Oscillatory loads on circular cylinder with secondary structures. (April 2020)

• Record Type: Journal Article
• Authors: Petersen, Thor Ugelvig; Mandviwalla, Xerxes; Christensen, Erik Damgaard; Tarp-Johansen, Niels Jacob; Rüdinger, Finn
• Is Part Of: Journal of fluids and structures. Volume 94(2019)
• Publication Date: 2020-04
• Subjects: Fluid-structure interaction -- Periodicals; Fluid mechanics -- Periodicals; Structural dynamics -- Periodicals; Structural analysis (Engineering) -- Periodicals; 620.106
• DOI: 10.1016/j.jfluidstructs.2020.102935
• Languages: English
• ISSNs: 0889-9746

Abstract

Abstract: This study deals with a numerical and experimental study of the secondary structures effect on the load on the main circular cylinder. Its objective is to address the increasing amount of offshore structures installed as part of offshore wind farms. The typical support structure for a wind turbine is a monopile foundation. Boat-landings are attached to the monopile and these structures act as secondary structures. Forces on a cylinder with and without secondary structures attached in unsteady flows have been measured experimentally and simulated numerically. The results of the tests were compared to each other and to existing work in the present report for validation of the CFD model. The secondary structures were represented by circular cylinders placed at different orientations around the main circular cylinder. All the analyses assumed uniform conditions transverse to the flow direction (i.e. 2D set-up). The numerical simulations were based on the OpenFOAM CFD tools. The validation tests with a circular cylinder without secondary structures showed good agreement between the physical and numerical results, as well as to the results available in the open literature. The orientation of the secondary structures had a clear influence on the drag related part of the force as the drag coefficient C D when the secondary structure was orientated towards θ = 90°, i.e. perpendicular to the flow direction. The inertia part of the force, i.e. the inertia force coefficient C M, was only affected by the orientation to small extend.