Model Studies of Apra Harbor, Guam, M.I. Progress Report for June, 1948

Abstract

Studies of induced currents were the main activity of the month. Preliminary frequency response studies were started and detailed marigram analysis was resumed. Studies of induced currents involved development of methods, running of tests and analysis of data. Some currents are induced in the harbor by the waves which pass through the entrance. These were the currents studied. They give basic data. Tidal changes and outer ocean currents will be superposed later to learn of composite effects. Frequency response studies were initiated this month also. The present wave machines were designed to make such tests possible, since both amplitude and frequency of the wave trains can be controlled over wide ranges. It is intended to run tests through the entire spectrum after observing and measuring the effects of certain calculated frequencies. The calculated frequencies were the fundamentals and harmonics of each division of the harbor. Marigram analysis was resumed along the lines of the program previously decided upon, i.e. computation and plotting of residual mass curves between adjacent stations. These curves reveal the duration and rate of flow which could obtain through the proposed pollution channels. Modification to the oscillograph was made to reduce the tape speed, the range in speeds being broadened accordingly. Component parts of the wave height averaging device are being assembled as received.