X: he sd karman
4.2.Tinh toan kiem dinh mo hinh
a l hng sd, T Q, T^ l nhiet do mt dt v khf quyen.
4.2.Tinh toan kiem dinh mo hinh
Md hinh dugc ki^m nghiem tir cac thdng sd dau vao don gian dén phiJc tap d^ danh gia đ dn dinh va tin cay cua md hinh. 6 day chi danh gia thii nghiem bang sd. Nghla la md hinh tfnh theo cac sd lieu d^u vao Ax, Ay, Az,At, khac nhau nham xac dinh do dn dinh md hinh va phat hien sai sd khuyéch tan sd.
Sau day ta xet mdt vai trudng hgp lam vf du:
Trudng hap I:
Cho mien tfnh L^ = Ly = L^ = 400m
k, = k^ = k^ = 20 m-/s; k, = k,, = k,, = 0.0001m-/s
Ax = Ay = Az = 40m; so di^m chia ludi m^ = n^ = j^ = 11 At = 2s, sd budc thdi gian tfnh TT = 200
Dieu kien ban d^u: t = 0
u = 0, V = 0, w = 0, 0 = 2 9 3 \ , p = 1000 mb,
q = 0.014 kg/kg, p= 1.2kg/m' Dieu kien bien:
Mat phang yOz tai X = 0, u (l,n,j) = 4m/s, 0(l.n,j) = 2 9 3 \ p(l,n,j) = lOOOmb q(l,n,j) = 0.014kg/kg
Mat phang xOz tai y = 0 v(l,n,j) = 0
Mat phang xOy tai z = 0: p (m,n,l) = 1000 mb
0 (m,n,l) = 2 9 3 \ , q(m,n,l) = 0.014 kg/kg
Cac mat bien con lai — = 0 (f co the la u, v, w, 9, q, p).
da
Ket qua tfnh van toe b diem giua mien u(6,6,6) = 3.06 m/s Trudng hgp 2:
Dfl lieu vao nhu a Uirtmg hop 1, chi thay Ax = Ay = 20m, Az = 40m.
Ket qua tfnh van tdc d giua mien: u (11,11,6) = 4.88m/s
Trudng hap 3:
DO lieu nhu trong trudng hgp 1, chi thay L, = 200m,
TT = 800, Ax = Ay = 10m, Az = 20m, At = 0.5s. Két qua tfnh van tdc d giOa mien u(21, 21, 6) = 4.3 m/s Két qua tfnh van tdc d giOa mien u(21, 21, 6) = 4.3 m/s
Qua 3 VI du tnnh bay d tren cho thây: