Using the data of beach face high oscillations and waves and flows of the surf zones influenced by the swells, the characteristics including beach face variation trends, trend shapes, oscillation periods, oscillation ...Using the data of beach face high oscillations and waves and flows of the surf zones influenced by the swells, the characteristics including beach face variation trends, trend shapes, oscillation periods, oscillation intensions of different profile shapes, and the characteristic relations between different stake points on the same profile were analyzed comparatively. The relations between the beach face with high oscillations erosion and sediment and the surf zone infragravity waves were also analyzed based on the cress spectrum analysis. The results showed that the swash diffluences caused by the beach cusp rhythm topography hasten the sediment transport from the beach ridge to beach paddy, and the beach face of the swash zones has the infragravity periodic oscillations, and the oscillation intensions descend from the bottom to the top of the beach face, and the infragravity waves of the surf zones have significant effect on the high-frequency variations of erosion and sediment of the beach face.展开更多
This paper presents a novel numerical model using a fully three-dimensional(3D),incompressible,two-phase flow NavierStokes(NS)solver,which are discretized by the finite volume method.A high-resolution STACS-VOF method...This paper presents a novel numerical model using a fully three-dimensional(3D),incompressible,two-phase flow NavierStokes(NS)solver,which are discretized by the finite volume method.A high-resolution STACS-VOF method is used to capture the interface between the air and water phases.The validity of the simulation following this model is examined through3D shear flow and collapsing cylinder of water.Then,this proposed model is adopted to simulate the dynamics of flow involved with surge bore propagating over a slope in the swash zone.The computed uprush shoreline motion and the tip of runup water surface agreed well with experimental data,which indicates that this model can describe the aerated flow accurately.Numerical analyses are also applied to the spatial and temporal distributions of free-surface,instantaneous flow field,and maximal bed shear stress in the bore collapse,uprush and backwash processes.The results from the analyses reveal that the flow dynamics is complicated after the bore breaks,and the proposed model can well capture the structure characteristics of sheet flow,which are better than the previous results.All these findings are of help to understand the pattern of sediment transport and coastal evolution in the swash zone.展开更多
A physical parameter, fib, which was used to meet the forcing of primary short waves to be off-resonant before wave breaking, has been considered as an applicable parameter in the infra-gravity wave generation. Since ...A physical parameter, fib, which was used to meet the forcing of primary short waves to be off-resonant before wave breaking, has been considered as an applicable parameter in the infra-gravity wave generation. Since a series of modulating wave groups for different wave conditions are perfonned to proceed with the resonant mechanism of infra- gravity waves prior to wave breaking, the amplitude growth of incident bound long wave is assumed to be simply controlled by the normalized bed slope, fib. The results appear a large dependence of the growth rate, a, of incident bound long wave, separated by the three-array method, on the normalized bed slope, fib. High spatial resolution of wave records enables identification of the cross-correlation between squared short-wave envelopes and infra-gravity waves. The cross- shore structure of infra-gravity waves over beaches presents the mechanics of incident bound- and outgoing free long waves with the formation of free standing long waves in the nearshore region. The wave run-up and amplification of infra-gravity waves in the swash zone appear that the additional long waves generated by the breaking process would modify the cross-shore structure of free standing long waves. Finally, this paper would further discuss the contribution of long wave breaking and bottom friction to the energy dissipation of infra-gravity waves based on different slope conditions.展开更多
文摘Using the data of beach face high oscillations and waves and flows of the surf zones influenced by the swells, the characteristics including beach face variation trends, trend shapes, oscillation periods, oscillation intensions of different profile shapes, and the characteristic relations between different stake points on the same profile were analyzed comparatively. The relations between the beach face with high oscillations erosion and sediment and the surf zone infragravity waves were also analyzed based on the cress spectrum analysis. The results showed that the swash diffluences caused by the beach cusp rhythm topography hasten the sediment transport from the beach ridge to beach paddy, and the beach face of the swash zones has the infragravity periodic oscillations, and the oscillation intensions descend from the bottom to the top of the beach face, and the infragravity waves of the surf zones have significant effect on the high-frequency variations of erosion and sediment of the beach face.
基金supported by the National Natural Science Foundation of China(Grant Nos.51239001,51179015,41176072)
文摘This paper presents a novel numerical model using a fully three-dimensional(3D),incompressible,two-phase flow NavierStokes(NS)solver,which are discretized by the finite volume method.A high-resolution STACS-VOF method is used to capture the interface between the air and water phases.The validity of the simulation following this model is examined through3D shear flow and collapsing cylinder of water.Then,this proposed model is adopted to simulate the dynamics of flow involved with surge bore propagating over a slope in the swash zone.The computed uprush shoreline motion and the tip of runup water surface agreed well with experimental data,which indicates that this model can describe the aerated flow accurately.Numerical analyses are also applied to the spatial and temporal distributions of free-surface,instantaneous flow field,and maximal bed shear stress in the bore collapse,uprush and backwash processes.The results from the analyses reveal that the flow dynamics is complicated after the bore breaks,and the proposed model can well capture the structure characteristics of sheet flow,which are better than the previous results.All these findings are of help to understand the pattern of sediment transport and coastal evolution in the swash zone.
基金sponsored by the Research Center of Ocean Environment and Technology under Grant No. D99-1500the Science Council under Grant No. NSC-99-2915-I-006-044
文摘A physical parameter, fib, which was used to meet the forcing of primary short waves to be off-resonant before wave breaking, has been considered as an applicable parameter in the infra-gravity wave generation. Since a series of modulating wave groups for different wave conditions are perfonned to proceed with the resonant mechanism of infra- gravity waves prior to wave breaking, the amplitude growth of incident bound long wave is assumed to be simply controlled by the normalized bed slope, fib. The results appear a large dependence of the growth rate, a, of incident bound long wave, separated by the three-array method, on the normalized bed slope, fib. High spatial resolution of wave records enables identification of the cross-correlation between squared short-wave envelopes and infra-gravity waves. The cross- shore structure of infra-gravity waves over beaches presents the mechanics of incident bound- and outgoing free long waves with the formation of free standing long waves in the nearshore region. The wave run-up and amplification of infra-gravity waves in the swash zone appear that the additional long waves generated by the breaking process would modify the cross-shore structure of free standing long waves. Finally, this paper would further discuss the contribution of long wave breaking and bottom friction to the energy dissipation of infra-gravity waves based on different slope conditions.
