Feasibility Study of a Hydrodynamic Test Facility at the Detroit Dam

Abstract

In considering the technology necessary to develop ships in the 70 to 100 knot range, it becomes evident that some form of drag reduction will be necessary to achieve this goal. Several viable drag reduction techniques have been studied for many years. These include surface striations, polymer injection and micro-bubble injection. The latter technique shows great promise with drag reduction of about 80% having been demonstrated. In order to adapt a drag reduction concept in the fleet, it is essential that studies be made that simulate, as closely as possible, prototype conditions. This leads to the need for a test facility that can achieve flow velocities in the 70-knot range. At present there are no hydrodynamic test facilities that fall in this category. However there is an existing Corps of Engineers test facility that could be adapted and modified to suit the Navy’s test requirements. This facility is located at the Detroit Dam and Lake on the North Santiam River near Detroit, Oregon. This is a multipurpose facility designed for flood control, navigation, irrigation and power. A powerhouse is situated at the base of the dam that has two 50 MW units installed. In addition to the two penstocks for power production, there is an additional, gated bottom outlet that supplies water to an eight-foot diameter penstock. A rudimentary flume is fitted to the outlet this penstock that discharges directly into the tailwater of the plant. At high water elevation, approximately 320 feet of head is available at the test site. In the absence of losses this equates to a maximum velocity of 83 knots. Maximum head is available for about 4 to 5 months out of the year. The conduit has not been used for over 20 years, and very little information regarding its performance is available. The conduit consists of an 8 ft diameter steel pipe with its intake located about 225 ft below the summer water level and its exit 320 ft below the summer water level. The winter reservoir level is about 115 ft lower. A small rectangular test section has been attached to the exit of the 8 ft diameter pipe about 25 years ago. It was used for a particular purpose and abandoned after the work was completed. It is assumed that this section has no further use, and is subject to removal. It is the purpose of the present investigation to determine the hydrodynamic capabilities of such a facility. Preliminary results of the study are summarized in the following sections.