Many aquatic plants are flexible and bend in response to current. This reconfiguration can reduce the drag on the plant, both by reducing the frontal area and by creating a more streamlined shape. Previous studies have considered how the buoyancy and rigidity of a plant impact the drag reduction. This study additionally considered how reconfiguration impacts the sheltering between leaves on a plant and how this, in turn, impacts the drag on the plant. The posture and drag of single‐stemmed, leaved plants were studied through a combination of laboratory experiments and theoretical modeling using both plastic Rotala bonsai and live Bacopa caroliniana. The laboratory experiments measured drag and posture on individual plants over a range of channel velocity. The theoretical model calculated plant posture and drag based on a force balance that included buoyancy, the restoring force due to stem stiffness, and leaf drag modified to account for sheltering between leaves. Leaf sheltering was characterized by a sheltering coefficient, C_s, which is a function of the plant posture, leaf angle, leaf spacing, and leaf width. C_s decreased from 1 to a minimum value, C_s0, associated with a fully deflected, horizontal stem posture. Once validated, the model was used to explore a range of leaf configurations, following examples found in real plants. The modeling and experiments revealed conditions for which drag increased with reconfiguration, and also that the drag reached a finite, limiting value for horizontal stem posture. Neither trend has been described in previous reconfiguration models.

中文翻译：

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流动诱导的水生植物重构，包括叶片遮蔽的影响

许多水生植物具有柔韧性，并能响应水流而弯曲。这种重新配置可以通过减少正面面积和创建更流畅的形状来减少对植物的阻力。先前的研究已经考虑了植物的浮力和刚度如何影响减阻作用。这项研究还考虑了重新配置如何影响植物叶片之间的遮蔽，以及反过来又如何影响植物上的阻力。通过使用塑料Rotala盆景和活的Bacopa caroliniana的实验室实验和理论建模相结合的方法，对单茎有叶植物的姿势和阻力进行了研究。。实验室实验测量了通道速度范围内单个植物的阻力和姿势。该理论模型基于力平衡来计算植物姿态和阻力，该力平衡包括浮力，由于茎刚度而产生的恢复力以及为适应叶子之间的遮蔽而修改的叶子阻力。叶片遮蔽的特征在于遮蔽系数C _s，它是植物姿态，叶片角度，叶片间距和叶片宽度的函数。C _s从1降至最小值C _{s 0}，与完全偏转的水平杆姿势相关。验证后，将按照实际植物中发现的示例，使用该模型探索一系列叶片配置。建模和实验揭示了阻力随重新配置而增加的条件，并且阻力达到了水平杆姿势的有限极限值。先前的重新配置模型都未描述这两种趋势。