A platform for research: civil engineering, architecture and urbanism
Frictional swash hydrodynamics under the improved seaward boundary condition
Abstract Effects of the improved seaward boundary condition on the swash zone hydrodynamics with bottom resistance are investigated using the method of characteristics. The characteristic equations including the Chezy-type resistance term are solved numerically by using the specified time interval scheme. Following Guard and Baldock (2007), the improved seaward boundary condition is introduced after incorporating a parameter k. Spatiotemporal distribution of the forward and backward characteristic lines under different bottom frictions and k parameters are specified. Large k parameter postpones the swash flow reversal time and extends the entire swash duration, which enhances/reduces the function of pressure force/bottom friction in swash hydrodynamics. During the late backwash stage, the bottom resistance effect becomes less influential with the increase of parameter k. Shoreline movement is mainly controlled by the bottom friction initially, then by gravity around the swash flow reversal, and by the joint actions of bottom friction and gravity (or hydrostatic pressure and gravity) in the case of k = 0 (or k = 1) near the late backwash stage. With respect to the entire swash duration, the flow reversal time at the shoreline, the maximum run-up height and the maximum backwash velocity, it is confirmed that the effects of the boundary condition parameter k on the swash hydrodynamics become more significant under the large bottom resistance. The present study extends Deng et al. (2016)'s work with the improved seaward boundary conditions and makes it more applicable to the actual swash process. Findings from the present study could further improve our understandings of the frictional swash hydrodynamics.
Highlights A numerical solution of frictional swash hydrodynamics was deduced with an improved seaward boundary condition (ISBC). ISBC with a large parameter enhances/reduces the effect of pressure force/bottom friction on the swash flow acceleration. Influence of each force component on the shoreline movement is clarified under different ISBCs. ISBC increases the entire swash duration, extends the maximum run-up height, but reduces the maximum backwash velocity. Effects of ISBC on the swash hydrodynamics are confirmed to be more significant under the large bottom friction.
Frictional swash hydrodynamics under the improved seaward boundary condition
Abstract Effects of the improved seaward boundary condition on the swash zone hydrodynamics with bottom resistance are investigated using the method of characteristics. The characteristic equations including the Chezy-type resistance term are solved numerically by using the specified time interval scheme. Following Guard and Baldock (2007), the improved seaward boundary condition is introduced after incorporating a parameter k. Spatiotemporal distribution of the forward and backward characteristic lines under different bottom frictions and k parameters are specified. Large k parameter postpones the swash flow reversal time and extends the entire swash duration, which enhances/reduces the function of pressure force/bottom friction in swash hydrodynamics. During the late backwash stage, the bottom resistance effect becomes less influential with the increase of parameter k. Shoreline movement is mainly controlled by the bottom friction initially, then by gravity around the swash flow reversal, and by the joint actions of bottom friction and gravity (or hydrostatic pressure and gravity) in the case of k = 0 (or k = 1) near the late backwash stage. With respect to the entire swash duration, the flow reversal time at the shoreline, the maximum run-up height and the maximum backwash velocity, it is confirmed that the effects of the boundary condition parameter k on the swash hydrodynamics become more significant under the large bottom resistance. The present study extends Deng et al. (2016)'s work with the improved seaward boundary conditions and makes it more applicable to the actual swash process. Findings from the present study could further improve our understandings of the frictional swash hydrodynamics.
Highlights A numerical solution of frictional swash hydrodynamics was deduced with an improved seaward boundary condition (ISBC). ISBC with a large parameter enhances/reduces the effect of pressure force/bottom friction on the swash flow acceleration. Influence of each force component on the shoreline movement is clarified under different ISBCs. ISBC increases the entire swash duration, extends the maximum run-up height, but reduces the maximum backwash velocity. Effects of ISBC on the swash hydrodynamics are confirmed to be more significant under the large bottom friction.
Frictional swash hydrodynamics under the improved seaward boundary condition
Zeng, Jun (author) / Liu, Haijiang (author)
Coastal Engineering ; 169
2021-07-17
Article (Journal)
Electronic Resource
English
The influence of seaward boundary conditions on swash zone hydrodynamics
Online Contents | 2007
|The influence of seaward boundary conditions on swash zone hydrodynamics
British Library Online Contents | 2007
|The influence of seaward boundary conditions on swash zone hydrodynamics
Elsevier | 2006
|