Hydrodynamic Design Considerations for Hydroacoustic Facilities: Part I—Flow Quality

Abstract

Design studies are described for two recently completed large scale hydroacoustic test facilities (one of which is the world’s largest). These recirculating water tunnels have a different configuration than conventional tunnels, and special hydrodynamic design studies were required to evaluate and optimize the performance of some critical components. This paper considers the flow quality in the test section as influenced by the design of the contraction and the turbulence management system. Numerical modeling and experimental work were used to arrive at an acceptable nonsymmetrical nozzle design. Studies were also made of a turbulence management system using honeycombs rather than screens as typically used. Although design goals for turbulence levels were met, this study indicated that additional research in the area of turbulence management is necessary before there is a complete understanding of the overall process of turbulence attenuation.

Development of measurement methods for testing of hydrokinetic devices to evaluate the environmental effect on local substrate

“…Additionally, the contraction inlet should be designed to limit flow separation at the entrance by having a smooth bell-mouthed entry which will suppress turbulence and ultimately reduce velocity non-uniformity throughout the device (Walmsley 1999). The magnitude of the pressure and the spatial gradient of pressure through the contraction, if immoderate, will yield boundary layer separation (Wetzel & Arndt 1994). The nozzle insert helps to accelerate the flow and create velocities similar to that of a river environment.…”

The singing vortex

“…Thus span to tunnel size was held constant for the two series of experiments. Oil flow visualizations were obtained in two wind tunnels, one at the Department of Aerospace Engineering at the University of Minnesota [30] and the second at SAFL (originally an air model of the HYKAT facility, [31,32]). …”

Stereoscopic PIV of Steady Flow Through a Bileaflet Mechanical Heart Valve

“…The contraction profile was a 5 th order polynomial employed successfully in low speed wind and water tunnel applications (Brassard and Ferchichi 2005, Wetzel and Arndt 1994, Bell and Mehta 1988 …”