Intra-wave-phase cross-shore profile modelling by using boundary-fitted slowly moving grid OTHER

Title
Intra-wave-phase cross-shore profile modelling by using boundary-fitted slowly moving grid
Alternative Title
Intra-wave-phase cross-shore profile modelling by using boundary-fitted slowly moving grid
Author(s)
Hyoseob Kim; Seung-Won Baek; Dae-hee Hwang; Kyoung-Pil Lee; 진재율; Chang-Hwan Jang
KIOST Author(s)
Jin, Jae Youll(진재율)
Publication Year
2016
Abstract
Coastal bed profile change is described by bed load, pick-up, and settling on a boundary-fitted moving grid. Existing bed load formula is modified by changing threshold bed shear stress to reflect local bed slope. A numerical model system adopting the above function is developed to simulate cross-shore sediment transport around swash zone with steep bed slope as well as surf zone. The model system adopts a moving boundary grid which fits bed boundary slope, and other horizontal grid lines are parallel to the bed grid line. The model system is composed of flow module and sediment transport module. The flow module solves continuity equation and Reynolds-average Navier-Stokes momentum equations in intra-wave-phase manner. The flow module provides detailed flow information including near-bed fluid velocity which varies asymmetrically within a regular wave period near sea-bed and wave-phase average undertow profile of main fluid body including wave boundary layer. The sediment transport module solves sediment mass conservation equation. Exchange of sediment mass between bed itself and fluid column containing suspended sediment happens through pick-up and deposition. Wild bed level undulation is controlled by using a smoothing method. Model system is applied to two extreme cases of sand experiments by Kajima et al., and reasonable agreements between measurements and computations are obtained for both onshore-dominant and odopting the above function is developed to simulate cross-shore sediment transport around swash zone with steep bed slope as well as surf zone. The model system adopts a moving boundary grid which fits bed boundary slope, and other horizontal grid lines are parallel to the bed grid line. The model system is composed of flow module and sediment transport module. The flow module solves continuity equation and Reynolds-average Navier-Stokes momentum equations in intra-wave-phase manner. The flow module provides detailed flow information including near-bed fluid velocity which varies asymmetrically within a regular wave period near sea-bed and wave-phase average undertow profile of main fluid body including wave boundary layer. The sediment transport module solves sediment mass conservation equation. Exchange of sediment mass between bed itself and fluid column containing suspended sediment happens through pick-up and deposition. Wild bed level undulation is controlled by using a smoothing method. Model system is applied to two extreme cases of sand experiments by Kajima et al., and reasonable agreements between measurements and computations are obtained for both onshore-dominant and o
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/2331
Bibliographic Citation
Journal of Mathematical Models in Engineering, v.2, no.2, pp.78 - 93, 2016
Type
Article
Language
English
Related Researcher
Research Interests

Sediment transport,Coastal erosion,Numerical modeling,퇴적물이동,연안침식,수치모델

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