae of Enallagma cyathigerum were investigated using videography combined with a simple wake-visualisation technique. Two kinds of escape manoeuvres were identified: first, a 'rapid flex', comparable with the rapid C-start of fish, and, second, a 'rapid twist' that involves a helical contraction of the body i...

Vortex formation from a horizontal cylinder coincident with a free surface of a shallow water flow having a depth of 25.4 mm was experimentally investigated using the particle image velocimetry technique. Instantaneous and time-averaged flow patterns in the wake region of the cylinder were examined for three different cylinder diameter values under the fully developed turbulent boundary layer c...

1'~ experimental investigation of the wake behind a Meteor 4 EL?XW&Z has beon carried out, and theory used wherever possible to confirm a& ater.d the results &tamed. Xea~urements ehw that for the conditions oovered in these tests, the jet velocity has fallen to a negligible value by about 200-300 ft behinil the jet exrt. The act muld oe tiqected to persist Longest under take-o~cf conditims alth...

The pulsed flow about a circular non-centred orifice inside a cylindrical duct is analysed to obtain insight into the basic three-dimensional vortex dynamics that may be expected behind natural cardiac valves. The problem is approached by a highresolution numerical simulation. Results show how a small finite eccentricity generates a fully three-dimensional vortex wake that evolves quite differe...