Author(s): Donatella Termini
Linked Author(s): Donatella Termini
Keywords: No Keywords
Abstract: Mussels are defined as “ecosystem engineers” capable of affecting the hydrodynamics, passively and actively (Navaratnam et al., 2018; Termini et al., 2023). The generation of larger-scale turbulence around the mussels living on the river bed may also affect the quality of the habitat. Thus, it is extremely important to know the effects determined by the presence of mussels on flow characteristics. In the present study, preliminary results on flow and turbulence characteristics around an isolated mussel over a gravel-bed are reported. The presence of a mussel enhances the effects determined by the rough-bed on the kinematic characteristics of flow. The analysis is performed based on data collected in a straight laboratory gravel-bed flume both in the absence and presence of an isolated and partially buried mussel (Unio elongatulus), aligned with the incoming flow. In order to take into account spatial heterogeneities, the double-averaged velocities are considered for the analysis in the absence of a mussel on the bed. Results show that, because of the presence of gravels, in the absence of the mussel, the streamwise velocity profiles show an inflection point with the formation of a mixing layer whose thickness varies passing from the banks to the channel axis. The presence of a mussel modifies the shape of the velocity profile with the formation of turbulent flow structures around it. Different effects on the velocity and turbulence fields have been identified in relation to the mussel’s filtering capacity.
Year: 2024