【摘要】：在現(xiàn)代足球154年的歷史歲月中,誕生了無數(shù)令人印象深刻的進(jìn)球,而其中有一類,因其自身的特殊性質(zhì),媒體和大眾輿論常常使用這樣一個名稱來形容它的詭異——Violate the laws of Physics Goal (違反物理學(xué)規(guī)律的進(jìn)球),這便是S型任意球。本文收集與整理大量S型任意球影像與訪談材料,探索關(guān)于足球運(yùn)動中S型任意球的界定、原理和發(fā)生機(jī)制,進(jìn)而提出訓(xùn)練建議,為S型任意球的相關(guān)研究提供參考。本文以流體力學(xué)中 Bernoulli's principle、Magnus Effect、Karman Vortex Street等相關(guān)理論為基礎(chǔ),以數(shù)學(xué)方法為手段界定S型任意球,推導(dǎo)和計算S型任意球的形成機(jī)理和發(fā)生機(jī)制;通過大量相關(guān)影像資料,歸納分析S型任意球的特征;使用定量分析法,通過對S型任意球相關(guān)影響因子的準(zhǔn)確賦值,使對S型任意球軌跡與形成的探索進(jìn)一步細(xì)化,更加科學(xué)的、客觀的揭示S型任意球的形成與運(yùn)動規(guī)律,把握本質(zhì),理清關(guān)系,并繪圖預(yù)測趨勢和走向;同時查閱文獻(xiàn)資料,總結(jié)當(dāng)下國內(nèi)外前沿的下肢快速力量訓(xùn)練理論以及優(yōu)秀運(yùn)動員的成功經(jīng)驗,為S型任意球的訓(xùn)練提供可行建議。通過研究得到:(1) S型任意球形成的基本原理為Karman Vortex Street,足球飛行過程中雷諾數(shù)介于3×105與3×106之間時,在足球后方形成的非線性渦街是S型軌跡產(chǎn)生的本質(zhì)。(2) S型任意球的形成需要兩個必要條件,第一是不旋轉(zhuǎn)條件,擊球時需控制足球在飛行過程中幾乎不帶有產(chǎn)生橫截面上的角速度;第二是高速條件,必須讓足球在飛行過程中存在一個時間片段,該時間片段內(nèi),足球的速度標(biāo)量始終不低于“逃逸速度Vmin”,而該時間片段的長度,決定S型軌跡顯著程度。(3)以標(biāo)準(zhǔn)大氣壓和20℃為通常狀況,通過計算,足球逃逸速度Vmin=21.0m/s。(4)逃逸速度Vmin的主要影響因子為空氣密度ρ、空氣黏性系數(shù)μ;不同氣溫下空氣密度ρ、空氣黏性系數(shù)μ也隨著變化,通過計算與繪圖,發(fā)現(xiàn)溫度較低時,產(chǎn)生S型軌跡需要的逃逸速度Vmin也越小。(5) S型任意球訓(xùn)練以發(fā)展下肢快速力量和針對性技巧為主,進(jìn)行向心結(jié)合不同速度離心訓(xùn)練和技巧性訓(xùn)練。
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圖片說明：圖１交點定義法示意圖逡逑
[Abstract]:In the 154th history of modern football, countless impressive goals have been born, and one of them, because of its own special nature, the media and public opinion often use such a name to describe its weirdness-Violate the laws of Physics Goal (goals against the laws of physics), this is the S-shaped free-kick. In this paper, a large number of S-type free-kick images and interview materials are collected and sorted out, the definition, principle and occurrence mechanism of S-type free-kick in football are explored, and then the training suggestions are put forward, which provides a reference for the related research of S-type free-kick. Based on Bernoulli's principle,Magnus Effect,Karman Vortex Street and other related theories in fluid mechanics, this paper defines S-type free-kick by means of mathematical method, deduces and calculates the formation mechanism and occurrence mechanism of S-type free-kick, sums up and analyzes the characteristics of S-type free-kick through a large number of related image data. By using quantitative analysis method, through the accurate assignment of the influencing factors of S-type free-kick, the exploration of the trajectory and formation of S-type free-kick is further refined, and the formation and movement law of S-type free-kick are revealed more scientifically and objectively, the essence is grasped, the relationship is clarified, and the trend and trend are predicted by drawing. At the same time, the literature is consulted to summarize the theory of rapid strength training of lower extremity at home and abroad and the successful experience of excellent athletes, so as to provide feasible suggestions for the training of S-type free kick. The results show that: (1) the basic principle of the formation of S-type free-kick is that when the Reynolds number is between 3 脳 10 ~ 5 and 3 脳 10 ~ 6 in the flight process of Karman Vortex Street, football, the nonlinear vortex street formed in the rear of football is the essence of S-shaped trajectory. (2) the formation of S-type free-kick requires two necessary conditions, the first is the condition of non-rotation, and the angular velocity of football is almost without cross section in the course of hitting the ball; The second is the high speed condition, in which the velocity scalar of the football is not lower than the "escape velocity Vmin", and the length of the time segment determines the remarkable degree of the S-shaped trajectory. (3) taking the standard atmospheric pressure and 20 鈩，

本文編號：2512258