Numerical Study on the 3-D Complex Characteristics of Flow Around the Hull Structure of TLP

• Published in: China ocean engineering Vol. 29; no. 4; pp. 535 - 550
• Main Author: 谷家扬 朱新耀 杨建民 卢燕祥 肖龙飞
• Format: Journal Article
• Language: English
• Published: Nanjing Chinese Ocean Engineering Society 01.06.2015
• Subjects: Coastal Sciences; Engineering; Fluid- and Aerodynamics; Marine & Freshwater Sciences; Navier-Stokes方程; Numerical and Computational Physics; Oceanography; Offshore Engineering; Simulation; Strouhal数; TLP; 张力腿平台; 数值研究; 流动特性; 电流方向; 船体结构; TLP; vorticity ISO surface; flow characteristic; hydrodynamic coefficient; Strouhal number
• ISSN: 0890-5487; 2191-8945
• DOI: 10.1007/s13344-015-0037-8

Vortex-induced motion is based on the complex characteristics of the flow around the tension leg platform （TLP） hull. By considering the flow field of the South China Sea and the configuration of the platform, three typical flow velocities and three flow directions are chosen to study the numerical simulation of the flow field characteristics around the TLP hull. Reynolds-averaged Navier-Stokes equations combined with the detached eddy simulation turbulence model are employed in the numerical study. The hydrodynamic coefficients of columns and pontoons, the total drag and lift coefficients of the TLP, the formation and development of the wake, and the vorticity iso-surfaces for different inlet velocities and current directions are discussed in this paper. The average value of the drag coefficient of the upstream columns is considerably larger than that of the downstream columns in the inlet direction of 0°. Although the time history of the lift coefficient demonstrates a ＂beating＂ behavior, the plot shows regularity in general. The Strouhal number decreases as the inlet velocity increases from the power spectral density plot at different flow velocities. The mean root values of the lift and drag coefficients of the front column decrease as the current direction increases. Under the symmetrical configuration of 45°, the streamwise force on C4 is the smallest, whereas the transverse force is the largest. The broken vortex conditions in current directions of 22.5° and 45° are more serious than that in the current direction of 0°. In addition, turbulence at the bottom of the TLP becomes stronger when the current direction changes from 0° to 45°. However, a high inlet velocity indicates a large region influenced by the broken vortex and shows the emergence of the wake behind the TLP under the same current angle.