Interaction of waves and currents with kelp forests (Macrocystis pyrifera): Insights from a dynamically scaled laboratory model
Interaction of waves and currents with kelp forests (Macrocystis pyrifera): Insights from a dynamically scaled laboratory model
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波浪和海流与海带森林（Macrocystis Pyrifera）的相互作用：来自动态缩放实验室模型的见解
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发表时间：
2013
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影响因子：
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通讯作者：
J. Koseff
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作者：
Johanna H. Rosman;Mark W. Denny;R. B. Zeller;S. Monismith;J. Koseff
在实验室水槽中，使用动态匹配的1/25比例物理模型，在受控条件下研究了表面波和海流与海带森林的相互作用。在海带模拟实验中，波浪将时间平均阻力增加了2倍，并改变了水流剖面的形状。模型海带和波浪下的水之间的相对运动增加了湍流的产生，导致湍流动能比无波浪的实验大2-5倍，涡流粘度大20-50%。由于混合长度在模型海带森林中减少到尾流尺度，因此涡动粘度比没有海带时小25-50%。在固体障碍物间隔最密集的海带森林表面冠层模型中，波轨道速度从线性波理论预测中降低了10%。这种波轨道速度的降低被认为主要是由于模型海带对水施加的惯性力。由于波轨道速度的变化，斯托克斯漂移减少了20%。虽然海带森林内的流体动力学比实验室实验更复杂，并且可能发生各种各样的流动条件，但实验室结果表明：（1）海带森林阻力因波浪而增加;（2）波浪特性可因阻力和惯性力而改变;（3）波浪引起的湍流尾流可能是密集海带林中湍流的主要来源。因此，在开发这些系统中的阻力和混合模型时，必须考虑到海带和波浪之间的相互作用。
The interaction of surface waves and currents with kelp forests was examined under controlled conditions using a dynamically matched 1/25‐scale physical model in a laboratory flume. In experiments with kelp mimics, waves increased the time‐averaged drag by a factor of 2 and altered the shape of current profiles. Relative motion between model kelp and water under waves increased wake generation of turbulence, resulting in turbulent kinetic energies 2–5 times larger, and eddy viscosities 20–50% larger, than for experiments without waves. Because mixing lengths were reduced to wake‐scales in the model kelp forest, eddy viscosities were 25–50% smaller than when kelp was absent. In the model kelp‐forest surface canopy where solid obstacles were most densely spaced, wave orbital velocities were reduced by ∼ 10% from linear wave theory predictions. This decrease in wave orbital velocities is thought to result primarily from inertial forces exerted on water by model kelp. Stokes drift was reduced by ∼ 20% as a result of the change in wave orbital velocities. Although hydrodynamics within kelp forests are more complex than in the laboratory experiments and a wide range of flow conditions can occur, laboratory results suggest that (1) kelp forest drag is increased by waves; (2) wave properties can be altered by drag and inertial forces; and (3) wake production of turbulence caused by waves may be the main source of turbulence in dense kelp stands. Interactions between kelp and waves must therefore be taken into account when developing models for drag and mixing in these systems.