MEASUREMENTS OF A 2-D NONBUOYANT JET IN A WAVE ENVIRONMENT

This paper considers the dispersion of a 2-D non-buoyant jet discharge d beneath a series of progressive gravity waves. A new experimental in vestigation is described in which the dispersion of a jet in a wave en vironment is compared to an identical discharge in a stagnant ambient. This comparison highlights the additional wave-induced mixing and sho ws that the oscillatory wave motion has a significant effect upon both the mean velocity profiles and the magnitude of the turbulent fluctua tions. In particular, the experimental data suggests that the wave mot ion encourages a transfer of energy into the turbulent components of t he flow field. This effect is most pronounced within the ''zone of flo w establishment'', and leads to a significant increase in the effectiv e Reynolds stresses. This in turn creates a region of intense fluid mi xing which is characterised by a large reduction in the axial velocity components and a substantial increase in the rate of entrainment. The experimental data is also compared to both the existing integral solu tions and a Lagrangian formulation which is similar to that proposed b y Chin (1988). Although neither of these solutions is able to model th e flow immediately downstream of the outlet, the Lagrangian solution p rovides an improved description of the mean velocity within the ''zone of established flow''.