A cluster of flexible obstacles under the influence of a turbulent boundary layer is widely encountered in environmental and industrial fluid mechanics: atmospheric boundary layers over patches of forest and cities or wind farms, river and sea flows over vegetated beds, currents impinging offshore structures and tidal turbines, flows through heat exchangers and hull barnacles. This project aims to clarify the role of the cluster morphology and flexibility by means of an extensive experimental investigation targeted to high accuracy drag assessment and wake characterization. The project will involve three different facilities of the University of Southampton: the wind tunnel, the water channel and the 138 m long towing-tank.

The prediction of the forces is crucial to evaluate the effective power harvested and to provide the basis for a safer structural design and for preventing damages. The mutual behaviour of flow and obstacles together with the wake structure, however, govern the transport of heat and mass in ecologically-relevant phenomena, typical examples are: the carbon dioxide exchange, the sediment resuspension in rivers or sea, the nutrient uptake process.

Bharath Ganapathisubramani's

Experimental Fluid Mechanics

Research Laboratory

Flow past flexible cluster of obstacles

Figure: Visualisation of flexible cluster of objects

Claudia Nicolai, Bharath Ganapathisubramani