A Study on the Fluid Mechanics Performance of Aquatics Equipment

Transcription

1 MATEC Web of Conferences ( 05) DOI: 0.05/ matecconf/ C Owned by the authors publshed by EDP Scences 05 A Study on the Flud Mechancs Performance of Aquatcs Equpment Jan Jao Basc Teachng Cente Ocean Unversty of Chna Qngdao Shandong Chna Shugang Zhang College of Informaton Scence and Engneerng Ocean Unversty of Chna Qngdao Shandong Chna ABSTRACT: As a new knd of sport aquatcs have been accepted by general sports enthusasts. Sports such as rowng canoeng fn swmmng wndsurfng salng and water polo have become events of the Olympc Games. Compettons among countres are qute ferce. Based on the theoretcal foundaton of flud mechancs performance ths paper carres out an analyss on mechancal characterstcs of aquatc sports. Frst basc features of wndsurfng are studed n ths paper. Performance of wndsurfng changes wth ts parameters requrng a lot for wndsurfers. It can be known from varance analyss that the best performance of NP and a relatvely small resstance should be the drecton of salboard desgn. Meanwhle by buldng up a mathematcal model wth fuzzy comprehensve evaluaton and correlaton analyss t can be also found that the flud resstance characterstc s a key factor that nfluences the performance of wndsurfers. Besdes ths paper also takes nto account eternal factors ncludng the nfluences of regonal dfference on aquatc events. Dfferent regons wth varous geographcal condtons have dfferent nfluences on aquatc events. Keywords: aquatcs; flud mechancs; resstance characterstc; regonal dfference INTRODUCTION Wth the contnuous development of the scence and technology globalzaton n the st century tradtonal deas n Chna are constantly refreshed by new deas. The nature of scence s added not only n educaton but also n relevant aquatcs. Studes on the applcaton of flud mechancs n aquatcs carred out by scholars n Chna are presented as follows. Correspondng vewponts and conclusons are drawn based on the study on lteratures of scholars. In hs paper Research Progress of the Flud Mechancs of Aquatc Equpment n Chna Yong Ma carres out a specfc research on the flud mechancs of aquatcs n Chna based on the prncple of authentc academy and representatve data and provdes techncal references for the development of aquatcs n Chna. Ths paper ndcates that studes on aquatcs n Chna are earler than those n other countres. Aquatc events n our country now nclude wndsurfng canoeng skateboardng rowng and so on. Although preferable performances are obtaned n aquatc events nternatonally sklls reman to be further mproved. Studes on flud mechancs make aquatcs n Chna more scentfc and lay a sold foundaton for better performance. In the paper Applcaton Status of Flud Mechancs n Aquatcs n Chna Wetao Zheng analyzes aquatc events n Chna and ponts out the necessty of the applcaton of flud mechancs n aquatcs. The most mportant factor nfluencng the performance of aquatc events s resstance whch can be reduced as much as possble through studes on flud mechancs. For eample mprovements can be made n terms of the desgn of the skateboard and clothng of athletes so that the prncple of mnmum resstance can be satsfed. Thus aquatc events n Chna can be more scentfc wth better performance. Dongyan Zhang has made researches on aquatc Olympc events for a long tme and ganed suffcent eperence n ths feld. Several aquatc events n the Olympc Games and relevant performances of Chna are analyzed n the paper Development Characterstcs of Aquatc Olympc Events n Chna and the Analyss on Tranng and Management Factors. It s concluded that performances of aquatc events n our country are qute general. Man reasons nclude tranng mode of athletes selecton of equpment desgn of clothng nstructons of coaches and so on. Flud mechancs s rarely appled n aquatcs. Solutons are proposed n lne wth related problems. By usng research achevements of multple scholars for reference and conductng a quanttatve and analytcal comparson wth mathematcal methods ths paper specfcally analyzes the applcaton condton of flud mechancs n aquatcs n Chna based on the theoretcal foundaton of flud mechancs performance. It also analyzes mechancal propertes of aquatcs from the angle of wndsurfng ndcates key factors proposes relevant suggestons for related problems and provdes a drecton for the development of aquatcs n Chna. Ths s an Open Access artcle dstrbuted under the terms of the Creatve Commons Attrbuton Lcense 4.0 whch permts unrestrcted use dstrbuton and reproducton n any medum provded the orgnal work s properly cted. Artcle avalable at or

2 MATEC Web of Conferences ESTABLISHMENT OF MODELS Aquatc events manly nclude water bcycle dvng canoeng wndsurfng water polo etc. Aquatcs have been developng etremely fast n recent years brngng a great mpact on the Olympc Games and the Asan Games. It s also qute mportant to carry out studes on flud mechancs performance of aquatc equpment lke accessores of sngle/double rowng and sngle/double canoeng.. Research bass Flud mechancs s a dscplne that studes relevant laws and moton states of movng fluds and gases. The development and desgn of hgh-performance sports equpment can be provded wth a bass by applyng flud mechancs to the study on aquatcs equpment and by smulatng relevant flud propertes of aquatcs equpment wth theoretcal knowledge of aerodynamcs and flud mechancs as well as computer software lke CFD and CFX. Studes on flud mechancs are manly carred out from three aspects namely theory eperment and numercal smulaton. The three aspects complement each other and none can be dspensed wth. The workng process s presented below: Fgure. The man research method of flud mechancs Accordng to physcal characterstcs of athletes the mult-dscplnary desgn optmzaton (MDO) combnes physology bology knematcs sports medcne and other dscplnes together and couples the theoretcal knowledge of each dscplne so as to acheve the goal of performance research of aquatc sports equpment. The man feature s that comprehensve physcal qualtes of athletes are taken nto account wth the combnaton of multple dscplnes. Numercal smulaton s a computer technology wdely used n the flud mechancs research. Comprehensve analyses can be carred out on mechancal propertes of aquatcs equpment wth the fnte element method the fnte dfference method the dscretzaton method and so on. FLUENT s a wdely used method whch presents flud propertes of aquatcs equpment n the flow feld the temperature feld and the velocty feld wth cloud charts.. Wndsurfng.. A bref ntroducton of wndsurfng Wndsurfng orgnated from Hawa n the 980s where large sea waves provde wndsurfng wth more favorable wnd and wave condtons. Shapes and materals of salboard have evolved constantly snce then. Many scentsts have conducted specfc analyses on dynamcs and flud mechancs n order to make salboards more adaptable to the effect of wnd... Salboard desgn and the study on ts dynamcs propertes based on the varance analyss () Parametrc statstcs of salboard desgn The decsve factor of wndsurfng s the desgn of the salboard. Howeve our country has been short of resources due to the further eplotaton of resources snce 980s. Ths also stmulates scentsts n our country to carry out further studes on the new wnd energy. The research on the flud mechancs of wndsurfng starts to develop subsequently and stmulates aquatc sports to some etent. In ths pape the author takes Wndsurfer Mstral crcular and NP as eamples to study the dfferent flud resstance characterstcs of dfferent s wth varous parameters. The speed of a wndsurfng athlete represents the resstance. The faster the speed s the smaller the resstance wll be. Statstcal data are as follows: Table. Parameters of dfferent salboards Types Wndsurfer Mstral Crcular NP Area (m ) Boom (m) Mamum camber (m) Length (m) Heel(degree) () Establshment of the varance analyss model Varance analyss ams at consderng the nfluence of factors on ndees. Epermental results of the research obect are ndees. Control varables and condtons are factors. Two-factor analyss of varance should be consdered when there are two factors nfluencng the research obect. The mathematc model: suppose A has r levels A A A r and B has s levels B B Bs.The totalty of obeys the normal dstrbuton N( ) s n the level combnaton A B ). Results of t eperments k are recorded ( p.

3 ICETA 05 under A B whch obeys N( ) r s k t wth mutual ndependence. Decompose nto: k s k t k Where k ~ N ( ) wth mutual ndependence: r s s a rs s r r If there s no nteracton between two factors t the process can be smplfed. Suppose 0 so: s Now the model can be epressed as: r s 0 0 k ~ N0 s H H H Orgnal hypotheses are: : 0( r) : 0( s) : 0( s) When H 0 s satsfed: S A F r A ~ F( r ( r )( s )) SE ( r )( s ) F B When H 0 s satsfed: SB r ~ F( s ( r )( s )) SE ( r )( s ) Table. Calculaton results Squares sum of volatlty SS Freedom degree f Varance v F value Wndsurfer Mstral Crcular NP The data table of varance analyss can be obtaned through the analyss on data wth MATLAB. The analyss dagram of the above data s provded n fgure : It s concluded from the data analyss above that the NP s more fleble wth a heelng angle of zero. Propertes of the can be performed better wth smaller resstance. Hence t becomes the selecton of athletes n modern games. The crcular s short wth a large heelng angle. So t s preferred by amateurs and the prce s relatvely lower. The flat bottom can be also selected as the for compettons. But the propertes need to be further mproved. The NP has a smaller area and a lghter weght. The mamum camber of the boom s lower wth better balance degree. It s easly handled and performs well n compettons. The crcular has a larger area but t s hard to handle n a strong wnd due to ts smaller top and upper mamum camber p.3

4 MATEC Web of Conferences.3 A numercal analyss on nfluencng factors for performances of wndsurfers.3. Model of nfluencng factors of athletc performances based on fuzzy comprehensve evaluaton No matter what knd of sport t s the performance s mutually nfluenced by varous factors. And wndsurfng s no ecepton. Flud resstance characterstc physcal ablty of athletes psychologcal status of athletes sklled movement warmng-up eercses and propertes are sgnfcant factors for the performance of aquatc athletes. Here a fuzzy comprehensve evaluaton model of nfluencng factors for performances of wndsurfers s establshed and nfluences of the s factors for athletc performances are analyzed so as to determne the most mportant nfluencng factor and make preparatons for aquatc athletes. It can be known from a large number of documents that evaluaton ndcators show that nfluence performances of aquatc athletes can be classfed nto s categores: flud resstance characterstc physcal ablty of athletes psychologcal status of athletes sklled movement warmng-up eercses and propertes. U u u u m 3 6 m The set of evaluaton ndcators s {flud resstance characterstc physcal ablty of athletes psychologcal status of athletes sklled movement warmng-up eercse and propertes}. As for grades of the same system the man determnaton method s the epert evaluaton method. The set of grades n evaluatng the nfluencng factors for performances of wndsurfers s as follows: V v v v n 3 4 n The set of evaluaton grades of factors for performances of wndsurfers s {very good good general and bad}. The maor representaton of weghts s: w m 6 m 6 m m Here: Methods of determnng weghts of evaluaton ndcators manly nclude the analytc herarchy process and the normalzaton method. The normalzaton formula s: w C S C S n m Weghts obtaned through the above-mentoned method are: Evaluaton methods for the comprehensve evaluaton on the matr R manly nclude the epert evaluaton method the analytc herarchy process and the method of membershp degree functon. The epert evaluaton method s based on the questonnare survey and the statstcal results of epert evaluaton. There are certan errors n the results due to psychologcal factors. Here n order to make the calculaton results more accurate the method of membershp degree functon s adopted to determne the fuzzy relaton matr R. R R R R R R R T The evaluaton grade of the n th level: Fgure. Calculaton results p.4

5 ICETA 05 nu 0 u v vn v n n v u v n u n u v v The membershp degree of each evaluaton parameter can be calculated by substtutng data nto the above membershp degree formula. The fuzzy relaton matr R s constructed as follows: R W ( ) It s known that m R( r ) m n. Accordng to r r r n r r r n S w R m s s sn rm rm r mn The fuzzy udgment set S can be obtaned. Here s the fuzzy composton operator. The fuzzy operator s M ( ) namely: m sk mn r k k n The fuzzy udgment set S can be further obtaned whch s S ma S n that: M It can be known from M S S S n S S S ma n It can be concluded from the calculaton results that the flud resstance characterstc s a key factor for the performance. In addton the factors mentoned above are studed from the angle of athletes and salboard propertes. Physcal envronment factors lke temperature clmate and alttude also have an mpact on wndsurfers and ther performances..3. Model of athletc performance and flud resstance characterstc based on the correlaton analyss Wndsurfng has opened up a new feld of aquatcs. All the sport equpment can be used for aquatc lesure. Howeve dynamc propertes of salboard change wth the nfluence of resstance. In order to study the nfluence of resstance on dynamc propertes of salboard the correlaton analyss s adopted here to calculate the relatonshp between the two. Conclusons are drawn accordngly. The Pearson correlaton coeffcent s a knd of method of correlaton analyss. It s used to represent n n the smlarty between two varables whch can be obtaned through quanttatve calculaton. The formula s as follows: cov( X Y) E( X )( Y y ) ( X Y) E y X EX EX E X X So the Pearson correlaton coeffcent can be also epressed as: EXY EX EY ( X Y) E X E X E Y E ( Y ) It ndcates that the correlaton of the two s large or the two are closely related when the Pearson correlaton coeffcent of the two varables approaches or -. If t approaches the two are postvely correlated. If t approaches - the two are negatvely correlated. Here the ar resstance s represented by the wnd speed and the resstance of salboard n water s represented by water velocty. Meanwhle attrbutes of salboard are also ntroduced n order to compare the nfluence of resstance namely the comparson of the surface roughness of salboard. Data can be acqured as follows: Table 3. Data correlaton Speed per hour of Control varables salboard Speed per hour of salboard Pearson correlaton Sgnfcance (blateral) y Ar resstance Water Surface velocty roughness df 0 It can be seen that both the ar resstance and the resstance of salboard n water are the man factors nfluencng the speed per hour of salboard. For ths reason the moton process of salboard can be smulated wth the software CFD of flud mechancs. Velocty changes of salboard can be analyzed wth consderaton of ar resstance and water velocty so that studes on mechancal features of wndsurfng can be more thorough..4 Regonal dfference of aquatc events As for aquatc events regonal dfference s also an mportant eternal factor that should be taken nto account n the study on the flud mechancs. Economc development and envronmental features are dfferent n varous regons so the development stuatons of aquatcs and the flud mechancs characterstcs are dfferent as well. Gold medals dstrbutons of aquatcs of the th Natonal Games n dfferent regons are provded n the followng table. The nfluence of regonal factors s observed by comparng the gold medal dstrbuton n each regon p.5

6 MATEC Web of Conferences Fgure 3. The Natonal Games gold medal of the regonal water dstrbuton Table 4. Gold medals dstrbutons of aquatcs of the th Natonal Games n dfferent regons Rowng Canoeng Salng/Wndsurfng Southeast Northeast South Central Southwest 0 0 The statstcal dagram s drawn as follows n order to compare features of the gold medal dstrbuton n dfferent regons. It can be concluded from the hstogram n fgure 3 that there are large regonal dfferences n aquatc events. Thus the geographcal condtons and the envronmental factors n each regon are key factors that should be consdered n the study on the flud mechancs features of aquatcs. 3 CONCLUSIONS The analyss n ths paper s carred out based on the flud mechancs performance. The flud mechancs s an essental applcaton method as well as the theoretcal bass n the study on dynamc characterstcs of aquatc events. Therefore ths paper makes a bref ntroducton on the flud mechancs whch s the research bass of the paper. In addton the close relatonshp between the flud mechancs and the mechancal analyss on aquatcs s confrmed through the analyss on wndsurfng. The followng conclusons can be drawn through the establshment of a mathematcal model: The man reason that nfluences wndsurfng s the resstance characterstc; dfferent salboards wth varous parameters have dfferent flud mechancs features. It can be known from the varance analyss that the best performance of NP and a relatvely small resstance should be the drecton of salboard desgn. Fnally the restranng factor of aquatc events s taken nto account from the aspect of eternal factors namely the regonal dfference. Ths s also a key that should be consdered n the analyss of aquatcs wth flud mechancs. REFERENCES [] Ma Y. 0. Research progress of the flud mechancs of aquatc equpment n Chna Journal of Physcal Educaton. [] Ma Y. 0. The applcaton of mult-dscplnary desgn optmzaton n aquatc events Journal of Nanng Sport Insttute. [3] Zheng W.T. 0. Applcaton status of flud mechancs n aquatcs n Chna Chna Meetng. [4] Zheng W.T. 03. A lterature revew on sports engneerng at home and abroad Journal of Wuhan Insttute of Physcal Educaton. [5] Zhang D.Y. 0. A Study on the Numercal Smulaton of the Hydrodynamcs Performance of Rowng Paddle Wuhan Unversty of Technology. [6] L B.L. 0. Development Characterstcs of Aquatc Olympc Events n Chna and the Analyss on Tranng and Management Factors Qufu Normal Unversty. [7] He H.F. 0. A Numercal Smulaton of the Aerodynamc Performance of Sal Wavng Wuhan Unversty of Technology. [8] Ba K.X A Study on the Flud Mechancs Performance of Salboard and the Optmal Route Wuhan Unversty of Technology. [9] Lu L.N. 0. A Study on the Numercal Smulaton Method of the Aerodynamc Performance of Sal Wavng of 470 Salng Wuhan Insttute of Physcal Educaton. [0]Ge X.F. 0. Research progress of flud mechancs n physcal eercses Journal of Shandong Physcal Educaton Insttute. []Han J.R A study on the flud mechancs performance of salng and canoeng equpment Journal of Wuhan Insttute of Physcal Educaton p.6