Numerical study of nonlinear shear instability of longshore currents

Shen Liangduo; Zou Zhili; Tang Zhibo; Ni Yunlin; Chen Wei

doi:10.3969/j.issn.0253-4193.2017.07.003

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Shen Liangduo, Zou Zhili, Tang Zhibo, Ni Yunlin, Chen Wei. Numerical study of nonlinear shear instability of longshore currents[J]. Haiyang Xuebao, 2017, 39(7): 26-35. doi: 10.3969/j.issn.0253-4193.2017.07.003

Citation:

Shen Liangduo, Zou Zhili, Tang Zhibo, Ni Yunlin, Chen Wei. Numerical study of nonlinear shear instability of longshore currents[J]. Haiyang Xuebao, 2017, 39(7): 26-35. doi: 10.3969/j.issn.0253-4193.2017.07.003

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Numerical study of nonlinear shear instability of longshore currents

doi: 10.3969/j.issn.0253-4193.2017.07.003

1.
School of Maritime and Civil Engineering, Zhejiang Ocean University, Zhoushan 316022, China
2.
State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian 116024, China

Received Date: 2016-08-17
Rev Recd Date: 2017-02-05

Abstract

Abstract

It is necessary to analyze the characteristics of longshore current instability by using the nonlinear instability model when wave height reaches a finite amplitude. Building and verifying the nonlinear instability mathematical model of longshore current, this paper discusses the influences of model parameters and obtains the value of model parameters corresponding to the experimental result. The development process and its characteristics of longshore current instability in experiment are simulated and illustrated by the mathematical model. Key innovations include:(1) the smaller the bottom friction coefficient and lateral mixing coefficient, the sooner the instability occurrence, the bigger the fluctuation amplitude is; (2) the evolution processes of longshore current include five stages (linear, double period, larger period, wave group and irregular stages). The longshore current instability in the experiment occurs in stages of linear or double period. The vortex in double period stage forms by the vortexes in the linear stage which catch, match and merge one another. The match of vortex occurs in collision, the major energy transfers to trace wave and spreads along the coast at a slower rate of vortex.
- nonlinear shear instability,
- nonlinear,
- instability,
- longshore current instability,
- longshore current

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References(17)

References

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