基于数值模拟的帆船起航阶段调帆策略研究

帆船比赛中,起航阶段成功与否是比赛胜负关键之一。通过数值模拟方法得到了不同桅杆形状、不同扣角和倾角以及帆翼外形时帆翼空气动力系数随攻角变化关系。在帆翼空气动力性能数值模拟的基础上,分析发现,帆船起航阶段战术是保证帆船冲击力的关键,如果帆船运动员身体素质较佳,那么在确保帆船平衡的前提下,要调整帆船攻角、桅杆迎风位置、扣角和倾角以及帆船帆翼拱度大小,使得帆船帆翼整体推力性能达到相对较大。如果帆船起航时候占据有利的位置,就要在接下来的迎风航段不断牵制住其他帆船。该文通过探讨帆船起航阶段的调帆基本原则,为帆船运动员在起航阶段调帆争夺到有利位置提供科学指导。     

470级帆船在迎风行驶中器材的作用与调整

一、桅杆撑臂的调整 航程中发挥最佳迎风速度的前提,首先要保持船倾角的稳定。在能力足以控制船倾角稳定的风力条件下且水面较平,撑臂的角度较大单臂可拉长至490mm,促使桅杆的侧向弹性最小,纵向的弹性最大,有利于前主帆重叠喷口的气流释放,主帆后缘坚挺,保持最佳迎风速度的发挥。     

基于虚拟样机技术的风洞迎角机构设计及分析

迎角机构是风洞的关键部件之一,是试验模型的支撑,其运动精度和动态特性直接影响风洞试验精度。运用虚拟样机技术建立风洞迎角机构数字样机模型,并对迎角机构进行有限元、运动学及动力学的仿真分析和优化设计,研究结果在迎角机构实际运行中得到验证。     

基于试验方法的运动帆船帆翼空气动力性能研究

帆翼空气动力特性是帆船重要的性能之一,为了掌握帆船比赛中不同航向角时帆翼的空气动力特性,采用了缩尺比为1∶16的几何相似模型进行了单帆帆翼的空气动力性能试验研究,得到了不同航向角下帆翼的推力系数、侧向力系数随攻角变化关系和最大推力系数以及对应侧向力系数曲线。分析发现:在帆船航行中存在死角区,当航行角在此区域内不管攻角如何改变帆船都无前进推力,该帆翼的死角区为0°~10°;航向角小于40°时帆船航行不是理想状态;在航向角在40°~140°之间,最大推力系数随航向角增加而增加,对应侧向力系数则随航向角增加而减小。当航向角为140°时,最大推力系数是全过程中的最大值1.52,对应侧向力系数又是全过程中比较偏小的,所以,当航向角为140°左右时帆船有较理想的航行状态。试验结果和所作的结论,为帆船运动员在奥运会帆船比赛过程中帆翼调整提供了理论基础。     

伦敦奥运会帆船竞赛区域风的特征分析

帆船运动主要是靠风在帆上产生动力而推动船前进的运动项目,风是帆船运动最主要的条件。本文采用实验研究的方法,探索了伦敦奥运会帆船竞赛区域的风的特征,为我国帆船运动员徐莉佳在奥运比赛中有效地利用风和正确选择航线提供了有力的保障。     

帆船训练中伤害事故的致因及预防措施

帆船运动是一项风险性极高的户外运动项目。帆船运动员在训练时既要和对手对抗，又要和风浪斗争，这种特殊的训练环境，使运动员在训练中易发生伤害事故。因此，如何正确预防伤害事故的发生，已成为困扰帆船运动发展的一个棘手问题。本文通过对帆船训练过程中伤害事故原因的分析，提出正确预防伤害事故的措施与方法，以期为我国帆船运动的长远发展提供参考。     

PF-1级自航式模型帆船的制作

在中、小学开展的航海模型活动中，PF-1级自航式帆船模型是比较受欢迎的科技活动项目。“PF”是普及和帆船两个词组的第一个汉语拼音的字母。PF-1级自航式帆船模型是利用风力作为能源航行的模型船。它航行时不用电和燃油，并且比较经济，对环境没有污染。同学们通过自己制作一条PF-1级自航式帆船模型，不仅可以提高动手能力，而且还能激发参加科技活动的热情。国家体育总局对PF-1级自航式帆船模型的制作有以下一些规定：船体的最大长度不得超过500毫米；单体船，有一面前帆和一面主帆；前帆和主帆的总面积不得大于0．12平方米；不得安装任何光、声、磁、电等控制方向的设置。     

遥控帆船模型（一）

今年8月8日，所有中国人热切期盼的奥运盛会就将在北京开幕了。在众多的竞赛项目中，帆船比赛将在美丽的海滨城市青岛进行。帆船运动是航海技术与体育运动相结合的科技体育的典型项目，是人类凭借自身力量，利用大自然的成功例证。而遥控帆船模型是大帆船的缩影，它将风帆空气动力学、船体流体力学与无线电遥控技术、模型技术完美结合。参加遥控帆船模型竞赛如同真人操纵的帆船竞赛一样具有很强的对抗性，不仅可激发斗志，引发兴趣与爱好，而且从中能学到不少有用的知识，对开发，提高青少年的创造能力具有良好的作用。为此，从本期开始，本刊将连续介绍有关遥控帆船模型运动的相关内容。     

对帆船迎冲角的探讨

最佳迎冲角是帆船可以产生最大前进推力,从而获得最快的速度,也是帆船在竞赛中可占50％的效果。因此国内外优秀选手对迎冲角都有不同程度的研究与看法。迎冲角是帆船在行驶各种风向中,根据风速和水面情况的不同,选择并掌握的有利最佳迎冲角是非常重要的。本文采用迎冲角程序教学法进行教学,加速了运动员操作技能的形成和掌握,提高了教学效果,激发了运动员的训练课的兴趣。     

帆船帆板和足球运动员情绪唤醒水平的生理监测指标与评价研究

研究探讨了帆船帆板和足球运动员情绪唤醒水平的生理监测指标与评价。结果表明：对于帆船帆板和足球项目运动员，前额肌电值不能作为情绪唤醒水平变化的评价指标；手指皮肤导电性可以较好地反映帆船帆板和足球项目运动员的情绪唤醒水平；手掌心温度和手指端血容可以作为帆船帆板运动员情绪唤醒水平的敏感性监测指标；心率值的变化可以较好地反映帆船帆板和足球项目运动员的放松和兴奋两种情绪唤醒水平。     

Numerical investigation on trimming of a single sail in a regatta

In sailing regattas, the actions of sailboats are to meet, overlap, pursue, pass, anti-collide, and defend. The aerodynamic performance of a sail based on a numerical simulation method is reported in this study. The parameters affecting the sail’s aerodynamic force coefficients, namely sailing angle, attack angle, mast shape, pitch angle, and camber ratio, are analyzed. From the results, basic principles and corresponding tactics of sail trimming are discussed and recommended for the start, during the windward, running, and leeward legs, before the finish, and near the marks. Sailors in the regatta should decrease the interaction of air flows around the sail to increase the lift force. The sailing angle, attack angle, pitch angle, and camber ratio should be adjusted to the appropriate degree to speed the boat when it is balanced. Sail trimming tactics have been practiced by professional sailors in regattas during which they can be scientifically supervised to compete against each other at Olympic Games.     

前迎风行驶中船体相对平衡和越涌浪技术探讨

对帆船迎风行驶中船体相对平衡和越浪关键技术做了详实的分析。在帆船涌浪操作、实验结果和结论等部分中，直观而明确地阐述了越浪这一关键技术的要点。     

Physical requirements in Olympic sailing

Abstract

Physical fitness and muscular strength are important performance parameters in Olympic sailing although their relative importance changes between classes. The Olympic format consists of eight yacht types combined into 10 so-called events with total 15 sailors (male and female) in a complete national Olympic delegation. The yachts have different requirements with respect to handling, and moreover, each sailor plays a specific role when sailing. Therefore physical demands remain heterogeneous for Olympic sailors. Previous studies have mainly examined sailors where ‘hiking’ (the task of leaning over the side of the yacht to increase righting moment) is the primary requirement. Other than the ability to sustain prolonged quasi-isometric contractions, hiking seems to require significant maximal muscle strength especially in knee extensors, hip flexors and abdominal and lower back muscles. Another group of studies has investigated boardsailing and provided evidence to show that windsurfing requires very high aerobic and anaerobic capacity. Although data exist on other types of sailors, the information is limited, and moreover the profile of the Olympic events has changed markedly over the last few years to involve more agile, fast and spectacular yachts. The change of events in Olympic sailing has likely added to physical requirements; however, data on sailors in the modern-type yachts are scarce. The present paper describes the recent developments in Olympic sailing with respect to yacht types, and reviews the existing knowledge on physical requirements in modern Olympic sailing. Finally, recommendations for future research in sailing are given.     

Quantifying external focus of attention in sailing by means of action sport cameras

The aim of the current study was twofold: (1) to validate the use of action sport cameras for quantifying focus of visual attention in sailing and (2) to apply this method to examine whether an external focus of attention is associated with better performance in upwind sailing. To test the validity of this novel quantification method, we first calculated the agreement between gaze location measures and head orientation measures in 13 sailors sailing upwind during training regattas using a head mounted eye tracker. The results confirmed that for measuring visual focus of attention in upwind sailing, the agreement for the two measures was high (intraclass correlation coefficient (ICC) = 0.97) and the 95% limits of agreement were acceptable (between ?8.0% and 14.6%). In a next step, we quantified the focus of visual attention in sailing upwind as fast as possible by means of an action sport camera. We captured sailing performance, operationalised as boat speed in the direction of the wind, and environmental conditions using a GPS, compass and wind meter. Four trials, each lasting 1 min, were analysed for 15 sailors each, resulting in a total of 30 upwind speed trials on port tack and 30 upwind speed trials on starboard tack. The results revealed that in sailing – within constantly changing environments – the focus of attention is not a significant predictor for better upwind sailing performances. This implicates that neither external nor internal foci of attention was per se correlated with better performances. Rather, relatively large interindividual differences seem to indicate that different visual attention strategies can lead to similar performance outcomes.     

多参数帆船训练及监控系统的研制

介绍了多参数帆船训练及监控评价系统的原理、功能、创新性以及其应用。该系统首次集GPS、双轴倾角、风速、风向传感器及配套软件为一体,对帆船的纵倾角、横倾角、速度、位置、航向以及风速、风向等指标进行同步采集和实时监测,能同时对1到6名运动员的帆船运动状态进行同步监测和纪录。     

Indicators of sailing performance in youth dinghy sailing

Abstract

This study aimed to determine indicators of sailing performance in 2 (age) groups of youth sailors by investigating the anthropometric, physical and motor coordination differences and factors discriminating between elite and non-elite male optimist sailors and young dynamic hikers. Anthropometric measurements from 23 optimist sailors (mean ± SD age = 12.3 ± 1.4 years) and 24 dynamic youth hikers (i.e. Laser 4.7, Laser radial and Europe sailors <18 years who have to sail the boat in a very dynamic manner, due to a high sailor to yacht weight ratio) (mean ± SD age = 16.5 ± 1.6 years) were conducted. They performed a physical fitness test battery (EUROFIT), motor coordination test battery (Körperkoordinationstest für Kinder) and the Bucket test. Both groups of sailors were divided into two subgroups (i.e. elites and non-elites) based on sailing expertise. The significant differences, taking biological maturation into account and factors discriminating between elite and non-elite optimist sailors and dynamic hikers were explored by means of multivariate analysis of covariance and discriminant analysis, respectively. The main results indicated that 100.0% of elite optimist sailors and 88.9% of elite dynamic hikers could be correctly classified by means of two motor coordination tests (i.e. side step and side jump) and Bucket test, respectively. As such, strength- and speed-oriented motor coordination and isometric knee-extension strength endurance can be identified as indicators of sailing performance in young optimist and dynamic youth sailors, respectively. Therefore, we emphasise the importance of motor coordination skill training in optimist sailors (<15 years) and maximum strength training later on (>15 years) in order to increase their isometric knee-extension strength endurance.     

排球二传队员攻击能力的培养与实践

从二传队员加强攻击能力的必要性以适应排球运动发展的角度，谈新时期二传队员的选择；攻击意识和攻击性技术的训练与培养，并探讨了二传队员攻击能力的赛场实践。     

Aerodynamic drag and biomechanical power of a track cyclist as a function of shoulder and torso angles

The speed attained by a track cyclist is strongly influenced by aerodynamic drag, being the major retarding force in track events of more than 200 m. The aims of this study were to determine the effect of changes in shoulder and torso angles on the aerodynamic drag and power output of a track cyclist. The drag of three competitive track cyclists was measured in a wind tunnel at 40 kph. Changes in shoulder and torso angles were made using a custom adjustable handlebar setup. The power output was measured for each position using an SRM Power Meter. The power required by each athlete to maintain a specific speed in each position was calculated, which enabled the surplus power in each position to be determined. The results showed that torso angle influenced the drag area and shoulder angle influenced the power output, and that a low torso angle and middle shoulder angle optimised the surplus power. However, the lowest possible torso angle was not always the best position. Although differences between individual riders was seen, there was a strong correlation between torso angle and drag area.