Abstract
On the basis of Morison’s empirical formula and modal separation method in estimating the force and torque exerted by internal solitary waves (ISWs) on a cylindrical pile, it is found that the loads exerted by the ISWs change largely in different seasons at the same site of the continental shelf in the South China Sea (SCS) even under the condition that the amplitudes of ISWs are the same. Thus, the effect of a seasonal water stratification variation on the force and torque exerted by the ISWs is investigated, and a three-parameter stratification model is employed. It is shown that the loads exerted by the ISWs depend largely on the water stratification. The stronger the water stratification, the larger the force and the torque; when the depth where the maximum thermocline appears is deepened, the force decreases but the torque increases; when the width of the thermocline is narrowed, the force increases but the torque decreases. The seasonal variation of the force and the torque exerted by the ISWs in four seasons in the SCS is thus explained.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Apel J R, Ostrovsky L A, Stepanyants Y A. 1995. Internal solitons in the ocean. The Journal of the Acoustical Society of America, 98(5): 2863–2864
Cai Shuqun, Long Xiaomin, Gan Zijun. 2003. A method to estimate the forces exerted by internal solitons on cylindrical piles. Ocean Eng, 30: 673–689
Cai Shuqun, Long Xiaomin, Wang Shengan. 2008. Forces and torques exerted by internal solitons in shear flows on cylindrical piles. Appl Ocean Res, 30: 72–77
Cai Shuqun, Wang Shengan, Long Xiaomin. 2006. A simple estimation of the force exerted by internal solitons on cylindrical piles. Ocean Eng, 33: 974–980
Ebbesmeyer C, Coomes C A, Hamilton R, et al. 1991. New observations on internal waves (solitons) in the South China Sea using an acoustic Doppler current profiler. Marine Tech Soc, 91: 165–175
Gill A E. 1982. Atmosphere-Ocean Dynamics. New York: Academic Press
Guo Haiyan, Zhang Li, Li Xiaomin, et al. 2013. Dynamic responses of top tensioned riser under combined excitation of internal solitary wave, surface wave and vessel motion. Journal of Ocean university of China, 12: 6–12
Grimshaw R, Pelinovsky E, Talipova T. 2007. Modeling internal solitary waves in the coastal ocean. Surv Geophys, 28: 273–298
Lighthill M J. 1986. Fundamentals concerning wave loadings on offshore structures. J Fluid Mechanics, 173: 667–681
Liu A K, Ramp S R, Zhao Y, et al. 2004. A case study of internal solitary wave propagation during ASIAEX 2001. IEEE Journal of Oceanic Engineering, 29: 1144–1156
Morison J R, Johnson J W, Schaaf S A, et al. 1950. The forces exerted by surface waves on piles. Journal of Petroleum Technology, 2(5): 149–154
Pan Jiayi, Jay D A, Orton P M. 2007. Analyses of internal solitary waves generated at the Columbia River plume front using SAR imagery. J Geophys Res, 112: C07014
Si Zongshang, Zhang Yuanling, Fan Zhisong. 2012. A numerical simulation of shear forces and torques exerted by largeamplitude internal solitary waves on a rigid pile in South China Sea. Appl Ocean Res, 37: 127–132
Song Zhijun, Teng Bin, Gou Ying, et al. 2011. Comparisons of internal solitary wave and surface wave actions on marine structures and their responses. Appl Ocean Res, 33(2): 120–129
Xie Jieshuo, Xu Jiexin, Cai Shuqun. 2011. A numerical study of the load on cylindrical piles exerted by internal solitary waves. J Fluids and Structures, 27: 1252–1261
Zha Guozhen, He Yijun, Yu Tan, et al. 2012. The force exerted on a cylindrical pile by ocean internal waves derived from nautical Xband radar observations and in-situ buoyancy frequency data. Ocean Eng, 41: 13–20
Zheng Quanan, Susanto R D, Ho C R, et al. 2007. Statistical and dynamical analyses of generation mechanisms of solitary internal waves in the northern South China Sea. J Geophys Res, 112: C03021
Author information
Authors and Affiliations
Corresponding author
Additional information
Foundation item: The Strategic Priority Research Program of the Chinese Academy of Sciences under contract No. XDA11020201; the National Basic Research Program of China under contract Nos 2011CB013701 and 2013CB956101; the National Natural Science Foundation of China (NSFC) under contract No. 41025019; the Knowledge Innovation Program of the Chinese Academy of Sciences under contract No. SQ201302; LTO Independent Research Program under contract No. LTOZZ1304.
Rights and permissions
About this article
Cite this article
Cai, S., Xu, J., Chen, Z. et al. The effect of a seasonal stratification variation on the load exerted by internal solitary waves on a cylindrical pile. Acta Oceanol. Sin. 33, 21–26 (2014). https://doi.org/10.1007/s13131-014-0468-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13131-014-0468-8