An investigation of the effects of ground wind on natural frequency of pipe-lines

Abstract

The wind induced vibration of a pipe-line in a vertical plane is investigated. The alternating lift force imposed on a pipe-line is apparenty dependent not only on wind velocity and pipe size, but its frequency and magnitude are dependent on amplitude response of the pipe. Since the total problem is not amenable to ordinary methods of analysis, investigation is made of several situations, that is, with the lift force uniformly distributed along the pipe and with the lift force magnitude varying with vibration amplitude. The results of these cases are compared with and without internal fluid flow. In addition, an investigation is made to reveal elements in the nature of the problem pointing the way to observed behavior of pipe-lines. The resulting expression, while not presented as a complete solution, does indicate the fact that shifting of resonance conditions due to lift force magnitude and frequency will produce alternating periods of large and small amplitude conditions roughly similar to beating.