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Prof. Zhou Peng was invited to attend the signing ceremony between bossini.X and the HK cycling team
Prof. Zhou Peng from AANTC participated in the signing ceremony between bossini.X and the Hong Kong Cycling Team, which took place on April 18th at the Jockey Club Lecture Theatre in the Olympic Building. During the event, Professor Zhou introduced the team's newly designed next-generation high-performance racing jerseys for the Hong Kong team. The collaboration between AANTC and bossini.X leveraged the research strength of the team in aerodynamics and cycling apparel development, combined with bossini.X's expertise in sports apparel manufacturing, to comprehensively optimize the cycling jerseys. Using 3D scanning technology, computational fluid dynamics simulations, and advanced wind tunnel testing, the team conducted multiple rounds of design optimization, focusing on factors such as fabric distribution and stretch ratios of the jerseys. The optimized cycling jerseys can reduce drag by up to 3% at racing speeds, giving the Hong Kong team a technological advantage in future competitions.
Post by , on April 19, 2024
The Chinese national cycling team athletes and coaches visited AANTC for communication and testing
Recently, the athletes and coaching staff of the Chinese national cycling team visited AANTC for communication and testing purposes. AANTC, through innovative cycling apparel design, posture optimization technology, and advanced full-scale sports wind tunnel testing, along with high-precision sensors, will provide scientific recommendations for the national cycling team athletes.
Post by , on April 19, 2024
世盃比賽版足球 傳射更準有數計
【明報專訊】今屆世界盃採用全新設計的足球Al Rihla，內藏的高靈敏度感應器為多個問題球如Ｃ朗的「上帝之髮」入球、日本翼鋒三笘薰底線助攻未有出界等，提供有力助證。雖然市面上買到的比賽版足球（$1199）未有這塊感應器，但與普通版（$259）相比，售價仍貴3倍有多，踢起來真的有什麼不同嗎？香港科技大學太古航天工程學教授兼空氣動力學和聲學實驗中心主任張欣及其團隊，將兩個足球放入低速風洞大比併，看看到底有什麼分別？ 在談足球設計之前，張欣先解釋影響足球飛行軌迹的一大因素——空氣動力學（aerodynamics），即物體在空氣中運動時所產生的各種阻力、側向力等。「雖然足球的射傳準確度與運動員的技術有最大關係，但當足球離腳後，影響它飛行軌迹的最重要因素便是空氣動力學。足球在空中飛行主要受兩方面影響，一個是重力，另一個是空氣流動所產生的力，皆影響足球的軌迹。」 他認為要解釋足球的空中運動，可以運用多種原理。首先是伯努利原理（Bernoulli's principle），「簡單來說，它說明了當空氣的流動速度愈快，壓力便愈小。因此如果空氣流經足球左右或上下兩邊的速度不一，它的飛行軌迹便會偏向流速快的一邊，而非直線飛行」。 張欣又解釋，空氣流過足球時，並不會完全貼着足球表面，而是在一定的位置後分離，「我們通常稱為流動分離，它會在足球後方形成一個壓力很低的區域，這是足球所受空氣阻力的一個主要來源。低壓區的大小，視乎當時空氣在足球表面流動的狀態是屬於層流（laminar flow）還是湍流（turbulent flow）」。在速度比較低的時候，空氣流動較有規則，分為一層一層，之間不會互相干擾，因而稱為層流；相反速度較高，或者存在表面擾動時，空氣流動就會變成較混亂及捲動的狀態，稱為湍流。「空氣動力學中有一個重要參數『雷諾數』（Reynolds number），可用於解釋當球體速度超過某一個臨界值，球表面的流動狀况會發生明顯改變，從有序的層流變成無序的湍流。相應的，流動分離點會往後移動，造成球後方的分離區域減少，阻力亦會隨之下降。」 要分析兩個版本世界盃足球在空氣動力學上的差別，張欣建議在科大空氣動力學和聲學實驗中心的低速風洞實驗室做測試，以量度在不同速度下足球的空氣動力學性能，「在風洞實驗中，我們可以在足球的表面黏貼一些纖維來觀察，氣流速度比較低的時候，可看出這些纖維擺動的方向比較一致，代表空氣流動處於層流狀態；當速度升高，纖維的擺動就變得雜亂無章，代表正受到湍流影響」。 足球周圍空氣流動狀態還可以通過煙流測試來顯示。風速較低時，空氣流動幾乎在足球的中央位置便開始分離；當風速增加，煙流在經過足球的中間點後仍會貼着球面移動，並在稍後位置才分離。先後測試過比賽版及普通版世界盃足球後，科大機械及航空航天工程學系研究助理教授周朋認為，「雖然我們看到比賽版足球的表面有很多結構，包括有較少的縫合坑紋及壓印紋理，但實際上，比賽版足球的空氣阻力與普通版在很多情况下分別不算明顯。」比賽版足球的球速不會與普通版足球有明顯差別。 不過他補充，比賽版足球的設計並非無用，實試中發現在大多數速度下，比賽版足球受到的隨機側向力都較普通版小，因此飛行路線不易改變。另一方面，在流動狀態發生改變的臨界速度區間內，比賽版足球的阻力變化都較普通版平緩。這些特點讓球員在長傳或遠射時，更準確控制傳球及射門位置。
Post by , on December 6, 2022
AANTC PhD student Kwan Pui Mok won the 7th HKASMSS Student Conference Award for Best Presentation
The 7th Hong Kong Society of Sports Medicine and Science Student Academic Conference and Asian Sports Medicine Association symposium was held at Hong Kong Science and Technology Park from December 4th to 5th. Prof. Xin Zhang delivered a presentation entitled "Advances in Aero-based Performance Sports Engineering Research". As a Panel member, Dr. Zhou Peng did the Bridging the Gap Between Developers and End Users: Discussion on "The Obstacles and Opportunities". AANTC doctoral student Tom Kwan Pui Mok presented an academic report entitled "Computational Fluid Dynamic Simulation for Track Cycling Strategies Development". AANTC used computational fluid dynamics to discuss the aerodynamic characteristics in the process of overtaking by single vehicle, which provided a basis for the formulation of overtaking strategy by single vehicle. The Presentation was awarded the 1st Prize of Oral Presentation -- Sports Innovations and Sports Technology. Congratulations, Tom!
Post by , on December 6, 2021
AANTC‘s project won the "Tianhe Star" Outstanding Application Award in 2021
At the national Supercomputing Guangzhou Center 2021 Supercomputing Innovation and Application Conference held on December 3, the "Tianhe Star" Outstanding Application Award was selected after layers of selection. The purpose of the award is to promote the integration and innovation of supercomputing and new technologies, and encourage users to explore and make full use of supercomputing resources to carry out research projects with scientific, economic, social and livelihood value. In 2021, the Center for Research in Aerodynamics, Acoustics and Noise Control Technologies (AANTC) won the award for its research project "Numerical Simulation and Drag Reduction Optimization design for Single-vehicle Aerodynamics". Over the past few years, the research team has applied advanced technologies from aviation and FORMULA 1 racing to competitive sports using advanced computational fluid dynamics methods. Special, through cooperation with Olympic team, recover the real model of elite athletes, at the same time, combined with advanced sports wind tunnel test measurement, the size of wind speed, cycling posture, cycling equipment, bicycle parts, motion and so on factors to evaluate the overall size of the wind resistance and optimization, to help athletes improve performance effectively, enhance the social influence. In addition, numerical calculation also provides the flow field distribution of different body parts, which helps to optimize the design of cycling clothing. In addition, the team examined the effect of wake characteristics on aerodynamics during overtaking between competitors, providing a basis for the development of effective race measurements. For now, the research team will continue to work with professional sports teams to study the aerodynamics of high-performance sports such as cycling and windsurfing (windsurfing). The results of the research will help coaches and athletes improve their training as well as carry out basic scientific research.
Post by , on December 6, 2021
Bluff body research reveals the mechanics of surface pattern on drag reduction and sound attenuation
In cycling sports, the aerodynamic skinsuit plays a significant role as reductions of the aerodynamic drag would improve athlete's performance. Recently, the research team explored the design principles of the aerodynamic skinsuit. By conducting cylinder wind tunnel tests within the range of cycling speed based Reynolds numbers, the research team found the sports fabric with longitudinal grooves can achieve a drag reduction over 50% and a maximum noise attenuation over 15dB. The research team also linked such variations to the near-field flow measurements in different flow regimes, revealing the fluid mechanics behind them. This research enables the design of the best aerodynamic skinsuit, helping athletes to improve their performance. The work is published in the reputed fluid dynamics journal Physics of Fluids. https://doi.org/10.1063/5.0070959
Post by , on November 15, 2021