Session: 08-03-01 Risers, Pipelines & VIV- I

Paper Number: 124959

124959 - Impacts of Small Gaps and Buried Depths on Forces of a Circular Cylinder Near a Plane Wall 

Numerical simulations of a cylinder placed on or near a plane wall are often required in engineering design of offshore structures to determine hydrodynamic forces, such as a power cable laid directly on the seabed. Generation of computational mesh around such a configuration has been a challenge of conducting such simulations, primarily due to the narrow gaps formed between the cylinder and the plane wall. Extremely fine meshes are often required in the region around the narrow gaps to achieve reliable numerical results, leading to additional computational costs. This study aims at developing a computational strategy to alleviate this problem. To this end, a series of direct numerical simulations (DNS) are conducted at a constant Reynolds number 3900 for following three geometric configurations: (1) the cylinder is shallowly embedded in the plan wall; (2) the cylinder is placed slightly above the wall with the gap between the cylinder and the wall sealed by thin plate and (3) the cylinder is placed above the wall with the gap open to allow the flow passing through. The computational meshing of above simulations presents a less challenge than that would otherwise be needed for a cylinder placed on the wall. The possibility of employing one of the above geometric configurations to determine the hydrodynamic forces on a cylinder placed on the wall is examined in this study. The applicability of the proposed modelling strategy to a wide range of Reynolds number is discussed, based on the present results and published data in literature.

Presenting Author: Zinan Liu South China University of Technology

Presenting Author Biography: Zinan Liu is a PhD student in School of Marine Science and Engineering at South China University of Technology (SCUT), China, supervised by Prof. Liang Cheng, Dr. Feifei Tong and Dr. Chengjiao Ren. Zinan Liu got her Bachelor degree in Harbor, Waterway and Coastal Engineering at Dalian University of Technology (DUT), China in 2018. And she got her Master degree in Civil Engineering at DUT in 2021. From 2022-2023, Zinan Liu worked as a research assistant in SCUT and started her PhD topic. Her research experience includes Computational Fluid Dynamics (CFD) and hydrodynamics of cylindrical structures in a trench / on a plane wall under steady current .

Authors:

Zinan Liu South China University of Technology
Liang Cheng South China University of Technology
Chengjiao Ren The University of Western Australia
Feifei Tong Southern Cross University