Design of a Recirculating Water Tunnel for the Study of High-Reynolds Number Turbulent Boundary Layers

This paper reports on the design and fabrication of a high-Reynolds number recirculating water tunnel, which will be used primarily for the study of turbulent boundary layers with an emphasis on drag reduction applications. The primary design specifications were (i) achieve a momentum thickness based Reynolds number above 10,000, (ii) maximize optical access, and (iii) minimize flow non-uniformity. This paper discusses the design considerations and procedures to meet each of these design criteria as well as the manufacturing of the components, installation, and design of auxiliary systems such as the pressure regulation system. There are several recirculating water tunnels at universities that can achieve comparable Reynolds numbers, but they were either built with at least double the budget of the current project or are refurbished tunnels from other laboratories (i.e. key design considerations were already fixed). Thus, the current work offers a guide for the overall design of a low-cost, high-Reynolds number water tunnel. A brief review of other recirculating high-Reynolds number water tunnels is included. Currently, installation has begun with the fabrication complete.