Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, TN, USA.
Department of Mechanical Engineering, Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955, Kingdom of Saudi Arabia.
Commun Biol. 2024 Mar 1;7(1):248. doi: 10.1038/s42003-024-05913-3.
Winged, autorotating seeds from the genus Acer, have been the subject of study for botanists and aerodynamicists for decades. Despite this attention and the relative simplicity of these winged seeds, there are still considerable gaps in our understanding of how samara dynamics are informed by morphological features. Additionally, questions remain regarding the robustness of their dynamics to morphological alterations such as mass change by moisture or area change by damage. We here challenge the conventional approach of using wing-loading correlations and instead demonstrate the superiority of a classical aerodynamic model. Using allometry, we determine why some species deviate from interspecific aerodynamic behavior. We alter samara mass and wing area and measure corresponding changes to descent velocity, rotation rate, and coning angle, thereby demonstrating their remarkable ability to autorotate despite significant morphological alteration. Samaras endure mass changes greater than 100% while maintaining descent velocity changes of less than 15%, and are thus robust to changes in mass by moisture or damage. Additionally, samaras withstand up to a 40% reduction in wing area before losing their ability to autorotate, with the largest wings more robust to ablation. Thus, samaras are also robust to wing damage in their environment, a fact children joyfully exploit.
翅果，槭属植物的一种，具有翼的、能自转的种子，几十年来一直是植物学家和空气动力学家研究的对象。尽管人们对这些翅果给予了关注，而且这些翅果的形态相对简单，但我们对翼果动力是如何受到形态特征影响的理解仍然存在很大的差距。此外，关于它们的动力对水分引起的质量变化或损伤引起的面积变化等形态改变的稳健性，仍然存在一些问题。我们在这里挑战使用翼载荷相关性的传统方法，而是展示了经典空气动力学模型的优越性。通过比较不同物种之间的大小关系，我们确定了为什么有些物种会偏离种间空气动力学行为。我们改变了翅果的质量和翼面积，并测量了下降速度、旋转速度和锥形角的相应变化，从而展示了它们在经历显著形态改变的情况下仍能出色地自转的能力。尽管翅果的质量发生了超过 100%的变化，但下降速度的变化仍小于 15%，因此它们对水分或损伤引起的质量变化具有很强的稳健性。此外，翅果在失去自转能力之前，其翼面积可以减少 40%，而最大的翅膀对消融的抵抗力更强。因此，翅果对环境中的翼损伤也具有很强的稳健性，这一事实让孩子们非常高兴地加以利用。
