Dl).IHOC Qu6c GIA TP. H6 CHI MINH
TRU<JNGDl).IHOC KHOAHOC TV NmEN

V() THANH TAN
, " ?
'fINI-I TOAN DONG CI-IAY
, ~ , , ~
VUNG UIEN VEN nO - NUDCNONG
Chuyen nganh : H<liDLtdngHl)c
Mii 86 : 1.07.07
TOM TAT LU~N AN TIEN si V~T LY
TP. H6 ChiMinh -2004
Cong trinh hoan thanh t~i: Bc) m6n V~t Ly MOi Trd<tng, khoa
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 VAnHoijc
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
VaGhie: 14 gi<'f30 ngay 24 thang 9 Dam 2004
C6 the am hieu lu~nan ~i thtfvit;n:
~ Khoa HQcT5ng H<JpTP.HCM
- Tnt<'fngB<;tiHQc Kltoa HQc Tt! Nltien TP.HCM

1.1 GiO'ithi~u chung v~ khu vqc ven 1XIDamVi~t Nam
Vung biin ven 1X7Dam Vi~t Nam du'<;1egidi h~n tit Nha
Trang d6n dao Phd Qu6e du'QechQnlam khu vf{.enghi~n eU'u
M
th6ng dong ehiy trong cae thang gi6 mua (tMng 1 va thang 7) va
cae thang gi6 chuyin mUa(thang 4 va thang 10). Khu vf{.enghi~n
eU'uohm trong vUngkinh tuy6n tit 1O3~ d6n 111°Eva vi tuy6n tit
7,5~ 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 Trang
d6n Viing Tau; vung 2 tit Viing Tau d6n Ca Mau va vung 3 lit
vUngyen 1X7biin uty DambQ.
1.2 Cac nghi~n CUDh~ th6ng dong chsy ven I.XI
Mc}t86 dQtkhao sat va do d~e dong ehiy yen 1X7tit cae
tr~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
- CaMau" vitomua kho va mua mu'aDam1998
va ehuy6n khao sat vung biin Phan Thi6t vao thang 10/1999.
1.3 MOtviti m6 hJnh tinh toaD ng~n CUDBi~n D6ng
Cae bili toaD mo hlnh eho vUngbiin yen bCfkhong nhi~u.
Do d6, cae k6t qua tinh loan eua roOhlnh Biin Bong va vjnh Thai
Lan 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 1X7DamVi~t Nam
tit Phan Thi6t d6n Ca Mau (vUng 1 va vUng2) hu'dngv~ Damtrong
tru'Cfnggi6 mUa dong - Me va hu'dngl~n bifc trong tntCfnggi6 mua
uty - nam; dong ehiy yen bCfvjnh Thai Lan (vUng3) pMt triin
3
ye'u trong tru'(Jnggi6 mila dong - Me nhu'ngpMt trieD ~nh trong
tru'(Jng gi6 mila tay - Dam;

trong d~i du'dng bao gdm cae phu'dng trinh bio loan dQnghtc;Jng,
bao loan kh6i htc;Jng,khue'ch tan mu6i va ehuy€n v~n entropi. B6i
vdi nhung chuy~n dQng kich thu'deldn trong d~i du'dng,hc$th6ng
phu'dng trinh xu(t pMt du'c;Jevie't trong hc$tQa dQe~u (A,(j),R) e6
d~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 dung
thuy tinh va phep g~n dung Boussinesq d€ du'a M cae phu'dng
trinh 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 phh
thing drtng rut l~i thanh phu'dngtrinh thuy tinh va thanh pMn v~n
t6e thing drtng du'c;Jetinh tit phu'dng trinh lien t~e. Cae phu'dng
trinh chuy€n dQnge6 d~ng:
00 00 00 00 1 Op. ac. g a
~ / a
(
00
)
-+u-+v-+w fv= g jpdz+- A - +A Au
Ot Ox. Oy Oz Po Ox. Ox. Po Ox.z Oz ZOz t
Ov Ov Ov Ov 1 Op. ac. g a
f
~ / a
(
Ov
)
-+u-+v-+w-+fu= g pdz+- A - +AtAv
Ot Ox. Oy Oz Po Oy Oy Po Oy Z oz ZOz

-a+U ax+v oy -fv=-p;:- ax -g ax- Po(H+l;) ifax dzdz+
'tS 'tb
+ x x +Al~u
Po(H+l;) Po(H+~)
av av av 1 ape 8l; g
J
/;
J
/;api
-at+uax +v ay +fu=- Po ay -gay PO(H+l;)-HZ ay dzdz+
'ts 'tb
+ y y + A ~V
l
Po(H+l;) Po(H+l;)
au(H + l;) + av(H + l;) + al; = 0
ax ay at
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 ohhro
dlia bai toaDv~ d~og ddn giiin hdo. MQt troog 86 d6 la 81,1'tach cac
thanhpMn nhroogangu va v cuadongcMy thanhcac thanhph~n
(2.3)
(2.4)
(2.6)
(2.7)
(2.8)
6
dong chay trung blnh U,v va cac dQI~ch cua n6 Uf,v' quanh gia
tri trung blnh:
u=u+ui V=V+Vf (2.9)
U,v duQcgQila cac thAnhpMn chInh ap cua dong chay va uf, v'

A{(:r+(:)'] -:D, :-e =0
(2.11)
Trong 8d dd Mellor - Yamada b4c 2V2,1cichthudc r6i duQc
tinh tU'phudng trlnb chuyen dQng:
D(q2p)=~
(
K oq2P
)
+EIPf Az
[(
8u
)
2 +
(
fJv
)
2
]
+ ! Dz api
}
-e (2.12)
Dt Oz q Oz 1 Oz oz Po oz
-
Cac h~ s6 trao d6i r6i Az.trao d5i khutch tan Dz:
Az =lqSM
Dz =lqSH'
(2.13)
7
CHt1<1NG3: AP DVNG PHt1<1NG PHAP
PRAN Tit HOO ~N VAo CAC MO HINH

u va v la cae thanhphdnohmngangeua v~nt&-edongehay.
Sir d~ng ph\tdngpMp phdn ttl hii'uhl;\n,gia tri gdn dung
eua cae thanhpMn v4n t6e dong ehay u va Y d\t<;1extp xi quanh
cae nut eua phdntii':
U
-(1) -
U
<1>(1)+ U <1>(1)
- 1 1 2 2
U-(n) - U <I>(n)+ U <I>(n)
- N.l N+1 2
v(z,t=O) = 0
y(l) - v <1>(1)+ v <1>(1)
- 1 1 2 2
-
V
(n) -
V n,.(n) + v <I>(n)
- N""'1 N+1 2
8
V.di c1>lk)va c1>r)la cae ham d~ng dng vdi ph~n ur (k):
c1>lk) = zk+l-z va c1>~k)= Z - Zk (3.5)
L L
Ap d\lDg phtidng phap Galerkin. m3i pUn td' dti<;Jebi~u
di~n dtfdi ma tr~n:
[
L/
3
L/
]{

l
-A (Vk+l-Vk)-Lf
(
Uk+Uk+l
)
/6 13 Vk-l z OZ zk L 6 3
1<+1
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 cae
thAnh ph~n v~
r
t6e u va v rieng bi~t e6 dl,t
~
~hti san:
[A] U}={Bu} va [A] VJ={BJ (3.7)
Dtfa c c ai€u ki~n bien vao M (3. ) va chung dti<;Jcgiiii
bhng sai philn tie'n theo thCligian dng vdi mMbtide l~p.
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 tinh
toaD nMn dti<;JedtiClngxoAn 6e Ekman dng v"i cae vi de] khae
nhau
2. TrtiClngh<;JptrtiClngdng sua't tie'p tuye'n gi6 thong d5i
phtidng va de]!dn bie'n thien di€u bOa:cae kh6i nti"e l~i loon xoay
htidng eung chu ky eua trtiClnggi6. eung chi€u kim d6ng h6 d BAc
Ban C~u va ngti<;Jcl~i ~i Nam Ban C~u.
9
B~u mut cac vecto dong chay cac t~ng ve Den mQtdu'<Jng
eHip. Khi T = To (chu ky dao dQngrieng cac kh6i nu'dc) du'<Jng
eHip trd thanh mQtdu'<Jngiron co ban kinh r!t Mn.
3. Tru'{jnggio xoay hu'dng vdi chu ky T: cac kh6i nu'dc

-+u-+v-+fu=-g-+ - +AfJ)v,
ot ox oy oy Po(H+(,) Po(H+(,)
10
ou(H+l;;) + ov(H+l;;) + ol;; =0
ox' oy ot
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 ea
hai ~ng Iu'~iDamBien Bong va yen bCl:Y.n
I Gl =0 (3.12)
Tren bien long, d6i v~i bai loan dong ebily nam Bien
Bong, di~u ki~n bien pMt x~ Orlanski d6i v~i thiinh phh v~n t6e
pMp tuye'n du'<;feap d\lng eho ea du'Cfngbien phia bAeva phia Dam
cua ~ng Iu'~i:
(3.10)
(3.11)
a<p a<p
-+c -=0
at P an
B6i v~i bai toaD dong cbily yen bCI,do da c6 cae ke't qua
tU'bai loan nam Biin Bong nen mQt trong hai di~u ki~n bien
Dirichlet du'<;fcap d\lng de tinh toaD:
-Cho tru'~e thanh ph~n v~n t6e pMp tuye'n v~i bien:
Vo(x,y,t)IG2= f(x,y,t) (3.14)
- Cho tru'dcdao dQngmlfc nu'dcbien tren bien:
i;(x,y,t)lo2=g(X,y,t) (3.15)
3.3.2 Ap dung phu'dngpMp phh to'hifu ban vao bai toan mOhlnh
hai ehi~u
Cae thanh ph~n v~n t6c dong eM y trung blob u, v, dao

(
av
)
-+u-+v-+w-+fu=-g jpdz+- A - +A Llv
at Ox Oy f}z oy PoOy z & z & £
(3.18)
Tru'CJngnhi~t - mu6i d1.f<.1eeho tr1.fdctU'cae tili li~u. H~ s6
nhdt r6i th£ng dti'ngd1.f<.1etinh trong di~u ki~n bO qua stf trao d6i
khutch tao nhi~t
-mu6i:
A, =£'.1(::J' + (:: r
(3.19)
12
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 hAngs6
Karman.
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 dQngmtfc nu'dc:
at:" at:" at:" .
-+u-+v-=w khl z=t:"
at ax ay
(3.20)
(3.21)
Bi~u ki~n bi~n:
T~i m~t biln:
Cho tru'dcd'ngsutt ti€p tuy€n gi6 ~i m~t biln t: va t~:

-w au
at a Zaz az
avh=-uav -vav -fu-gat;_JL~
f
1;p/dz+AtAV
at ax ()y ay Po By
z
avz =~
(
A av
)
-w av
at a zaz az
Cac ph\fdng trlnh (3.26) va (3.28) d\f(jcgiii b~ng bai loan
mQt chi~u thing dltng va cac ph\fdng trlnh (3.25) va (3.27) d\f(jc
giiHb~ng bili toaDhai chi€u n~m ngang.
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(jp
cho khu V1f.cc6 dQ d6c day bi~n nM. Tuy nhi~n, n6 cho mQt
phltdng phap tinh ddn gian khi th1f.Chi<%nbAi loan ba chi€u. S1f.ap
d~ng ph\fdng phap bie'n d6i tQa dQ sigma vito cac bAi toaD nlt~c
DongvAkhu v1f.cven b()IAmQtphltdng phap tinh hi<%uqua cho cac
mo hlnh ba chi€u.
Th1f.c hi<%nphep bie'n d6i d, tit b€ m~t bi~n z =t; de'n day
bi~nz =- H c6 tQadQkhong thlt nguy~n d =0 vAd =-I:
13
I
X =x
I
Y =y

va cae bili toaDhai chi~u:
aluh' , auf 1auI I al<;
- =-u - -v -+fv -g
ae axl ay' axl
0 , 1 0 al I
- g(H + <;)Ja~ dcrl + JL JQx ~dcrl + At !:1.u' (3.33)
Po cI ax Po d 00
al Vh' I (}V, , (}vI I al <;
-=-u v fu -g
ae &/ ayl ayl
0 I , 0 I I
- g(H + <;) Ja~ dcrl + ~ JQy a~ dcrl + At !:1.v' (3.34)
Po ",' ay Po cI 00
3.4.4 Ap dung phtfdng phap pMn tU'hU'uban vao hili toaDba chi~u
Bili toaDba chi~u Ia tc5ngh<jpcua cae bili toaD mt')tchi~u
(g6m 6 clog sigma theo phtfdng thing d11'ng)vil cae bili toaD hai
chien 1£~ncae clog ding sigma ttfdngtl1nhtfhili toaDhai chi~u.
So sanh giua cae bili toaDmQtva hai chi~u dtf<jctach ra tit
hili toaD ba chi~u va cae m6 hlob mQtchi~u 1£ong3.1 va m6 blob
hai chi~u trong 3.2. c6 nhung khac bi~t:
Bai toaD mQtchien dtf<jctach ra kh6ng c6 thanh phin
l11cCoriolis.
15
Bid toaD hai chi~u du<Jctach ra khong c6 thanh ph~n
trao d6i r6i thing d\tng.
Slf tach mi~n trong bai toaD ba chi~u cho th!y hic$u\tog
cua bai toaDba chi~u g6m t6ng cae hic$u«ng cua cae bili to<1nmQt
chi~u va hai chi~u. Trong d6, hic$u\tng mQt chi~u la sf! xoay
hutJng dong chclyxu6ng cae t~ng san va hic$u«ng hai chi~u la slf
trtt<Jtdong chcly~i cae bCJr4n va sf!t<Jothanh cae xoay trong d<Ji

d1}ngd~ unh dao dQngm1!cnu't1cl;;va cling du'<Jcunh theo phu'dng
phap ph~n tli'hU'uh~n.
Bu't1cthiJi gian trong bai toaDmQtchi~u L\e Rhohdn bu'dc
thiJi gian L\ttrong bai toaD hai chi~u. MQtvong l~p cua bai toaD
hai chi~u c6 nhi~u vong l~p bai toaD mQtchi~u. Do d6, s1!tach
mi~n khong gian d~ lam ro hic$u11'ngbai toaD ba chi~u ma con
tang t6c dQunh toaD.
3.5 St1li~n k~t giila m6 binh Dam Bi~n D6ng va m6 binb ven 1XI
Dam Vi~t Nam
Bai toaD yen b(J Dam Vic$tNam du'<Jcth1!chic$nvdi di~u
kic$nbien long la ktt qua nMn du'<JCti'tbai toaDDamBi~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'tnggi<'Jlen mQt ~p tin. Gia tri
dao dQngm1!cnu'dc l;;ho~c thanh pMn v~n Wcphap tuytn Vntren
bien long cua bai toaD yen b(J DamVic$tNam c6 du'<Jcbhg cach
sd'd1}ngt~p tin ktt qua d~ dQCcac gia trj san ti'tnggi<'Jdnh cung
vdi cac ham nQiguy theo khong gian va thiJigian.
Cac bai toaD mQtchi~u va hai chi~u du'<Jcth1!chic$nmQt
cach dQcl~p, cac thanh ph~n Ubva ~ tren cac clog cling du'<Jcth1!c
hic$ndQcl~p Den kha Dang l~p trlnh song song tren cac ~ng may
tfnh la hic$nth1!cnhhm tang nhanh qua trlnh dnh toaD.
(3.37)
17
CHUdNG 4:
CAC KET QuA TINH TOAN vA NH!N XET
Trong m6 hlnh hai chi~u, bu'<1cth<1igian dnh .:1t= 6O0scho
bai roan DamBien E>6ngva .:1t= 240scho bai loan ven b<1.Trong
m6 hlnh ba chi~u, bai loan thing dti'ngmQtchi~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(1cae

Mite nulk
-
Ifmh4.10:DOngehiytrungbinhvaml/enlillethdng7
19
Tht!e nghi~m HnhtoaDvdi hai di~u kic;nbien Vn(x,y,t)eho
tru'de va ~(x,y,t) eho tru'de dO'i.ydibai toaD yen bCl.Trong do, cae
thanh ph~n v~n to'e phap tuye'n Vn(x,y,t) va dao dQng mt!e mtde
~(x,y,t) tren bien long du\1erot tU'tai li~u Hnh eua bai loan nam
Bi~n Bdng. Ke't qua nh~n du'<jeeho thty di~u ki~n bien vdi dao
dQngmt!c nu'de~(x,y,t) du'<jeeho tru'dctren bien co dQ6n dinh eao
hdn.
4.2 Cac k~t qui cUa bai toaD ba chi~u
V~n sii' dt}ngdi~u ki~n bien dao dQng mt!e nu'de ~(x,y,t)
du'<jerot tU'tai li~u tinh loan dong ehay Dam Bi~n B6ng vao bai
loan yen bi1.
Khu vt!c tU'eii'a sdng H~u Giang de'n miii Ca Man ludn co
mQt M thO'ngdong ehiiy ml}-nh.Dong ehay ~ng ~t dl}-tde'n
31,5emls vao thang 1 va khoang 23,5emls vao thang 7.
Dong chay tl\ng m4t
tbiing 1
H'mh 4.30: Dong chdy tIlng milt thang 1 ven b(j nam Viit Nam
20
H'mh 4.40: Dong chiy tilng mijt thang 7 ven bu nam Vwt Nam
Hai m6 hinh hai chi~u va ba chi€u ddng nhit cho k€t qua
tudng t1fnhu nhau v€ hudng, v4n t6c dong chciy ding nhtt dao
dQngmlfc mtdc. Tuy nhien, slfkhae bi~t cM ytu gifta hai m6 hinh
tlnh d thanh ph~n v4n t6e tl1lDgbiBb khi c6 dong ehciy clng m~t
Phat tri~n ~nh.
4.3 So sanh klt qua v8i cae tAi Ii~u tinh tmin kluic
Nhii'ngdi~m phu h<;1p:

v2gH
giac chi mang mQt
ynghla tu'dngd6i.
Sf! 6n djnh eua ~ng lu'~i tam giac phq. thuQcnhi~u vao
di~n tfch eua cae phh tii'va dQs~u day bi~n. MQtso'm~ng lu'~idii
du'<;1cthie'tke'ma trong d6 sf!hdn kern v~ di~n tich eua cac ph~n tii'
e6 th~ l{;nde'n khoang tir vai ch1,lcde'n vai tram Idn ph1,lthuQcvao
dQs~u day bi~n.
22
4.5 Cae h\1neh6 ena phddng ph3p tinh
Phu'dng phap pMn tIt hii'u vAncon c6 nhung nhu'<,1cdiim
quaDtn;mgla kh6i lu'<Jngtinh tmin va th<1igian tinh r(t IOnso vdi
cae phu'dngphap sai phiin hii'uh~n.
Di kh4c pht}ctlnh tr~ng nay, c6 thi sIt dt}ng cae phu'dng
pMp xtt ly ma tr~n di nit ng4n th<1igian tinh hay sIt dt}ngphu'dng
pMp tach mien to.'bai loan ba chien thanh cae bai toaDmQtchien.
511ap dt}ng cae di~u kit$nNeumann va pMt x~ Orlanski
lam cho bai loan c6ng k~nh vi them mQt vong tinh toaD cho cae
pMn tIt tren bien va xu(t hit$n nhi~u sai so' trong qua trlnh tinh.
MQt~ng lu'dicac tam giac b(t ky tren bien long g~y Den sl1phU'c
~p trong vit$cap dt}ng cac di~u kit$nbien nay, th~m chi, khong
thi ap dt}ng du'<,1c.Do d6, di ap dt}ng du'<Jccac di~u kit$n
Neumann va.pMt x~ Orlanski cAnphai thitt kt l~i ~ng lu'disao
cho cac phSn tIt c6 kich thu'dc tu'dng d6i den d~n ~i bien long.
M~c du m~ng M1i da du'<Jcdy dJ1ngl~i nhu'v~y nhu'ngvAnkhong
lam giam sl1phU'ctC;1Ptrong qua trlnh ap dt}ngchUngva.obai toaD
mo hinh.
511ke'th<,1pcac phu'dngphap tinh, sai phiin hii'uh~n cho bai
loan flam Biin Dong (ho~c ca Biin Bong) va pMn tii'hii'uh~n, vdi
tinh HnhdQngtrong sl1thitt l~p ~ng lu'di, cho bai loan yen b<1c6