美赛培训论文22998.docx

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1、Formation and Variation of the Great Pacific Garbage PatchAbstrractIn thhis ppaperr, wee buiild aa moddel bby uttilizze dyynamiic annalogg to expoound the formmatioon off thee oceann garbaage ppatchh.Our ddestiinatiion iis too traack tthe llitteer deebriss andd forrecasst itts fuuturee connditiions

2、to hhelp manaagingg it. Aftter tthe aanalyysis, we findd thaat the vveloccity of ttrashh allleviaates as ttime goess on. Traash ddoes its motiion iin twwo prrobabble wways, onee is due to rresisstancces ggivenn by sea wateer, aand aanothher iis duue too dammped viibrattion. By usinng cllassiic phhys

3、iccal ttheorries, we captture mainn mottivess proopellling trassh innto tthe SSouth PPaciffic GGyre. Thaats howw thee greeat ggarbaage ppatchh forrms.Accorrdingg to themmodell andd thee itss ressult, we formmulatte thhe moonitooringg proogramm.Compaared withh thee phyysicaal trruth, thee moddel aals

4、o has somee unssatissfacttory aspeects, butt it has somee refferennce.IntrooducttionWheree eveer iss thee worrlds larrgestt dummp? IIt iss loccatedd in the Paciific Oceaan, aboout oone tthoussand six hunddred kiloometeers wwest of CCalifforniia, callled the Greaat Paacifiic Occean Garbbage Patcch. A

5、cccordiing tto peertinnent dataa1, it iis teen miillioon toons oof deebriss littter thatt is piliing uup thhere, likke a plasstic soupp wheen peeoplee aree loookingg aheead. And 80 pperceent oof thhe trrash is ffrom mainn conntineents, 10 perccent conssistss of usedd netts orr othher ffishiing ttool

6、ss andd thee othher 110 peercennt off traash iis frrom ppassiing-bby shhips. Mosst off thee garrbagee isllandss aree in oceaanic gyrees.Noowadaays, a wiide vvarieety oof teechniical and scieentiffic pprobllems assoociatted wwith thiss debbris masss areecomiing tto liight. Butt unttil nnow, no oone c

7、can rreasoon ouutits coveeragee areea exxactlly annd thhe grreat econnomicc lossses ecollogiccal iimpacct annd thhe Paacifiic Occean Gyree hass cauused.Long-termm efffectiivemeethodds arre seearchhed tto obbjecttivelly chharaccteriizethe Gyree.The oceaan cuurrennt iss thee mecchaniismoff thee Greeat

8、 PPaciffic OOceann Garrbagee Pattch. In oour ppaperr, wee willltakke thhe soouth paciific oceaan gaarbagge paatch for exammple, foccusinng onn howw thee debbris littter ddriftts inn thee fluuid, asseemblees in quanntityy, diistriibutees undderthhe efffectt of oceaan cuurrennts iin.Afteerwarrds, in a

9、accorrdancce wiith oour mmodell,we projject proccessrreasoonablle suuggesstionns too monnitorr thee Gyrre, ttrackking its groowth.Assummptioons1. Regarrdlesss off timme annd geeograaphiccal pposittions immpactts onn thee speeed oof thhe occean currrentss, wee connsideer thhe sppeed as cconsttant val

10、uue.2. Accorrdingg to the datuum2, we desiignatte thhe sppeed of tthe wwest windd driiftvp1as 1.4 kmm/h, thaat off Perru Cuurrenntvp2as 1 km/hh, thhat oof thhe soouth equaatoriial wwarm currrent as vvp33 kmm/h, thatt of the nortth Auustraalia currrent as vp41.4 km/hh.3. Regarrd thhe fllow oof thhe c

11、uurrennts aas sttatioonaryy floow annd thhe seeawatter aas Neewtonnian fluiid, wwhichh meaans tthe vviscoosityy of the seawwaterr is consstantt.4. Consiider the leveel off thee seaa is in llaminnar fflow.5. The mmass poinnts mootionn in the sea can be iinfluuenceed byy thee oceean ccurreent nno maat

12、terr howw farr thee malll pooint is aaway fromm it.6. The mmass poinnts mootionn is syntthesiized by tthe ssub-mmovemment of pper ooceann currrenttregaardleess oof efffectts off othher ffactoors.The MModellIn ouur moodel, we willl utiilizee dynnamicc anaalog to eexpouund tthe fformaationn of the oce

13、ann garbaage ppatchh.The modeel suubstiituteesstraaightt linnes fforoccean currrentss whiich fform the gyre, inn thee moddelthhe orrienttatioon off thee strraighht liine rrepreesenttativve off thee floow diirecttion and the speeed vaalue retrrospeect tto thhe asssumpptionn No.4. SSequeentiaally, we

14、simpplifyy thee phyysicaal trruth as tthat showwn inn thee figgure 1. (Due tto thhe chhangee of the direectioon off thee Perru Cuurrennt onn passsagee, thhe siimpliifiedd moddel rreplaaces tow straaightt linnes, whicch arre off thee samme sppeed but diffferennt diirecttion, of the Peruu Currrentt.)F

15、igurre 1:the Disttribuutionn of the Oceaan Cuurrennts iin thhe Soouth Paciific OceaanThen,our modeel taalks overr howw thee oceean ccurreent eeffecct thhe maass ppointts moovemeent, moree speecifiicallly, tthe eeffecct onn thee vellocitty off thee dirrectiion pparalllel to tthe lline and perppendiic

16、ulaar too thee linne.Letss disscusss thee efffect on tthe mmass poinnts veelociity oof thhe diirecttion paraallell to the linee firrstlyy.Accorrdingg to the assuumptiion NNo.3 and No.44 andd thee rellativve innformmatioon3, wee cann desscribbe thhe occean currrent floww as one-dimeensioonal steaady

17、fflow. On the basiis off Navvier-Stokkes EEquattion showw bellowY meaans tthe mmass forcce off thee dirrectiion YY-axiis, iin ouur moodel; meeans the denssity of ssea wwaterr; meaans tthe kkinemmaticc visscosiity oof seea waater, , meaans tthe ddynammic vviscoosityy of sea wateer. WWe caan siimpliif

18、y tthe eequattion abovve annd geet thhe onne beelowInteggratee andd gett (1)So wee pluug toow booundaary ccondiitionns (22) shhown beloow innto tthe fformuula (1)integgral consstantt is deteerminned ,Sincee, soo(2)We caan maake aa connclussion thatt thee masss pooints veelociity iin thhe diirecttion

19、 paraallell to the oceaan cuurrennt iss thee samme ass thaat off thee oceean ccurreent.Seconndly we ffocuss on the masss poiint vellocitty inn thee dirrectiion pperpeendiccularr to the oceaan cuurrennts diirecttion.Havinng consuulteddsomee matteriaals4,we deecidee thaat thhe occean currrents immpact

20、t on floaaterss in the direectioon peerpenndicuular to tthe ooceann currrentts diirecttion is eequivvalennt too wavve daampedd osccillaationn.The fartther awayy froom thhe waave ssourcce, tthe wweakeer thhe osscilllatioon iss, whhich meanns inn ourr moddel tthat the smalller the floaaters veelociity

21、 iin thhe diirecttion perppendiiculaar too thee oceean ccurreents diirecttion is. And the veloocityy vallue iis (33)A meaans ooscilllatiion rrangee,; meaans tthe ddampiing ccoeffficieent, ; d meanns thhe diistannce tthe ppointt froom thhe soourcee or the linee; thhe evvoluttion meanns veelociity iis

22、 thhe ennergyys evoolutiion.The ddistaance d iss dettermiined by tthe fformuula bbeloww (4) Theen wee shoould deciide tthe eequattionss of the straaightt linnes of the oceaan cuurrennts. Accoordinng too thee figgure 1 annd ouur esstimaationn of the inteerceppts, the equaationns aree shoown bbelowwSo

23、 thhe diistannces thatt anyy poiint aaway fromm thee linnes aareSubsttitutting d1,d2,d3,d4,d5 forr d iin thhe foormulla (33), wwe caan geet thhe veelociitiess in the direectioon peerpenndicuular to tthe ooceann currrentts dirrectiions vc1, vvc2, vc3 , vc4 ,vvc5.Becauuse tthe ffarthher thhe pooints a

24、waay frrom tthe ooceann currrentt thee smaallerr itss vellocitty inn thee perrpenddicullar ddirecctionn is,we rrealiize tthe ssmalller iits vveloccity is tthe bbiggeer itts prressuure iis acccordding to Berrnoullli EEquattion4. Theerefoore, in tthe ddirecctionn perrpenddicullar tto thhe occean currr

25、ents fllowinng diirecttion,the forcce diirecttion is ooppossite to tthe vveloccity graddientt, diirectting to tthe lline.Now ffor aany ppointt in the coorrdinaate,tthe vveloccity is kknownn. Whhen iit mooves to aanothher nnew pposittion, thee vellocitty att thiis tiime, whicch keeeps the masss poiin

26、t mmovinng, iis deetermminedd by the new relaationnshipp bettweenn thee possitioon annd thhe liine.We esstabllish the coorrdinaate bbasedd on the latiitudee andd lonngituude, the origginall poiint llocatted iinthee poiint oof innterssectiion oof eaasterrn longgitudde 1550 deegreees annd sooutheern l

27、latittude 60 ddegreees, illuustraated in tthe ffigurre 1. v1, v2, v3, v4 andd v5 are the veloocitiies oof thhe cuurrennts, and () aree couunterrclocckwisse anglees beetweeen thhe diirecttionss of veloocityy andd thee X-aaxis axlee as showwn inn thee figgure 1.We diiscusss hoow evvery oceaan cuurrenn

28、t immpactts a masss poiint sseparratelly.A maass ppointt undder tthe weest wwind driffts immpactt,thee subb-vellocitties iin thhe diirecttion of XX-axiis annd Y-axiss aree (5)v1xmeeans the masss poiints veelociity iin thhe diirecttion of XX-axiis; vv1y meeans the masss poiints veelociity iin thhe di

29、irecttion of YY-axiis.Simiilarlly avvailaablefformuula ccan bbe goot beelow (66) (7)(8)(9)So unnder the actiion oof thhe fiive sstreaams oof occean currrentss, thhe veelociity oof X-axiss is (110)andthhe veelociity oof X-axiss is (11)Assumming thatt thee iniitiall possitioon off anyy poiint iis , we

30、 hhave testtifieed thhe veelociity aat anny tiime iis avvailaable, so the posiitionn of the poinnt att anyy timme iss alsso dooubtlless. We can solvve thhe vaalue by iinteggral.(12) Wheen thhe nuumberr of poinnts iis biig ennoughh to simuulatee thee traack oof thhe liitterr debbris,we ccan uuse mmat

31、laab too illlustrrate the pposittionss of poinnts,tthe ttendeency of llitteer acccumuulatiion, whiich bbeneffits desiign aand iimpleementtour planns too monnitorr thee oceann garbaage ppatchh. At lastt, wee simmulatte thhe prrocesss off thee acccumullatioon ass shoown iin thhe fiiguree 2 bbeloww.Fig

32、urre 2: thee Tenndenccy off thee Acccumullatioon off thee Littter DebrrisLitteer deebriss is far awayy froom thhe Gyyre aat thhe beeginnning, forr exaamplee, thhe liitterr dummped fromm thee Souuth AAmeriica ffloatts inn thee plaace nnear A. WWith the effeect oof thhe cuurrennts aand ttime goinng, i

33、it keeeps moviing , folllowiing tthe llaw wwe annalyzzed bbeforre, aalongg dettermiined eye locuus shhown in tthe ffigurre 2 untiil itt reaach tthe aarea E whhere the resuultannt foorce on tthe llitteer iss neaar too zerro. IIt iss thee samme ass thee littter in tthe aarea of BB andd D. But for C, o

34、our mmodell seeems aapproopriaate tto thhe pllace C, aand wwe wiill aanalyyze tthe rreasoon laater.Monittorinng Progrram1. In thhe arrea ooff tthe sshoree of the nortth off Ausstrallia (the zonee shoown iin thhe fiiguree 2 wwhosee x rrangees frrom -20000 to 0 annd y rangges ffrom 0 too 40000) aand o

35、of thhe weesterrn cooast of thhe Soouth Amerrica (thee zonne shhown in tthe ffigurre 2 whosse x rangges ffrom 80000 to 100000 annd y rangges ffrom 0 too 40000 ), wheere llitteer deebriss acccumullatess in a laarge amouunt oor thhe diistriict ppeoplle hiighlyy amaass, we ccan sset ffiftyy monnitorrin

36、g plattformms inn alll, whhich are undeer thhe coontrool off exppertss andd schholarrs whho wiill ddo meeasurremennt teermlyy to mastter tthe ddensiity aand tthe ddistrributtion of tthe ggreatt garbaage ppatchh gyrre inn thee paccificc oceean.2. In thhe zoone bbetweeen tthe ssouthh equuatorrial warm

37、m currrentt, whhose x raangess froom 0 to 88000 and y raangess froom 30000 tto 50000, and the westt winnd drrift, whoose xx rannges fromm 0 tto 80000 aand yy rannges fromm -10000 tto 10000,wwe caansett cerrtainn drooguess in everry unnit aarea, in ordeer too meaasuree thee amoount of tthe llitteer.3

38、. In addditiion tto thhe ittems,the moniitoriing sshipss shoould be aarrannged to tthe GGyre to ccolleect ssamplles, whicch innvolvvethee dennsityy, too forrecasstvarriatiion ttendeency by ddata stattistiics.4. With the ddevellopmeent oof thhe teechnoologyy, soome hhigh advaancedd toools ccan bbe de

39、eploiiedinn thiis fiield to mmonittor oor haandlee thee littter.The rresouurcinng thhe moonitooringg proogramm neeeds iisofffshorre pllatfoorms,droggues, thee monnitorring shipps annd soo on, thee monnitorring insttrumeents conssistiing oofsennsor unitts, aand uunitss forr colllectting and storring

40、dataa, unnits for proccessiing ddata, uniits ffor ccommuunicaationn andd rellativveauxxiliaary eequippmentts. Inn addditioon, aa larrge qquanttity of aand eexcelllenttmanppowerr ressourcce iss in demaand.IIt iss nott onlly hiigh ttech testiing ffacillitiees anndthee tallent of hhigh quallity but als

41、ooenviironmmentaal phhilossophyy thaat caan moonitoor orr eveen saave tthe hhumann beiings.Modell EvaaluattingAdvanntagees1. Throuughthhe annalyssis oof thhe maain rreasoon whhich causses tthe llitteer deebriss to movee in the sea,our modeel asscerttainss thaatit is tthe GGyre thatt driives the litt

42、ter ddebriis. TThen we ffind out the soluutionn to the probblem how to ddeterrminee thee vellocitty off masss poointss. By inteegrall, itt is easyy to desccribeethe tracck off littter debrris movvemennt annd itts poositiion aat anny tiime. Thatt is convvenieent ffor uus too forrecasst thhe exxtendd

43、,deensitty annd diistriibutiion.2. Compaared withh thee phyysicaal trruth illuustraated in tthe ffigurre 3 in tthe pposittion in wwhichh thee littter accuumulaates,it iis obbviouusly thatt ourr moddel aapprooachees too thee phyysicaal trruth.Figurre 3: thee Phyysicaal Trruth of tthe PPaciffic OOcean

44、n Garrbagee Pattch3. Our mmodell cann forrecasst thhe whhole garbbage patcchsdrifftagee, annd ottherwwise can simuulatee a mmass poinnts.Thaat wiill bbe ecconommicall to tracck soome mmass poinnts tto gaain tthe wwholee garrbagee pattch iinforrmatiion.LimittatioonsBy annalyssis iin deetaill, thhere

45、are alsoo somme deeviattionss cann be founnd beetweeen thhe reesultts off ourr moddel aand tthe pphysiical trutth. TTo soome ddegreee, oour mmodellsaccuuracyy is low, andd thee reaasonss aree lissted beloow.1. In ouur moodel, we takee thee dattum oof thhe soome mmain oceaan cuurrennts, but the compp

46、lex condditioons aare cchanggeablle inn thee seaa, thhe soourcee of the datuum maay bee unffaithhful.2. Our mmodell getts riid off thee efffect caussed bby tyyphooons ,rainnstorrms aand ootherr facctorss, buut inn facct, iit iss morre coompliicateed thhan tthat we cconsiider in tthe mmodell.3. Be reestriictedd by the datuum annd ouur teeam mmembeers abiilitiies, we ddont taake tthe AAustrraliaanconntineents efffectt on the nortth Auustraaliann currrentt intto acccounnt deeeplyy.Hennce,tthe ttrackk of the littter d