Experimental Design Studies on Free-jet Water Tunnels

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Experimental Design Studies on Free-jet Water Tunnels

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St. Anthony Falls Hydraulic Laboratory




A study of the design and operating characteristics of free-jet water tunnels is presented. Included is a brief analysis indicating that this type of water tunnel is particularly well suited for the empirical analysis of steady-state cavities which form about solid bodies moving through water at extremely low cavitation indices. It is pointed out that the conventional closed-jet and open-jet types possess inherent limitations on the quality of the test-section flow and the accuracy and applicability of the measurable flow properties at these low cavitation indices. The experimental apparatus is described verbally and photographically. It was designed for the production and study of a test jet of circular cross section having a 2-in. diameter and an effective length of 6 diameters. The jet could be directed vertically upward, vertically downward, and horizontally. Facilities for the production and analysis of steady state cavities within the jet are also described. The experimental studies and the results are discussed. Included are observations concerning air entrainment by the jet, visual qualities of the jet, total head Pitot tube traverses of the jet, and steady~state cavities within the jet at cavitation indices as low as 0.015. The report concludes with general recommendations concerning the design of free-jet water tunnels.



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Prepared for Office of Naval Research, Department of the Navy Under Office of naval Research Contract N8onr-66202

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Christopherson, Charles D.. (1951). Experimental Design Studies on Free-jet Water Tunnels. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/108131.

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