So' do ve ng an h Hydroinformatics duoc gi6'i thieu cling vo'i cac iing dung da c6 tai Vi~t Nam tro g Iinh v u'c me hrnh h6a cac tinh to an dong chdy mat , xam nh ap man, chat lu'ong mro
Trang 1T,! -p chi Ti n h oc va Die u khi€n lio c , T.17, S 1 (2001), 85-88
M.B ABBOTT, TRUONG TUNG, VU HONG CHAu
Abstract A short description of th new disciplin Hydroinformatics is given, together with applications of Hydroinformatics to the fields of Vietnam:
- Surface water modelling
- Salinity intrusion modelling
- Water quality modelling
- Ground water modelling
Remarks on several interesting features ofcomputations are also included
Torn tlit So' do ve ng an h Hydroinformatics duoc gi6'i thieu cling vo'i cac iing dung da c6 tai Vi~t Nam tro g Iinh v u'c me hrnh h6a cac tinh to an dong chdy mat , xam nh ap man, chat lu'ong mro'c va mro-c ngarn Nhirrig d~c trung dang liru y trong cac tinh toan cling du'o'c de c~p cho timg me hlrih
1 KHAI QuAT VE HYDROINFORMATICS
Nhir ten goi cu a no, Hydroinformatics (xem [1] co the' hie'u la khoa hoc.ve cac phtrong phap ung du n g ki thuat tin hoc (informatics) v a truyen thong (communication) VaG c ac bai toan lien quan den mo! tr uo'ng nu'o'c Tuy mo'i chinh thtrc ra d2ri vo'i ten goi tren VaG dau th~p ky 90, nhrrng tie than cii a Hydroinformatics di co tir khoan 30 narn truoc do, chu yeu bao gam:
- Thuy hrc tin h to an (computational hydraulics)
- D9ng hrc hoc chat long (fluid dynamics)
- Cac phrrcmg ph ap so (numetical methods)
- Mo hrnh toan (numerical modelling)
Nhu:ng net chinh trong su' ph at trie'n cii a phiro'ng lnro'ng nay di du'o'c trlnh bay trong [1)
2, UNG DVNG CUA HYDROINFORMATICS VAo M9T s6 BAI ToAN
MO HINH HOA DONG CHA Y T~I VI~T NAM Trong cac noi dung cua Hydroinformatics, mo hinh toan ve dong chay la mot khau khorig the' thidu trong cac day ch uyen tinh toan qui hoach trong phan tieh thiet ke cac cong trl.nh thuy lo i,
thuy di~n, giao thong cti a Vi~t Nam
Chang han , trong viec danh gia khoi hrong mro'c va cac nguon t.ai nguyen mroc 0' cac dai ven bie'n, vide xac dinh phan bo cua t5ng hrorig mro'c qua c nh tir thrro'ng nguon dua v cimg vo it5ng lu'on mro c mira tai ch6 sinh ra doi hoi su p an tieh chi tiet ve cac dong chay khac nhau nhir dong
chay mat, d n chay n am va su: nhiem man cua cac song trong mira kiet , khi ma che d9 thuy van chiu anh hiro'ng manh me cua t.huy trieu,
Viec xfiy du'ng va su: dung UtC mo hinh nay la su' Ht hop cong sire cua nhieu nha toan hoc va cong ngh~ Vi~t Nam trong tat d 4 Iinh v1).'c tien than cii a Hydroinformatics, trong do co s1).'dong gop tir nhiing ngay dau cua hai tac gilt sau cua bai bao nay (Xem ket qui tinh t o an va qua t~c trong hl.nh 1)
2,1 Cac mo hinh toari chii yeu da dtro'c ap dung
2,1.1 Tinh toan dong chdy (mat.)
Day la mo hinh dtro c ling dung n hieu nhat va thanh cong nhat
Trang 286 M B ABBOTT TRUONG TUNG, vu HONG CHAU
mgjl
25
15
20
Tinhtoan
* - Th l( c do
Tram rlo Benn /f,;/o
I i nh 1 Tinh torin xfirn nhap man D~' in Quan L9 Phung Hiep
(So lieu narn 1983 Ngu itinh: Tru n Tung, Le Thu Vi~n)
a Chieu
Tren the gioi mo hlnh 3 chieu dii dtro'c a dung rong rai [Chau Au va My) Tro g khu vu'c
(Dong Nam A J , rno hinh 2 chieu khorig ho an chinh (pseudo-2D) d u'oc ap d ung d€ tinh lii son Me Kong (mo hinh SOGREAH) Mo hinh 2 chieu day d chi dung (;mire tinh vai bai toan don gian
C : Vi~t N am, mo hinh 1D diroc d.i tien d€ c6 th~ tinh lii tran vao cac khu c ira va ruong Day c6 th€ coi la lo ai l.5D Mo hinh 2 chieu dii diroc nghien ciu bo'i nhieu nha khoa hoc, cHn h an, Nguy~n An Nien va cac cong su' ,nhirn chua diro'c trie'n khai a dung vao cac bai toan c6 y nghia quan trong ,
b Phsiotu; t r in h
nhir sau
az aQ Ct E+{ 3 E Q {3 a Q Q I Q I
trong d6: E la do rang mat n uoc cua mat d.t ngan , E , la be ro g mat ruro c cii a tet dien dong
chay, t: thoi gian, Q: hru hro'ng , z: muc mro c, x: chieu dai, o ,{3: h~ so dieu chinh don n ang va dong hrong , g: gia toc trong tr o'ng , A: die tch m~t d.t ngan , c: h~ so Chezi, R : ban kinh thuy
hrc
c Ph uo r iq p lu i p so
Tron cac plnron p ap so, thuc te chi dung phtro'n phap sai p an, can cac phtrcng phap so
kh ac to ra it phi h p
d So ' ao iinh toan
So' do ifn 4 di~m cua Pressmann to ra U ' U vi~t hori h5.ncac sa do kh ac nen da danh diro'c d ia vi d9C ton tron bai toan nay
e T hnuit totui
2.1 2 T inh toan xarn n hap man
Day la bai toan du 'c ap dung than h cong chi sau bai toan dong chay mat,
a Phsionq trinh
H~ gom 3 phtro ng trlnh: 2 phuo ng trlnh dau n hir bai toan d n chay, them mot phuo'ng trlnh
bao toan IUQ'n man:
a s + 2as = ~ ~(ADaS) +qS
Trang 3tro g do, ngoai cac ki hieu di dU'a & phfin tru'oc, c c ki h ieu du'o c d ua them vao bao gom: S chi
him luong m udi, Q: hru ltro'ng d ng ch ay, D: he so khuech tan doc
b Ct ic phiir: kluic : giong nhir bai toan tren ,
e D if - e aii'm r ien g
Do co them phuo'ng trlnh tdi, bai toin co mot so dac di~m rieng:
- Anh hiro g cua dieu ki~n ban dau: tro g k i doi v i bai toin dong chay dieu kien ban dau se
klio g co tic d ng sau khoan 1 - 24 gio: tlnh toan, thl voi bai toin xarn n hfip man , an h hu'o'ng cu a
dieu kie n dau kh6ng he mat di trong suot qui trtnh tinh to an
- Tro g khi do chinh xac cua bai toan dong chay co the' rat cao (viti cm) thl di? chinh xac cua
tinh toan xarn nh ap man kern hon do tic du ng cu a kh uech tin so Mot so tic gi3.mroc ngoai cong
b cacph uo'n ph ap khic phuc hien tu'ong nay de'nang cao do chin h xac Tu nhien chua thay co tic gi3.nao o·mro c ta ap dung cac ph u'o'n ph.ip khil.cph uc nay
2.1.3 Tinh t.oan chat hro'rig mro'c
Tai Eo Nong n hiep v a Phit trie'n nong then, viec tinh toin chat hro'ng nuoc d ua tren m6
hinh The enhanced stream water quality models QUAL2E an QUAL2U CAS cua Hoa Ky (United
States Enviromental Agency) voi cac di).cdi~m chinh nhir sau:
a Ph uon q tr in h
a M _ a (AxD L 'fE ) _ a ( A xuC ) A ac s
tro g do: M Ii khoi Iiro'ng (mass: M), x: kho ang each (distance: £), t: thai gian (time: T ) , C: di?
dac (concentration: M £-::t Ax: dien tich mat dt (cross-sectio al area: £ ), D L: h~ so phan tin (dispersion coefficent: £ T - 1) , u: toc di? trung binh (mean velocity: £T - 1), s: sl l·tieu tan (external
source or sinks: MT - 1 )
b Ca e p hiin kh dc gio g nlnr bai toin dong ch ay mat v a xam nhap m an
2.1.4 Tinh toari mro'c rigarn
ve m~t mo hlnh,bai toin nuoc ngfim co khic biet C O ' ban sovo'i bai to an rnroc mat tro g khi
b ai toin ruro c mat dung cac phuo ng trin thuy hrc thi bai toan mroc ng am dung cac phuo ng trinh
thuy van Ii chu yeu
Diic die'm tren diL lam cho cac mo hinh 2D, 3D diroc su dung rong r ai doi voi bai toin mroc
ngam gio g nh u mo hinh 1Dch bai toin mro'c m~t
2.2 Cac phiro'ng phrip so
Co the' sli' dung mot trong cac ph irong ph ap sau:
1) Sai ph an hiru han (finite difference metho FDM)
2) Phan tu' hiru han (finite element method FEM)
3) Ph5 (spectral method SM)
4) So' do 19c(fiter scheme method FSM)
5 ) Ph an tl-bien (boundary intergral equation method BIEM)
Gan day, toc di? tinh toin co khuynh huan dtro'c cai thi~n nh o viec ap dung cac phu o ng ph ap
tinh toin song song tren cac h~ thong ph an tan B cbiet, viec gi3.i xfip xi h~ phuon trinh Saint
Vernant tren may tinh song song 3.0PVM (Parallel virtual Machine: [ 5 ] ) dil.co nhfing thrr nghiern
b oc dau
Nlu iti xe t :
Phuon phap 1 (FDM) du'o c dung ro g ril.i va ph5 bien, ke' d trong tinh tcan song song
Ph uo'n phap 2 (FEM) sau nhieu thrr nghiern, cac tic gi3.deu co chung nh an dinh FEM thich
h 'p cho ca bai toan ket cau xay d ung h n Ii tinh toin mroc
Cac phuo g ph ap khac chu yeu mang ynghia Iy thuyet,hoc thuat , it co y nghia thuc tien
Trang 42.3 U'ng dung
2.3.1 Bai t.oan dong chay (m~t)
Day la bai to an d u'o c n hien ciiu va d u'a vao tinh q i hoach thu 191tir nam 1969 tren may
Minsk22 Truo'n Dai h9C Th uy 191 va Vien Qui hoach thuy 1 1 Ii cac CO' q an di dau trong Iinh
vuc nay voi n hieu d6ng g6p tro g nhii:ng bu'o'c di dau tien cila cac can b<?khoa hoc nhir: Nguyen
Nhir Khue, Ng yen An Nien, Tran Duc Kh arn, Nguyen Van Sang, Le Xuan Quang, TrU'()'TIgTung,
- Thuy dien Ho a Bm h
- Tinh lii (d~c bi~t ch Dong bhg Cuu Long theo chi thi 99 TTg "song chung vo'i lii.")
2.3.2 Bai toan xarn nh:%p rnan
Ducc khoi dau b i Ban thu ky Me Kon (Ban k k), V61 s~'d6ng g6p cu a Vi~n Qui hoach thu
1 0i[Tru-o-ng Tung, Le Thu Vi~n) v a Vi~n CO'(Nguy~ Tat Dac) Ch ong trlnh nay dil dU'9'C tinh
toan de' phuc vu I~p qui hoach t5 g the' (Master plan) cu a Dong bang Me Kong
2.3.3 Bai toari c ha t hro'ng mro'c
V6'i su' tro' giup cu a Chinh phu Thuy Die'n (SIDA) bai toan dil du'o'c I~p va du'a vao tinh tcan
chua phen tai dong bang Me kong [Le Xu an Quang , Chu Thai Hoanh] va a nhi~m tai m<?tso son
Chat tinh to an a nhi~m la BOD, COD, N02, N03 ,
NO'i tinh: song Nhue v a m9t so song kh ac
2.3.4 Tinh toan mro'c ngam
Bai toan nay dil dto'c Tru-o g Dai h c Th uy lo i, Vien Qui hoach thuy 1 1, Cong ty Tu van Xay
dung thuy 1 1 u'ng d ung tir vai nam nay
Tren day mo i chl n6i den mot so irng dung tai B9 Nong nghiep v a Phat trie'n Nong than T'ai
c ac bo, n gan h khac nlur: Ciao thong, Xay dung', Khi tiro'ng 'I'huy van, Di~ cac bai toan ten cin
d cc suo dung nhieu v a thu:c su' la nhfing d ng g6p hieu qua
TAl LI:¢U THAM KHAO
[ M B Abbott, Introducing Hydroinformatics, J o urnal o f Hydr o inform a ties 1 (1) (1999)
[2] Truo'ng Tung va Pham Tran Nhu, Mo hinh h6a va phan mern tro g khoa h C moi tr tro'ng ,
[4] Cac bao cao khoa h9C n9i b9 cti a B9 Non nghiep va Phat trie'n nong than
[ 5 ] Le Quan va Ph am Tran Nine, Tinh toan song song: thuat toan so va may tinh, H il i thdo Pluit
Nluin l ei s au kh: s d n ay 12- 12 -2 000
Th J y loi v a Moi truoru) , Ho L an ( IR E).