Numerical Simulation of Flow Patterns and Mass Exchange Processes in Dead Zones

Contaminants and nutrients transport in streams and rivers is significantlyaffected by the presence of dead zones that are due to geometrical irregularities, that mayhave both natural and anthropic origins. Dead zones are characterized by mean flowvelocity in the main stream direction approximately equal to zero and by exchangeprocesses of solutes with the main stream. This paper presents the preliminary results of anumerical study undertaken to investigate the fundamental flow phenomena around andinside a simplified geometry, representative of flow in natural rivers with dead zones.Exchange rates between the dead zone and the channel were calculated resulting in a goodagreement with previous literature experimental values for the same geometry.