A volume penalization immersed boundary method for flow interactions with aquatic vegetation
A volume penalization immersed boundary method for flow interactions with aquatic vegetation
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水流与水生植被相互作用的体积惩罚浸入边界法
DOI：
10.1016/j.advwatres.2021.104120
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发表时间：
2022
影响因子：
4.7
通讯作者：
Yu, M.-L.
中科院分区：
文献类型：
--
作者：
Yu, X.;Yu, M.-L.
发展了一种研究水流与水生植被相互作用的体积惩罚浸没边界（VPIB）方法。该模型已与实验室的实验数据和以前的高保真模型进行了验证，结果令人满意。对罚函数参数和厚度参数进行了灵敏度分析，并给出了这些参数的最佳取值。应用该模型研究了植被茎杆摆动对植被-茎杆尺度和斑块尺度水流动力学的影响。植物茎的摇摆运动遵循三次定律，在顶部达到峰值，在底部减小到零。在树干尺度上，水动力学取决于KeuleganCarpenter数（KC），KC被定义为植被树干相对于树干直径的最大偏移。进行了三个KC值的模拟。当KC ≥ 1时，尾柱的摇摆运动显著增强了尾流的湍流度，尾流湍流度变得更加各向同性。植物茎的摇摆运动引起茎肩处的底部剪应力增加5%，而在尾流中这种影响可以忽略不计。在斑块尺度上，水动力取决于基于植被斑块大小的有效Keulegan Carpenter数，以及密集植被冠层的固体体积分数。固体体积分数是不同的，同时保持相同的有效Keulegan木匠在模拟。当有效Keulgen-Carpenter数较小时（KC < 1），植被树干的摇摆运动对大斑块尺度动力学的影响不显著，包括湍流统计和底应力。
A volume-penalization immersed boundary (VPIB) method was developed to study flow interactions with aquatic vegetation. The model has been validated with data from laboratory experiments and previous high-fidelity models with satisfactory results. Sensitivity analyzes on both penalty parameter and thickness parameter were conducted, and optimal values for these parameters are recommended. The validated model has been applied to study the effects of swaying motion of vegetation stems on the flow dynamics at both vegetate-stem scale and patch scale. The swaying motion of the vegetation stem is prescribed following a cubic law that peaks at the top and decreases to zero at the bottom. At stem-scale, the hydrodynamics depend on the Keulegan Carpenter number (K C), which is defined as the maximum excursion of the vegetation stem to the diameter of the stem. Simulations with three K C values were carried out. For K C≥ 1, the flow turbulence is significantly enhanced by the swaying motion of the stem, and turbulence becomes more isotropic in the wake. The swaying motion of vegetation stems caused a 5% increase of the bottom shear stress at the shoulders of the stem, and the effect is negligible in the wake. At patch-scale, the hydrodynamics depend on the effective Keulegan Carpenter number based on the patch size of the vegetation patch, and the solid volume fraction for dense vegetation canopy. Solid volume fraction was varied while maintaining the same effective Keulegan Carpenter in the simulations. When the effective Keulgen Carpenter number is small (K C< 1), effects of the swaying motion of vegetation stems on the large patch-scale dynamics are not significant, including both the turbulence statistics and the bottom stress.