以近海风电伞式吸力锚基础为研究对象,进行室内水槽试验和数值模拟,研究波浪作用下伞式吸力锚基础周围冲刷演变机制,分别基于Raaijmakers和Myrhaug模型,提出随机波浪小Keulegan-Carpenter数（KC）情况下伞式吸力锚基础周围平衡冲刷深度预测模型。结果表明：随机波浪下,波峰时形成的旋涡体系主导冲刷过程,此时基础上游逆压梯度最大,这有利于波浪边界层充分分离,形成马蹄形旋涡,马蹄形旋涡和桩侧流线压缩导致筒裙上游两侧约45°圆心角位置剪切流速最大,筒裙和锚枝的设置保护了该位置床面土体,使得最大冲刷深度位置位于锚枝之间。当KC采用KCs,p,且KCs,p<8时,修正Raaijmakers模型预测的平衡冲刷深度Seq'与计算值具有较好的一致性,当KCs,p>8时,预测值与试验值之间的误差变大,修正Raaijmakers模型过分估计了平衡冲刷深度。当KCrms,a<4,n=10时,修正Myrhaug平衡冲刷深度预测模型预测效果最好。
Abstract
A series of wave flume experiments and numerical simulation were conducted under waves, so as to investigate the scour mechanism around umbrella suction anchor foundation （USAF） of offshore wind turbines. Then, two revised models were proposed according to the model of Raaijmakers and Myrhaug model respectively to predict the equilibrium scour depth around USAF for low Keulegan-Carpenter number （KC） under waves. The results indicated that the vortex system at wave crest phase is mainly responsible for the scour process under waves. What's more, due to the combination of the horseshoe vortex and streamline compression, the maximum scour depth occurred at the upside of the USAF with an angle of about 45° corresponding to the wave propagating direction. The tube skirt and anchor branches play a role in protecting the scour around USAF to some extent. The revision model based on Raaijmakers's model shows good agreement with the simulating results of the present study for KCs,p<8. However, the gap between the predicting results and experimental data becomes large and the Eq.（25） overestimates the equilibrium scour depth to some extent for KCs,p>8. The predicting results of another revision model based on the stochastic model are the most favorable for n=10 when KCrms,a<4.
关键词
冲刷 /
平衡冲刷深度 /
KC数 /
海上风电基础
Key words
scour /
equilibrium scour depth /
KC number /
offshore wind turbine foundation
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参考文献
[1] 梁发云, 王琛, 黄茂松, 等. 沉井基础局部冲刷形态的体型影响效应与动态演化[J]. 中国公路学报, 2016, 29(9): 59-67.
LIANG F Y, WANG C, HUANG M S, et al.Scale effects on local scour configurations around caisson foundation and dynamic evolution[J]. China journal of highway and transport, 2016, 29(9): 59-67.
[2] 袁春光, 王义刚, 张义丰, 等. 潮流条件下的桩基冲刷深度研究[J]. 水道港口, 2019, 40(3): 273-278.
YUAN C G, WANG Y G, ZHANG Y F, et al.Study of pier scour under a tidal current[J]. Journal of waterway and harbor, 2019, 40(3): 273-278.
[3] 刘红军, 李洪江. 黄河三角洲海上风机新型吸力锚基础型式分析[J]. 中国海洋大学学报, 2014, 44(7): 71-76.
LIU H J, LI H J.A new suction anchor foundation of the Yellow River Delta offshore wind power[J]. Journal of Ocean University of China, 2014, 44(7): 71-76.
[4] 刘红军, 王奎迪, 唐慧玲. 海上风机伞式吸力锚基础结构优化设计及承载优势分析[J]. 中国海洋大学学报, 2016, 46(9): 96-101.
LIU H J, WANG Q D, TANG H L.Optimum structural design and loading advantages analysis of umbrella suction anchor foundation for offshore wind turbine[J]. Journal of Ocean University of China, 2016, 46(9): 96-101.
[5] 王伟, 杨敏. 海上风电机组地基基础设计理论与工程应用[M]. 北京: 中国建筑工业出版社, 2014.
WANG W, YANG M.Design theory and applications of offshore wind turbine foundation[M]. Beijing: China Architecture & Building Press, 2014.
[6] UMEDA S.Scour regime and scour depth around a pile in waves[J]. Journal of coastal research, 2011, S64: 845-849.
[7] SUMER B M, CHRISTIANSEN N, FREDSØE J. The horseshoe vortex and vortex shedding around a vertical wall-mounted cylinder exposed to waves[J]. Journal of fluid mechanics, 1997, 332: 41-70.
[8] ROULUND A, MUTLU SUMER B, FREDSØE J, et al. Numerical and experimental investigation of flow and scour around a circular pile[J]. Journal of fluid mechanics, 2005, 534: 351-401.
[9] SUMER B M, FREDSØE J, CHRISTIANSEN N. Scour around vertical pile in waves[J]. Journal of waterway, port, coastal, and ocean engineering, 1992, 118(1): 15-31.
[10] CORVARO S, MARINI F, MANCINELLI A, et al.Hydro-and morpho-dynamics induced by a vertical slender pile under regular and random waves[J]. Journal of waterway, port, coastal, and ocean engineering, 2018, 144(6): 04018018.
[11] RUDOLPH D, BOS K.Scour around a monopile under combined wave-current conditions and low KC-numbers[C]//Proceedings of the 6th International Conference on Scour and Erosion, Amsterdam, Netherlands, 2006: 582-588.
[12] RAAIJMAKERS T, RUDOLPH D.Time-dependent scour development under combined current and waves conditions - Laboratory experiments with online monitoring technique[C]//Proceedings of the 4th International Conference on Scour and Erosion, Tokyo, Japan, 2008:152-161.
[13] ZANKE U C E, HSU T W, ROLAND A, et al. Equilibrium scour depths around piles in noncohesive sediments under currents and waves[J]. Coastal engineering, 2011, 58(10): 986-991.
[14] KHALFIN I S.Modeling and calculation of bed score around large-diameter vertical cylinder under wave action[J]. Water resources, 2007, 34(3): 357-357.
[15] SUMER B M, FREDSØE J. Scour around pile in combined waves and current[J]. Journal of hydraulic engineering, 2001, 127(5): 403-411.
[16] MYRHAUG D, RUE H, Scour below pipelines and around vertical piles in random waves[J]. Coastal engineering, 2003,48(4): 227-242.
[17] MYRHAUG D, ONG M C.Random wave-induced onshore scour characteristics around submerged breakwaters using a stochastic method[J]. Ocean engineering, 2010, 37(13): 1233-1238.
[18] WHITEHOUSE R.Scour at marine structures: a manual for practical applications[M]. London: Thomas Telford Ltd., 1998.
[19] LANÇA R, FAEL C, MAIA R, et al. Clear-water scour at pile groups[J]. Journal of hydraulic engineering, 2013, 139: 1089-1098.
[20] RIJN V, LEO C.Sediment transport, part I: bed load transport[J]. Journal of hydraulic engineering, 1985, 110(10): 1431-1456.
[21] SOULSBY R.Dynamics of marine sand[M]. London: Thomas Telford Publications, 1997.
[22] MASTBERGEN D R, BERG J H V D. Breaching in fine sands and the generation of sustained turbidity currents in submarine canyons[J]. Sedimentology, 2010, 50(4): 625-637.
[23] 俞聿修, 柳淑学. 随机波浪及其工程应用[M]. 大连: 大连理工大学出版社, 2011.
YU Y X, LIU S X.Random wave and its engineering application[M]. Dalian: Dalian University of Technology Press, 2011.
[24] 于通顺, 齐越, 奚泉. 考虑波浪作用相位关系的复合筒型基础地基液化研究[J]. 太阳能学报, 2017, 38(4): 1150-1156.
YU T S, QI Y, XI Q.Liquefaction analysis of seabed around composite bucket foundation considering phase relation between wave force andwave pressure on seabed[J]. Acta energiae solaris sinica, 2017, 38(4): 1150-1156.
[25] 程永舟, 姜松, 龚维亮, 等. 孤立波作用下淹没垂直桩柱局部冲刷试验研究[J]. 水科学进展, 2019, 30(2): 255-263.
CHENG Y Z, JIANG S, GONG W L, et al.Experimental study on local scour around the submerged vertical circular cylinder under solitary wave action[J]. Advances in water science, 2019, 30(2): 255-263.
[26] 程永舟, 唐雯, 李典麒, 等. 波浪作用下斜坡沙质海床上桩柱周围局部冲刷试验研究[J]. 水科学进展, 2018, 29(2): 260-268.
CHENG Y Z, TANG W, LI D Q, et al.Experimental study on local scour around the pile on the sandy seabed under wave action[J]. Advances in water science, 2018, 29(2): 260-268.
[27] 马丽丽, 国振, 王立忠, 等. 单向流条件下单桩桩周冲刷过程特征试验研究[J]. 海洋工程, 2017, 35(1): 136-146, 156.
MA L L, GUO Z, WANG L Z, et al.Scour characteristics at the periphery of a vertical pile under steady flow[J]. Ocean engineering, 2017, 35(1): 136-146, 156.
基金
中央高校基本科研业务费专项（202061027）; 国家自然科学基金（41572247）
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