DISPERSION PROCESS IN PRISMATIC CHANNELS - CIRCULAR PIPES WITH PARTIAL FILLING.

One of the main tasks of water management is to achieve good water quality. Important auxiliary tools in this case are mathematical models that currently are incorporated in almost every numerical model, used to solve problems in everyday practice of water management and engineering. A dispersion coefficient is one of the crucial input parameters of transport processes. The paper is focused on determination of dispersion coefficients in sewers, as in prismatic and straight stream channel with relatively constant roughness of streambed. Field experiments were performed in a straight sewer sections under dry weather flow conditions, i.e. with relatively low pipe filling, discharges and velocities. Consequently, the dispersion coefficient in a sewer line with various direction changes was determined. In the end of the paper the observed effect of "dead zones" is described, which theoretically should not occur in conditions of our experiment (prismatic channel with no obstacles). Paper also discuss this topic and explain its root cause. [ABSTRACT FROM AUTHOR]