Experimental investigation of hydrodynamic loading induced by regular, steep non-breaking and breaking focused waves on a fixed and moving cylinder

authored by

Shaswat Saincher, V. Sriram, Shagun Agarwal, T. Schlurmann

Abstract

Monopiles are commonly adopted in marine structures and subject to combined loading from waves and currents. The nature of superposition of wave and current loads needs to be known during the design stage. In the present paper, combined hydrodynamic loading induced by nonlinear waves and uniform currents on a cylinder is experimentally investigated. The current is represented by towing the cylinder along the flume. By this, nonlinear wave–current interactions are excluded physically, but the loading of a proportional current following or opposing a wave group is captured and analyzed. It is argued that towing makes provision for analyzing the nature of superposition of wave and current loads using Morison theory (which is not applicable to true combined wave–current fields) and also facilitates experimentation of a wide range of nonlinear wave and uniform current loading combinations onto the structure. Accordingly, regular, steep non-breaking and breaking focused waves interacting with the cylinder towed along and in opposition to the wave-field at different speeds have been investigated. The non-breaking wave–structure interactions have been analyzed within the framework of Morison theory using Fully Nonlinear Potential Theory (FNPT) based kinematics. Breaking wave–cylinder interactions have been analyzed through a spectral approach. The experiments demonstrate that wave and locally-acting current loads on the structure can be linearly superimposed, irrespective of the nature of waves and towing speed. Hence, provided wave–current interactions are excluded, steep breaking wave and uniform current loads can be linearly superimposed, despite focused wave generation itself being inherently nonlinear.

Organisation(s)

Ludwig-Franzius-Institute of Hydraulics, Estuarine and Coastal Engineering

External Organisation(s)

Indian Institute of Technology Madras (IITM)

Type

Article

Journal

European Journal of Mechanics, B/Fluids

Volume

93

Pages

42-64

No. of pages

23

ISSN

0997-7546

Publication date

01.05.2022

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Mathematical Physics, General Physics and Astronomy

Sustainable Development Goals

SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.1016/j.euromechflu.2021.12.009 (Access: Closed)