Shear dispersion in the surface layers of the sea.

摘要: The kinetic energy density, k, and lifetime, t, of a turbulent eddy, volume V, are shown to be related a characteristic length scale, 2, by: 13 =vk= c2/3e2/3 t-C 1/312/3 where c is the dissipation rate. A self similar cascade of discrete eddy sizes derived, each size next larger by: P 22 CC i+l i where C= 81'2. With some simple assumptions as turbulent production process mean logarithmic velocity profile is derived. relationship between friction and Reynolds stress explained in terms large eddy intermittency, n. Below a critical free stream velocity, U', n is proportional velocity. rate, e, is then constant given by: e U'3/N3L where N number discrete boundary layer. When boundary layer has reached surface N- 11. The observed turbulent spectral characteristics derived from the eddy equations without using dimensional reasoning an explanation mechanism behind similarity scaling proposed. An experiment was carried out North Sea test the model predictions. Correlations showed that, except at slack water, largest eddies were approximately cubic, occupying the whole flow depth, advected with flow. Frequency spectra provided evidence that formulation was correct. intermittency proportional the current speed value c, calculated by several methods, was found value: C=0.3 cm2/s3 The isolated using a cropping technique plotted phase portrait of the strange attractor. This demonstrated the boundary sat preferred, levels. The levels observed could discete model. A computer code based on model tested against a series scale oil dye releases Sea. intermittency, meandering, dispersion well simulated above.