Application of Tesla Valve to Bidirectional Open-Channel Flows

Abstract

Dams hinder water circulation and consequently disrupt the river continuum which adversely affects aquatic organisms and degrades water quality. An alternative new concept for a dam has been proposed with an optimal design that prevents seawater from flowing upstream while maintaining the continuity of the river–estuary ecosystem. A Tesla valve was used because its asymmetric geometry increases the flow resistance only in a single direction. The numerical model setup aimed to simulate wave-induced open-channel flows in OpenFOAM using the volume of fluid method and investigate the capability of the channel design to enhance the asymmetric flow resistance, and the model was validated by laboratory experiments. Various combinations, scales, shapes, and arrangements of the structures were considered for deployment. Subsequently, these designs were evaluated based on the difference in flow discharges in each flow direction. The optimal choice included a 30° angle between the sidewalls and the structures, and streamwise spacing between the structures at 5/3 times the channel width. Further, longer main structures with substructures and a slightly offset design can help increase the flow asymmetry in bidirectional open-channel flows. Although the present study has limitations in terms of methodology and complex structural factors, the proposed design suggests the basic design of a new concept for Tesla valve-like geometry.