Oscillation of a Flexible Catenary Shaped Submersed Pipe Induced by Two-Phase Slug Flow of Liquid and Gas

In this paper, an experimental study of the excitation of a submersed suspended flexible pipe induced by the internal two-phase slug flow of liquid and gas is presented. The experiment was conducted with the pipe set in catenary configuration inside a water tank with a depth of 2m. Water and air were injected into the pipe at various flow rates combinations, leading to the formation of horizontal slug flow patterns. The slug two-phase flow generated intermittent loads on the pipe causing its oscillation. The dynamic response of the pipe to the slug flow was monitored by cameras which registered the movement of target marks set up along the body of the pipe. Processing the video images, we obtained the time-history of the movement of the pipe, and from this, the frequencies and amplitudes of motion were determined. With the proper scaling up, and in conjunction with computer simulators of pipe dynamics running intermittent load models of slug flows, the present work may be helpful to improve the capability of engineers for the analysis of the behavior of suspended risers used in offshore petroleum production carrying up oil and gas from petroleum reservoir wells to floating production facilities.