Concept Design of a Large Water Tunnel*

 

Large-scale water tunnels are valuable for studying meso-scale models with turbulent unit Reynolds number. However, building  water tunnels presents significant financial and engineering challenges. This study discusses the concept design process for a medium-speed, large-scale water tunnel with low inlet turbulence and interchangeable fully enclosed and free surface test sections. The tunnel is proposed to achieve free-stream flow speeds of 3-4 m/s through a 1 x 1 meter test section that can be converted into a free-surface test section. The design is motivated by the need to test multi-phase fluid-structure interactions with good optical access and long testing durations.  In this presentation, we will discuss the design process behind the proposed tunnel. Ansys CFX was employed to simulate fluid flow within the tunnel, playing a crucial role in refining the design and optimizing flow dynamics. Our simulations highlighted the occurrence of undular wave phenomena, which we analyzed using semi-empirical models of near-critical free-surface flows to improve the tunnel's performance when operating with a free surface. The outcomes of this research will provide significant insights into the design and operation of high-speed water tunnels, offering a cost-effective and versatile solution for advanced hydrodynamic testing.