Experiments on vertical turbulent plane jets in water of finite depth

Detailed experiments on vertical turbulent plane jets in water of finite de pth were carried out in a two-dimensional water tank. The jet velocities we re measured with a laser Doppler velocimeter (LDV). The LDV measurement cov ers the entire flow regime: the zone of flow establishment (ZFE), the zone of established flow (ZEF), the zone of surface impingement (ZSI), and the z one of horizontal jets (ZHJ). From the experimental results, the following conclusions are reached. First, the jet flow is independent of the Reynolds number if the Reynolds number is sufficiently large to produce a turbulent jet. Second, in the initial ZFE, the jet flow is nonsimilar and is charact erized by the two free shear layers along the two edges of the jet orifice. Third, the jet flow in ZEF is self-similar. Both mean and fluctuation velo cities are scaled with the mean jet centerline velocity. The turbulent shea r stress is predictable by Prandtl's third eddy viscosity model. The spread ing of the confined vertical jets is larger than that of a free jet, so is the faster decay of jet centerline velocity, Fourth, in ZSI the jet flow is nonsimilar and high turbulent intensities were found. The vertical turbule nt jet transforms into two opposite horizontal surface jets after the impin gement. And finally, the maximum velocity of the horizontal surface jet in ZHJ decays according to a power law.