請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92463
標題: | 以仿生翅果分析形態差異對擴散潛力的影響 ──以龍腦香科植物為例 Analyzing the Effect of Morphology in Biomimetic Winged Fruit on Dispersal Potential: A Case Study of Dipterocarp Trees |
作者: | 許雅淳 Ya-Chun Hsu |
指導教授: | 于宏燦 Hon-Tsen Yu |
關鍵字: | 種子傳播,仿生翅果,異速縮放法則,擴散潛力,前緣渦漩,翼荷比, seed dispersal,biomimetic winged fruit,allometric scaling law,dispersal potential,leading-edge vortex,wing-loading, |
出版年 : | 2024 |
學位: | 碩士 |
摘要: | 種子傳播對種子植物的基因擴散扮演重要角色,而不同於動物的靈活性,植物需要依靠樹木與果實等形態的變化與適應來達成不同的傳播形式。而現今氣候變遷與溫室效應加劇的情況下,了解森林地區的植物傳播機制,不僅有利於生態的維護與繁衍,亦可將其應用於仿生工程上。
前人研究主要以幾何單純的單翅果或雙翅果作為研究對象,並聚焦於錐角、曲率與摺角變化與翼荷比對擴散潛力的影響,幾何更為複雜的三翅果則鮮少有人研究。至今,多翅果的俯仰角對於擴散潛力之影響尚無人探討,並且二、三翅果的終端速度受翼荷比所影響的程度差異亦尚無人分析。因此,本研究以熱帶低地雨林地區的代表物種龍腦香科植物作為探討對象,蒐集了23種天然翅果的幾何參數,比較二、三翅果的異速縮放法則。並透過高速攝影機拍攝翅果落下過程,以自由落下實驗觀察了3個物種的擴散潛力,以及二翅果的失水現象與有無俯仰角對擴散潛力的改變。並且,透過摺紙與PET材料打造仿生翅果,以自由落下實驗分析仿生翅果在0°與20°俯仰角下的落下速度、旋轉頻率與飛行軌跡的差異,再以有限元素模擬分析兩俯仰角之紙摺翅果的周圍流場結構。最後,透過垂直風洞裝置分析PET二、三翅果隨著翼荷比的提升下,其終端速度與旋轉頻率的變化,以探討不同翅數的翼荷比對擴散潛力的影響。 在異速縮放法則中,龍腦香科二、三翅果在種間之種子的生長速率大於翅膀生長速率,但此異速縮放在二、三翅果中無顯著差異;而在三翅果Shorea roxburghii的種內觀察中,發現在尺寸變化上,不論種子還是翅膀皆以「長度」為主要縮放依據,並且尺寸變大的過程中,種子的生長速率大於翅膀。透過自由落下實驗,觀察到二翅果Dipterocarpus zeylanicus乾燥後的擴散潛力表現得不如新鮮翅果,儘管樣本數量有限,但此結果仍可作為翅果柔性探討的參考價值。此外,本研究觀察到有無俯仰角的二翅果Hopea odorata之擴散潛力存在差異,並且藉由仿生翅果發現在與0°俯仰角翅果具有相同翼荷比的情況下,具有20°俯仰角的仿生翅果之終端速度與0°俯仰角的幾乎相同,但旋轉頻率則為0°俯仰角的0.67倍,並且相對於採螺旋運動的0°俯仰角之仿生翅果,而20°俯仰角翅果的飛行軌跡更為筆直,上述差異可能與翅果翅膀表面的渦漩集中位置不同所致。最後,本研究發現PET二、三翅果的旋轉頻率與翼荷比無顯著關係,可能是受翅果形態所決定;而兩者的終端速度與翼荷比平方根的關係則為線性關係,其中,三翅果的終端速度隨翼荷比平方根變大而提升的數值更多,表示三翅果的終端速度更易受翼荷比的影響,而此現象似乎與天然三翅果的翼荷比範圍相對二翅果受限有關。 Seed dispersal is essential for the genetic spread of seed plants. Unlike the agility of animals, plants rely on various morphological changes such as trees and fruits to achieve dispersal. Given the current scenario of climate change and greenhouse effects, it is crucial to understand the mechanisms of seed dispersal in forest areas. This understanding is beneficial not only for ecological maintenance and reproduction but can also be applied to biomimetic engineering. Previous research studies have primarily focused on simple geometrically shaped single-winged or two-winged fruits. These studies have examined the effects of variations in cone angles, curvature, and folding angles on the dispersal potential of the winged fruits. However, there has been limited research on more complexly shaped fruits, such as three-winged fruits. To date, the impact of pitch angles on the dispersal potential of multi-winged fruits has not been explored. Also, the extent to which the terminal velocity of two- and three-winged fruits is influenced by wing-loading remains unanalyzed. Therefore, this study examines the process of seed dispersal in representative species of the tropical lowland rainforest, specifically the Dipterocarpaceae family. To accomplish this, the study collected geometric parameters of 23 natural winged fruits and compared the allometric scaling rules of two- and three-winged fruits. High-speed cameras were used to capture the falling process of winged fruits while conducting free fall experiments to observe the dispersal potential of three species. The study also looked at the effects of wing dehydration and pitch angle on the dispersal potential of two-winged fruits. To analyze the differences in falling velocity, rotational frequency, and flight trajectory of biomimetic winged fruits at 0° and 20° pitch angles, the study designed biomimetic winged fruits using origami paper and PET material. Also, finite element simulation was employed to analyze the surrounding flow field structure of origami winged fruits at both pitch angles. Finally, a vertical wind tunnel was used to analyze the variation in terminal velocity and rotational frequency of PET two- and three-winged fruits with increasing wing-loading, to investigate the effect of wing number differences on dispersal potential. The study examined the growth rate of seeds and wings in Dipterocarp fruits with two- and three-winged fruits. The seed growth rate was found to exceed the wing growth rate in both types of fruits. However, there was no significant difference in allometric scaling between two- and three-winged fruits. In the case of Shorea roxburghii (three-winged fruits), both seeds and wings primarily increased in "length" during size changes, with the seed growth rate surpassing that of the wings. The study also observed that the dispersal potential of dried two-winged fruits (Dipterocarpus zeylanicus) was lower than that of green-winged fruits. Although the sample size was limited, this result still holds value as a reference for the flexibility of winged fruits. Additionally, this study found differences in the dispersal potential of two-winged fruits (Hopea odorata) with and without pitch angles. Biomimetic winged fruits showed that under the same wing-loading, winged fruits with a 20° pitch angle had nearly the same terminal velocities as winged fruits with a 0° pitch angle, but had a 0.67-fold rotational frequency. The study also found that PET two- and three-winged fruits did not have a significant relationship between the rotational frequency and wing-loading, possibly due to the morphology of the winged fruits. The terminal velocity of PET two- and three-winged fruits increased linearly with the square root of the wing-loading. The terminal velocity of three-winged fruits increases more significantly with the square root of the wing-loading, suggesting that the terminal velocity of three-winged fruits is more influenced by the wing-loading, which may be related to the relatively restricted wing-loading range of natural three-winged fruits compared to two-winged fruits. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92463 |
DOI: | 10.6342/NTU202400022 |
全文授權: | 同意授權(限校園內公開) |
顯示於系所單位: | 生命科學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-112-1.pdf 目前未授權公開取用 | 9.12 MB | Adobe PDF | 檢視/開啟 |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。