Luận án tiến sỹ " Tính toán dòng chảy vùng biển ven bờ - nước sông " docx

Cae nghi~n cll'u, khllosat va do d~c cac d~c tntng hili dudng hQc ngay ding nhi~u hdntr~n wng bien yen 1XJ.Tuy nhi~n, cac bai loan mo blah cho vungbie'nnay van con tltdngd6i it.. ye'u tr

TRU<JNGDl).IHOC KHOA HOC TV NmEN

V() THANH TAN

'fINI-I TOAN DONG CI-IAY

VUNG UIEN VEN nO - NUDC NONG

Chuyen nganh : H<liDLtdngHl)c

TOM TAT LU~N AN TIEN si V~T LY

TP H6 Chi Minh -2004

Vl)t Ly, trdi1ng D~i HQc Khoa HQc TV Nhit}n, D~i HQc Qu6c

Gia TP.HCM

NgtfC1ihtf(1ng d~n khoa hQc: PGS TS IJt}Quang To~i

PMn bit;n 1: PGS TS Dinh VAnu'u

PMn bit;n 2: TS Nguyen HOO NhAn

PMn bit;n 3: TSKH Phon VAn Hoijc

I

j

Lu~n an dtf<JcbaG vt? tnidc HQi B6ng chii'm lu~n an cii'p

Nha Ntfdc, hQp t~i: tnt<'fngB<;tiHQc Khoa HQc Tt! Nhien TP.HCM

VaG hie: 14 gi<'f30 ngay 24 thang 9 Dam 2004

C6 the am hieu lu~n an ~i thtfvit;n:

~ Khoa HQcT5ng H<JpTP.HCM

- Tnt<'fng B<;tiHQc Kltoa HQc Tt! Nltien TP.HCM

M(1 DAU

Khu v1!c bie'n yen 1XJDam Vi~t Nam c6 mQt vai tro ra-tquaD trQng trong nhi~u lanh v1!ckhac nhau Cae nghi~n cll'u, khllosat va do d~c cac d~c tntng hili dudng hQc ngay ding nhi~u hdntr~n wng bien yen 1XJ.Tuy nhi~n, cac bai loan mo blah cho vungbie'nnay van con tltdngd6i it Cae qua trlnh tltdngtae bie'n -1XJ 1£1nhfi'ng trd ng~i Idn eho cac bai loan mo blah Ngoai fa, ding c6the' ke' th~m blah d~ng du<'1ng1XJva s1!sii'd1}ngcac di~u ki~n bi~nd6i vdi mi~n tinh c6 bi~n rQng hudng v~ phia bie'n cling 1£1nhfi'ngkh6 khan kIDthi€t l~p mo blah

Phudng phap pMn tii'hfi'uh~n vdi tinh ~m deo trong vi~cthi€t k€ m~ng ludi to ra thich h~p d6i vdi khu v1!c c6 du<'1ng1XJbie'n phrtc ~p, c6 nhi~u dao nM M(ic du v&n tdn ~i nhfi'ngh~nch€dang ke ciia n6 d6i vdi cae bai loan mo blah thiiy dQng 11!c

Ngay nay, phudng phap pMn tii' hfi'u h~n dang du~c apd1}ngngay cRag nhi~u hdn vao cac bai loan thiiy dQng 11!chQc

bie'n, tU'nhfi'ngmo blah kich thudc nho, yen b<'1(lscandarani, 1993

- Le Provost, 1994- Kapolnai, 1996) cho d€n cae bai toaD hoao

hm d~i dttdng ba chi~u Dch thudc Idn (Greenberg, 1997).

L~n lu~t cac bai toaD mQt, hai va ba chi~u thllYdQng 11!chQc bien sii' d1}ngphudng phap phitn tii' hfi'u h~n du~c trlnh baytrong nQidung ciia lu~n an

Cung vdi vi~c ap d1}ngphudng phap so' tri ph~n tii'hfi'uh~nde' tinh toaD M th6ng hoan lttu gi6 mila ~i dai yen 1XJva th~m 11}cdia Dam Vi~t Nam, lu4n an nay con sii' d1}ngphudng phap tachmi~n khong giait cho bai toaD hoRn hm ba ehi~u

CHUdNG 1: TONG QUAN

1.1 GiO'ithi~u chung v~ khu vqc ven 1XIDam Vi~t Nam

Vung biin ven 1X7Dam Vi~t Nam du'<;1egidi h~n tit NhaTrang d6n dao Phd Qu6e du'QechQn lam khu vf{.enghi~n eU'uM

th6ng dong ehiy trong cae thang gi6 mua (tMng 1 va thang 7) vacae thang gi6 chuyin mUa (thang 4 va thang 10) Khu vf{.enghi~neU'uohm trong vUng kinh tuy6n tit 1O3~ d6n 111°E va vi tuy6n tit7,5~ d6n 13~ Df{.avao cae d~e diim v~ khi tu'Qngva hii van,ngu'Cfita ehia khu vf{.enay thanh ba vUng Vung 1 tit Nha Trangd6n Viing Tau; vung 2 tit Viing Tau d6n Ca Mau va vung 3 litvUngyen 1X7biin uty DambQ

1.2 Cac nghi~n CUDh~ th6ng dong chsy ven I.XI

Mc}t86 dQt khao sat va do d~e dong ehiy yen 1X7tit caetr~m do li~n t1;1edii du'Qeti6n hilnh Trong d6 e6 thi ki d6n cae

dQt "Dilu Ira khao sat tdng hf/p cae dilu ki~n tT!nhien t{li vung biin Kien Giang- Ca Mau" vitomua kho va mua mu'aDam1998

va ehuy6n khao sat vung biin Phan Thi6t vao thang 10/1999.1.3 MOt viti m6 hJnh tinh toaD ng~n CUDBi~n D6ng

Cae bili toaD mo hlnh eho vUng biin yen bCfkhong nhi~u

Do d6, cae k6t qua tinh loan eua roOhlnh Biin Bong va vjnh ThaiLan eung ea'p nhii'ngthong tin eiin thi6t eho bili loan yen 1X7

Mc}ts6 k6t qua tu'dng tf{.nhau tit cae lac gia khae nhau.Ching h~n mc}th~ th6ng dong eMy ~nh yen 1X7Dam Vi~t Namtit Phan Thi6t d6n Ca Mau (vUng 1 va vUng 2) hu'dng v~ Dam trong

tru'Cfnggi6 mUa dong - Me va hu'dng l~n bifc trong tntCfnggi6 muauty - nam; dong ehiy yen bCfvjnh Thai Lan (vUng 3) pMt triin

ye'u trong tru'(Jnggi6 mila dong - Me nhu'ngpMt trieD ~nh trong

tru'(Jng gi6 mila tay -Dam;

1.4 NQidung lu{in an va phddng phap nghi@ncoo

1.4.1 Cae n6i dung thu'c bien

M11etieu chinh: tlnh toaD h<%th6ng dong chciy gi6 trungblnh hai chi~u va ba ehi~u khu v1f.eyen b(J Dam Vi<%tNam tll' NhaTrang de'n vnng bien tay Dam va dao Phti Qu6c trong cae tru'(Jnggi6 mila d~c tru'ng bhng phu'dng pMp phin tit htru hc,tnvdi mc,tnglu'di du'~c xay d1f.ngg6m cae pMn to' tam ghic bit ky

Ngoai fa, phu'dng pMp phin tit htru hc,tncon du'~e ap d11ngvao bai toaD dong chay troi mQt chi~u vdi roOhlnh Ekman

Cae ke't qua tlnh toaD tru'£1ngdong chciy tu'dng !tng vdi caethang gi6 miIa d~c tru'ng va cae thang gi6 ehuyen mila du'~e th~hi<%ntren cae ban d6

1.4.2 Phu'dngpMp nghien eltu

Mi~n tlnh yen b(J e6 bien long rit rQng Phu'dng pMp tinhhai llin du'~e ap d11ng.LiD diu, vdi mi~n tlnh rQng hdn, khu vJ!.enam Bi~n Bong Ke't qua cua bai toan Dam Bi~n Bong du'~e sitd11nglam di~u ki<%nbien eho bai toaD yen b(J

Phu'dng pMp phin tit htru hc,tnd1f~eap d11ngd~ thJ!.Chi<%ndnh toaD eho cae bai toaD mQt chi~u, hai chi~u va ba chi~u Caemc,tnglu'di hai chi~u du'~e xiiy d1f.ngteen cd sd phep dJ!.ngtam giaeDelaunay, vdi thu~t toaD Delaunay Refinement

Phu'dng phap tach mi~n khong gian va phep bie'n ddi tQa

dQ khong th!t nguyen sigma du'~c ap d11ngde tinh dong ehciy bachi~u Bai toaD ba chi~u du'~e philn ra thanh cae bai toaD mQtehi~u theo phu'dng thing d!tng va cae bai toaD hai ehi~u theophu'dng ngang

CHUONG2:Cd Sa LY THuvET

2.1 H~ th6ng cae pbddng trlnb xua't pMt

Hc$th6ng cae phu'dng trinh xu(t pMt mo ta cae hoan h.tutrong d~i du'dng bao gdm cae phu'dng trinh bio loan dQng htc;Jng,bao loan kh6i htc;Jng,khue'ch tan mu6i va ehuy€n v~n entropi B6ivdi nhung chuy~n dQng kich thu'de ldn trong d~i du'dng, hc$th6ngphu'dng trinh xu(t pMt du'c;Jevie't trong hc$tQa dQ e~u (A, (j),R) e6d~ng r(t phtte ~p

2.2 Cae phep xa'p xi

Sa d~ng phep ehie'u leD ~t phing [3,cae phep g~n dungthuy tinh va phep g~n dung Boussinesq d€ du'a M cae phu'dngtrinh xu't pMt v~ d~ng ddn gian hdn

2.3 Cae m6 hlnb Hob toaD dong coy trong d{tidddng

2.3.1 Mo hlnh ba ehi~u

Phu'dng trinh bio loan dQng 1u'c;Jngd6i vdi thanh phhthing drtng rut l~i thanh phu'dng trinh thuy tinh va thanh pMn v~nt6e thing drtng du'c;Jetinh tit phu'dng trinh lien t~e Cae phu'dngtrinh chuy€n dQng e6 d~ng:

-

Thanh ph~n thing dli'ng eua veetd v~n t6e dong eMy t~iday bien Wbva dao dQng ro1,1'enUde l,;dli<;fCtinh tit cac di~u ki~ndQng hQc ~i day bien va tren ~t bien:

2.3.3 Phlidng phap pMn fa cua rod hloh ba chi~u

C6 nhi~u phu'dng phap pMn fa rod hlob ba chi~u ohhrodlia bai toaD v~ d~og ddn giiin hdo MQt troog 86 d6 la 81,1'tach cacthanh pMn nhroogangu va v cua dong cMy thanh cac thanh ph~n

(2.3)(2.4)

(2.6)

(2.7)

(2.8)

dong chay trung blnh U,v va cac dQ I~ch cua n6 Uf,v' quanh giatri trung blnh:

U,v duQc gQi la cac thAnhpMn chInh ap cua dong chay va uf, v'duQCgQila cac thiinh ph~n ta ap

Thanh ph~n chInh ap cua dong chay U,v va dao dQng mlfc

nudc ,duQc tioo tU'mo hlnh hai chi~u Cac thAnbpMn ta ap uf, v'duQc Hnh vdi budc th<'Jigian Idn bdn, c6 the ga'p mu<'JiI~n, so vdibudc th<'Jigian tinh cac thanh pMn chinh ap

2.4 Trao d6i rffi thing dUng

Thong thu<'Jng,ngu<'Jita danb gia M86 trao d6i r6i th~ngdd'ng Az tU'phudng trlnh dQng Dang r6i:

(A OE

) -!D oP-e

(2.10)

Trong sd dd Mellor- Yamadab~c 2, cac M s6 trao d6i r6i

va khutch tan r6i duQc tlnh to' pbudng trlOOditng cua dQng mlngr6i:

A{(:r +(:)'] - :D, : -e =0

(2.11)

Trong 8d dd Mellor - Yamada b4c 2V2, 1cichthudc r6i duQc

tinh tU'phudng trlnb chuyen dQng:

CHt1<1NG3: AP DVNG PHt1<1NG PHAP

TiNH TOAN DONG CHAY

3.1 BMtoan m()tchi~u

3.1.1 Thi€t lap bAiloan

Hc$th6ng cae ph\tdng trlnh xutt pMt eua bai toan m(>tehi~u Ozmidov e6 dl;\ng:

- Tl;\i m~t biin eho tr\tde tr\t{Jng\fng Stitt tie'p tuye'n gi6tr~n ~t biin:

u va v la cae thanh phdn ohm ngangeua v~nt&-edong ehay.

Sir d~ng ph\tdngpMp phdn ttl hii'uhl;\n,gia tri gdn dung eua cae thanh pMn v4n t6e dong ehay u va Y d\t<;1e xtp xi quanh

cae nut eua phdn tii':

V(n) -- VN""'1n,.(n) +vN+1 2<I>(n)

V.di c1>lk)va c1>r)la cae ham d~ng dng vdi ph~n ur (k):

)

San khi lien ke't ta't ea cae pUn tU'd~ ~o thanh m<}tma

tr~n loan eve cho ml,tng ltidi ta dti<;Jchai M phtidng trlnh dnh caethAnh ph~n v~

3.1.2 Cae ke't qua cua bai loan mot chi€u

1 TrtiClngdng sua't tie'p tuye'n gi6 kMng d5i: ke't qua tinhtoaD nMn dti<;JedtiClngxoAn 6e Ekman dng v"i cae vi de] khaenhau

2 TrtiClngh<;JptrtiClngdng sua't tie'p tuye'n gi6 thong d5iphtidng va de]!dn bie'n thien di€u bOa: cae kh6i nti"e l~i loon xoayhtidng eung chu ky eua trtiClnggi6 eung chi€u kim d6ng h6 d BAcBan C~u va ngti<;Jcl~i ~i Nam Ban C~u

B~u mut cac vecto dong chay cac t~ng ve Den mQt du'<Jng

eHip Khi T = To (chu ky dao dQng rieng cac kh6i nu'dc) du'<Jng

eHip trd thanh mQt du'<Jngiron co ban kinh r!t Mn.

3 Tru'{jng gio xoay hu'dng vdi chu ky T: cac kh6i nu'dctrong d~i du'ong ding xoay hu'dng cling chu ky vdi tru'<Jnggio Cac

d~u mut cua vecto dong chay t~o thanh mQt du'<JngtrOll.Ne'u gio

xoay hu'dng cung chi~u kim d6ng h6 thi dong chcly m~nh honnhi~u Tru'<Jngh<,1pT = To,vdi 811cQnghu'dngcua tru'<Jnggio vacac kh6i nu'dc trong d~i du'ong, dong chay cac t~ng co dao dQngcung pha vcsibien dQra't Mn

3.2 Phudng phap xay d\ffig m~ng Idm trong cae bai toaD haichi~u stt d\1ng phddng phap phdn ttt hii'u h~n

DlIa ireD ph§n m€m Triangle vcsi thu;%ttoaD DelaunayRefinement di xay dllng ~ng lu'oi dnh roan cho bai toaD DamBiin Bong va khu vllc yen b(J Dam Vi~t Nam voi goc d dinh tam

giac khong nM hon 27°.

M~ng lu'oi Dam Biin Bong g6m 1.602 diim nut, 3.031ph~n t11'va 4.633 c~nh M~ng lu'oi yen b<JDam Vi~t Nam g6m 947diim nut, 1.769 ph~n tti'va 2.716 c~nh

3.3 BM toaD roo hinh hai chi~u

3.3.1 He phu'ong trinh xu!t pMt cac di€u kien bien va di€u kienban dh

H~ th6ng cac phu'dng trinh xu!t pMt cho bai roan hai chi€u

ou(H+l;;) + ov(H+l;;) + ol;;=0

Bi~u ki~n ban d~u:

u(x,y,t = 0) = 0 v(x,y,t = 0) = 0 i; (x,y,t = 0) = 0

Bi~u ki~n bien:

Tren bien do, di~u ki~n bien tru'<;ftdu'<;feap d\lng eho eahai ~ng Iu'~iDamBien Bong va yen bCl:Y.nI Gl =0 (3.12)

Tren bien long, d6i v~i bai loan dong ebily nam BienBong, di~u ki~n bien pMt x~ Orlanski d6i v~i thiinh phh v~n t6epMp tuye'n du'<;feap d\lng eho ea du'Cfngbien phia bAe va phia Damcua ~ng Iu'~i:

-Cho tru'~e thanh ph~n v~n t6e pMp tuye'n v~i bien:

U =Ui <Pi+ Uj<Pj+Um<Pm V =Vi<Pi+ Vj<Pj+Vm<Pm

~=i;i <Pi + i;j q>j + i;m <Pm

trong d6 q>Iii ham d~ng:

(3.13)

<I>j=aj +bjx+cjY2L\ (3.16)

vdi aj= XmYi -XiYm ; bj= Ym - Yi;Cj=Xi - Xmva L\la di~n tich

cua m3i ph~n tit

Ap d',lUgph1.fdngpMp Galerkin cho cae ph1.fdngtrinh (3.8)

- (3.10) va san khi lien ktt cac ma tr~n c\tc bQd~ ~o ma tr~n toaD

c\te cho ~ng lu'di, eu6i ding, Mphu'dng trlnh trd thiloh:

(3.17)Cae phu'dog moh (3.17) d1.f<.1egilii bhog sai pMo lito theothCfigiao

vdi f=f~(I-Rf) la kich thudc r6i va fo =K(H+Z{I-~{I+ ~)]

la kich thudc r6i phan !lng trung dnh vdi K= 0,4 la hAng s6Karman

Thanh pMn th!ng dd'ng cua dong chay w du'<;1cdnh to'phudng trinh li~n D:tc:

au + av + aw = 0

ax ay az

Phudng trlnh d6i vdi dao dQng mtfc nu'dc:

at:" at:" at:" .

(3.20)

(3.21)Bi~u ki~n bi~n:

3.4.2 Su' tach mMn kMn!: !:ian troD!: m<>blnh ba chi~u

Thanh ph~n DAmngang cua dong chay trong d<;lidu'dng c6thl du<;1cxem 18 t6ng cua hai thanh ph~n:

{

U=Uh +uzV=Vh +vz

Do d6, phu'dng trlnh chuylo dQng ding du<;1ctach ra thanhcac phu'dog moh bai chi~u va mQtchi~u tUdngd'ng:

(3.24)

auh = -u au -Vau +fv-g at;_JL~ f1;p/dz+At Au

3.4.3 Phltdng phap bie'n d6i loa do sigma

Ph\fdng phap bie'n d6i tQa dQ sigma chI th~t s1f.pM h(jpcho khu V1f.cc6 dQ d6c day bi~n nM Tuy nhi~n, n6 cho mQtphltdng phap tinh ddn gian khi th1f.Chi<%nbAi loan ba chi€u S1f.apd~ng ph\fdng phap bie'n d6i tQa dQ sigma vito cac bAi toaD nlt~cDong vAkhu v1f.cven b() IAmQtphltdng phap tinh hi<%uqua cho cac

Y =y

I z-t;

0" H+t;

3.4.4 Ap dung phtfdng phap pMn tU'hU'uban vao hili toaD ba chi~u

Bili toaD ba chi~u Ia tc5ngh<jpcua cae bili toaD mt')tchi~u(g6m 6 clog sigma theo phtfdng thing d11'ng)vil cae bili toaD haichien 1£~ncae clog ding sigma ttfdng tl1nhtf hili toaD hai chi~u

So sanh giua cae bili toaD mQt va hai chi~u dtf<jctach ra tithili toaD ba chi~u va cae m6 hlob mQt chi~u 1£ong3.1 va m6 blobhai chi~u trong 3.2 c6 nhung khac bi~t:

Bai toaD mQt chien dtf<jctach ra kh6ng c6 thanh phin

l11c Coriolis.

Bid toaD hai chi~u du<Jctach ra khong c6 thanh ph~ntrao d6i r6i thing d\tng.

Slf tach mi~n trong bai toaD ba chi~u cho th!y hic$u\togcua bai toaD ba chi~u g6m t6ng cae hic$u«ng cua cae bili to<1nmQtchi~u va hai chi~u Trong d6, hic$u\tng mQt chi~u la sf! xoayhutJng dong chcly xu6ng cae t~ng san va hic$u«ng hai chi~u la slftrtt<Jtdong chcly ~i cae bCJr4n va sf! t<Jothanh cae xoay trong d<Ji

San khi ap dl,mg phudng pMp Galerkin d6i vtJi m6i phh

tir va lien ke't cae pMn tir cua tOaDbQ ffi<JnglutJi de ~o cae M

phudng mnh d(ic tntng, cae bai tOaDmQt va hai chi~u e6 dl.lngnhusan:

[A]~ a/(n) } {a~n-I) ~e + [A]~ a/(n-I) } [A ]{va/(n) } {a~n-I)}le + [A ]{va/(n-I) } (3.35)

va

[p ~ h/(n)} ~~n-I) }It + [p]~ h/(n-I) }

[pHvh/(n)}= ~~n-I) }It + [p ]{vh/(n-I) } (3.36)Trong d6,

[A] la ma tr4n vuong 6x6, cae ma tr4n cQt {Bu} va {Bv}

g6m 6 pMn tir.

[P] la ma tr~n vuong 16O2x1602va cae ma tr~n cQt {Qn}

va {Qv}g6m 1602 ph~n tir cho bai toan Dam Bien Bong so' phh

ttr tu'dog \tog cua chUng cho bai toan ven bCJl~n lu<Jtg6m 947x947

va 947

Thanh pMn v~n t6c thing d«ng ~i clog day du<JCHnh ttt

di~u kic$ndQnghQc:

aH aH

va ding du'<Jcap d1}ngphu'dng phap ph~n hi'hU'uh~n

Thanh ph~n v~n t6c thing d11'ng~i cac clog tren du'<Jcunhtft'phu'dng trlnh lien t1}c(3.20) va du'<Jcap d1}ngphu'dng phap saipMn hU'uh~n

Bi~u kic$nbien dQng hQc tren M ~t bi~n (3.21) du'<Jcapd1}ngd~ unh dao dQng m1!cnu't1cl;;va cling du'<Jcunh theo phu'dngphap ph~n tli'hU'uh~n

Bu't1cthiJi gian trong bai toaD mQt chi~u L\e Rho hdn bu'dc thiJi gian L\t trong bai toaD hai chi~u MQt vong l~p cua bai toaD

hai chi~u c6 nhi~u vong l~p bai toaD mQt chi~u Do d6, s1!tachmi~n khong gian d~ lam ro hic$u11'ngbai toaD ba chi~u ma contang t6c dQunh toaD

3.5 St1li~n k~t giila m6 binh Dam Bi~n D6ng va m6 binb ven 1XIDam Vi~t Nam

Bai toaD yen b(J Dam Vic$tNam du'<Jcth1!chic$nvdi di~u

kic$nbien long la ktt qua nMn du'<JCti'tbai toaD Dam Bi~n Bong

Chu'dng tdnh cho bai toaD Dam Bi~n Bong du'<Jcyilt vt1i

thu t1}cghi l~i ktt qua unh toaD ti'tng gi<'Jlen mQt ~p tin Gia tri

dao dQng m1!cnu'dc l;;ho~c thanh pMn v~n Wc phap tuytn Vntrenbien long cua bai toaD yen b(J Dam Vic$tNam c6 du'<Jcbhg cach

sd' d1}ngt~p tin ktt qua d~ dQCcac gia trj san ti'tng gi<'Jdnh cung

vdi cac ham nQiguy theo khong gian va thiJi gian

Cac bai toaD mQt chi~u va hai chi~u du'<Jcth1!chic$nmQtcach dQcl~p, cac thanh ph~n Ubva ~ tren cac clog cling du'<Jcth1!chic$ndQc l~p Den kha Dang l~p trlnh song song tren cac ~ng maytfnh la hic$nth1!cnhhm tang nhanh qua trlnh dnh toaD

(3.37)

CHUdNG 4:

Trong m6 hlnh hai chi~u, bu'<1cth<1igian dnh :1t= 6O0schobai roan Dam Bien E>6ngva :1t= 240scho bai loan ven b<1.Trongm6 hlnh ba chi~u, bai loan thing dti'ngmQt chi~u va bai tmin DAm

ngang hai chi~u c6 bu'<1cdnh I~n 1u'<;1tla :1r= 25s va :1t=6OOscho

bili loan Dam Bi~n E>6ng.E>6ivdi bai loan ba chi~u ven b(1 cae

bu'<1c dnh I~n 1u'<Jtla :1r = 30s va :1t= 240s.

4.1 Cae ke't qua cua b8i toaD hai ehi~u

T~i miii Cll Mau lu6n c6 mQt h~ th6ng dong char m~nhtrong cae thang gi6 mua Gifi'a Bi~n E>6ngva vinh Thai Lan lu6nc6 h~ th6ng dong chay xoay Stf xu!t hi~n cae xmly d~u lien quaD

d6n stf tu'dng lac eua tru'<1nggi6 va y6u 16 dia hlnh cua khu vf!.cva

e6 th~ giai thich sf!.xu!t hi~n cae xoay ireD cd sObao roan th6ng1u'<Jngnu'de trong d~i du'dng

H~ th6ng dong chay ~nh ven b(1 Dam Vi~t Nam tU NhaTrang d6n miii Cll Mau, hu'<1ngv~ Dam trong tru'<1nggi6 mua d6ng

- Me va hu'dng leu Me trong tru'<1nggi6 mua Hiy- Dam.

T~i khu vtfe Hiy- Dam fir miii Ca Mau dtn dao Phli Qu6e

c6 ffiQth~ th6ng dong chay m~nh vito thang 7 Tuy nhien, v<1itru'<1nggi6 nn)a d6ng- Me (thang I), dong ehiiy ndi d:iy l~i c6 giatri nM hdn rtt nhi~u

MQt xoay Rho hlnh thilnh ch~y dQe su6t b(1bien fir Nha

Trang d€n C~n Gi<1trong tru'<1nggi6 mua Hiy -Dam va sri tdn ~i

mQt dong chay nghich v~ hu'dng Dam ~i d:iy trong tru'<1nggi6 muaHiy- Dam