臺灣國際科展

東方帆船推進原理探討

科展類別
臺灣國際科展
屆次
2003年
科別
工程學
學校名稱
臺北市立麗山高級中學
指導老師
吳明德
作者
賴威成
關鍵字
推進原理,機翼
備註
香港第卅六屆聯校科學展覽會

摘要或動機

本文研究風洞中之風帆在不同條件下,受風吹拂所產生之升力與阻力關係,並探討及成功 的以數學模型解釋其原因,此研究結果可應用於帆船帆面之設計。其主要探討之變因為以下 之五種: (一) 風速大小對帆船帆面之受力關係:當帆面與風向垂直時,在低風速時,實際測值較接近 風速的一次方的函數關係。高風速時,實際測值接近為風速的二次方的函數關係。 (二) 帆面積大小與受風推進力之關係:當帆面與風向垂直時,在風速固定風速下實驗,得到 面積與風對帆推力成正比。 (三) 順風航行時,帆面之攻角(θ)與受風推進力之關係:航行方向的力與sin 2θ 成正比關係。 (四) 側風航行時,帆面之攻角(θ)與受風推進力之關係:帆面在攻角大於 45°時,航行方向的力與sin θcosθ 有相當程度的吻合,而在攻角0°~45°之間則與飛機攻 角升力資料相接近。 (五) 初步探討雙桅帆與單桅帆面受風推進力之不同:發現其在側風時能有效的減少失速的現 象,在帆面高攻角時,能減少失速現象,依然可以持續穩定的航行,我們也可推想出飛機 的機翼前段的縫翼功能也是如此。 This article is derived from our research of relation between lifting power and its resistant power produced via wind-blow in a wind tunnel under different terms and condition, also to discuss and to explain their causes successfully via mathematics models, thus, the result of this study may be applied in designing of sail-surfaces of sails boats. Its major discussion can be included into the below 5 kinds: - Relation of (1) Relation of sizes of wind-speed against reacceptance of aerodynamic forces over sail-surface: When sail-surface and wind direction becomes horizontal, under low coin-speed, practical measured-value is rather close to wind-speed's linear function relation. When in nigh wind-speed, the practical measured-value is rather close to wind-speed's quadratic function relation. (2) Relation of size of sail-surface and pushing power of wind: When sail-surface and wind direction becomes horizontal, an experiment was made under fixed wind speed, the result obtained is sail-surface size and pushing wind power toward sail is in direct proportion. (3) When it is in “round-the-clock wise” navigation the angle of attack (θ) of sail-surface and the relation with wind's pushing power: Strength of navigation direction and sin2θconforming direct proportion. (4) When it is in side-wind navigation, the angle of attack (θ) and pushing power by wind relation; When the sail surface is in the angle of attack (θ) greater than 45o, the navigation direction power and sinθcosθhas certain extent of conformity, and between angle of attack e 0o-45o, happens to be very appropriate with aircraft's angle of attack and lifting power data. Fundamental discussion of Double Masts Sail boats and Single Mast Sail boats comparing differences of wind-aided pushing power: It was found that stall phenomena could be decreased effectively, when it is side-winded, especially, when the sail-surface is at high angle of attack, it could decrease Stall phenomena, and could maintain stable navigation. We can also assume that the front section of aircraft aide-wing’s function exactly the same.


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