Accession Number : AD0475359
Title : WULLENWEBBER ANTENNA VIBRATION STUDY.
Descriptive Note : Master's thesis,
Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA
Personal Author(s) : Breckon, Richard L. ; Hite, Philip R.
Report Date : 1965
Pagination or Media Count : 67
Abstract : The U. S. Navy is completing a world-wide radio directional antenna system, which has exhibited an undesirable wind induced oscillation of one of the primary structural members, resulting in physical damage and failure. Oscillations at some installations have been estimated at six cycles per second, and with amplitudes of plus or minus two feet. A dynamic wind tunnel model was designed, fabricated and tested, with the purpose of simulating the response of the various antenna designs. The installation at Winter Harbor, Maine, a two foot cylinder with one inch flanges at 90 degrees from the stagnation points, was investigated. These tests prove that, as a result of the flanges, the oscillation frequency is a function of wind velocity, so that the Strouhal number remains constant at 0.17. It is also shown that the structure's natural frequency has negligible effect upon response. As an in the field modification, it is recommended that the beams be rotated 90 degrees about their longitudinal axes, which should reduce the amplitude of vibration by a factor of about six. (Author)
Descriptors : (*ANTENNAS, VIBRATION), WIND, OSCILLATION, WIND TUNNEL MODELS, MODEL TESTS, SIMULATION, RESPONSE, ROTATION.
Subject Categories : Electrical and Electronic Equipment
Distribution Statement : APPROVED FOR PUBLIC RELEASE