INSTABILITY OF FLOW IN OPEN CHANNELS PARTIALLY COVERED WITH VEGETATION

Abstract

Linear stability analysis of a turbulent flow in a wide rectangular open channel partially covered with vegetation is performed using a shallow-water approach. The vegetated and non-vegetated zones are configured so that violent transverse mixing occurs at the vicinity of the interface between the two zones. In the base state there is no transverse velocity, although there is an abrupt variation in the streamwise velocity near the interface between the non-vegetated and the vegetated zones. The perturbations were analysed in order to find their maximum growth rate. Results show that depending on the assumed wavenumber, the maximum growth rate of perturbations is positive, what means that the perturbations may grow as time progresses.