on the Coasts, Ports and Marine Structures ICOPMAS "98"

Numerical modellings have been widely used to predict the turbulent mixing and turbulent transport of pollutant in coastal waters. Numerical modellings are usually restricted to model sizes, hence it is impossible to include all factors which can influence theiturbulent mixing. It has been observed in many cases that the calculated data differ considerably from those obtained experimentally and the aim of the present paperis to demonstrate this disagreement, by conducting a series of field measurements in the east coastal waters of England. A solution of fluoroscein dye was poured onto the water surface at two sites. The development of the dye patches and its mixing were determined by sampling the dye concentration at lm below the water surface at regular intervals. In addition the mean velocity profiles were measured at hourly intervals. The results disclose that these profiles are logarithmic, irrespective of the stste of tidal currens.