Journal of Tropical Oceanography >
Numerical simulation of wave motion over large roughness reef surfaces based on XBeach-NH
Received date: 2024-11-20
Revised date: 2025-02-19
Online published: 2025-02-24
Supported by
National Key Research and Development Program of China(2021YFC3100500)
Changsha University of Science and Technology 2023 Graduate Student Innovation Project(CSLGCX23058)
The wave phase-resolving non-hydrostatic model (XBeach-NH) is enhanced by incorporating a drag term based on the Morison equation to numerically simulate and analyze wave motion characteristics and drag coefficients on large-roughness reef surfaces. Model validation is performed by comparing the time series of free surface elevations at various positions, as well as wave height distributions and mean water levels along the reef, for both smooth and rough reef surfaces. The validated numerical model is then employed to compare spatiotemporal distribution characteristics of free surface elevations near the reef edge and on the reef flat for both smooth and rough surface conditions. Furthermore, simulation results are used to determine optimal drag coefficient values for all experimental conditions involving rough reef surfaces. Results indicate that the XBeach-NH model effectively simulates wave propagation along reefs, and the Morison-based drag term reasonably captures the resistance characteristics of rough reef surfaces. The presence of roughness elements induces greater bottom frictional damping, resulting in significantly smaller wave height increases along rough reef surfaces compared to smooth ones. Higher harmonics and free waves emerge during wave propagation, with both smooth and rough reef surfaces exhibiting second or even higher-order harmonics. Notably, reef roughness substantially reduces second harmonic magnitudes. On rough surfaces, wave energy experiences significant dissipation due to roughness elements. Drag coefficients are larger under conditions of shallow water depth and small wave heights, attributable to increased flow resistance in shallow conditions. Longer wave periods (long waves) also yield large drag coefficients, while under large wave height conditions (strong nonlinearity), drag coefficient variations primarily depend on reef flat water depth. This study of wave motion characteristics under large coral reef surface roughness provides scientific insights for disaster prevention and mitigation along coral reef coasts during extreme wave events such as typhoons.
YAO Yu , LIU Xiaona , ZHOU Baobao , ZHOU Ting . Numerical simulation of wave motion over large roughness reef surfaces based on XBeach-NH[J]. Journal of Tropical Oceanography, 2025 , 44(5) : 31 -38 . DOI: 10.11978/2024211
图2 标准工况(H0=0.08m, T=1.5s, hr=0.10m)下3种网格尺寸(0.01m、0.02m和0.03m)的波高和平均水位的沿礁分布a, c: 光滑礁面; b, d: 粗糙礁面 Fig. 2 Along-reef distributions of wave height and mean water level for three grid sizes (0.01 m, 0.02 m and 0.03 m) under standard conditions (H0=0.08 m; T=1.5 s; hr=0.10 m). (a, c) smooth reef surface; (b, d) rough reef surface |
图3 标准工况(H0=0.08m, T=1.5s, hr=0.10m)下沿礁有代表性测量位置(G1、G3、G6、G9、G14和G18)自由液面的时间序列左列: 光滑礁面; 右列: 粗糙礁面 Fig. 3 Time series of free surface elevation at representative measurement positions (G1, G3, G6, G9, G14 and G18) along the reef under standard conditions (H0=0.08 m; T=1.5 s; hr=0.10 m). Left panels: smooth reef surface; right panels: rough reef surface |
图4 标准工况(H0=0.08m, T=1.5s, hr=0.10m)下波高(a、b)和平均水位(c、d)的沿礁分布a, c: 光滑礁面; b, d: 粗糙礁面 Fig. 4 Along-reef distributions of (a, b) wave height (H) and (c, d) mean water level (MWL) under standard conditions (H0=0.08 m; T=1.5 s; hr=0.10 m).(a, c) smooth reef surface; (b, d) rough reef surface |
图6 标准工况(H0=0.08m, T=1.5s, hr=0.10m)下礁缘附近波浪自由液面时空分布a. 光滑礁面; b. 粗糙礁面。黑色实线为主频波, 黑色虚线为二次谐波 Fig. 6 Spatiotemporal distributions of wave free surface near the reef edge under standard conditions (H0=0.08 m; T=1.5 s; hr=0.10 m). (a) smooth reef surface; (b) rough reef surface. Black solid lines represent primary frequency waves; black dashed lines indicate second harmonics |
| [1] |
贾美军, 姚宇, 何天城, 等, 2020. 大糙率礁面影响下珊瑚礁海岸附近规则波演化及爬高试验研究[J]. 海洋与湖沼, 51(6): 1344-1349.
|
| [2] |
姚宇, 2019. 珊瑚礁海岸水动力学问题研究综述[J]. 水科学进展, 30(1): 139-152.
|
| [3] |
姚宇, 蒋昌波, 2023. 珊瑚礁海岸水沙动力学[M]. 北京: 科学出版社.
|
| [4] |
姚宇, 周宝宝, 2024. 珊瑚礁冠层水动力学问题研究综述[J]. 海洋学报, 46(1): 1-11.
|
| [5] |
钟丹妮, 姚宇, 周婷, 2025. 孤立波作用下三维堡礁地形附近波浪传播变形及爬高研究[J]. 热带海洋学报, 44(2): 39-47.
|
| [6] |
|
| [7] |
|
| [8] |
|
| [9] |
|
| [10] |
|
| [11] |
|
| [12] |
|
| [13] |
|
| [14] |
|
| [15] |
|
| [16] |
|
| [17] |
|
| [18] |
|
| [19] |
|
| [20] |
|
| [21] |
|
| [22] |
|
| [23] |
|
/
| 〈 |
|
〉 |