Dòng chảy không ngừng sau vỡ đập.

Dòng chảy không ngừng sau vỡ đập. Trong quãng thời gian 1940 – 1950, có Kiến trúc máy tính của Von Neumann, lý thuyết trò chơi, và cellular automata, và McCulloch giới thiệu Mô hình thần kinh nhân tạo, Mạng nơron, perceptrons và classiffers.Phạm vi nghiên cứu của Điều khiển học
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Dòng chảy không ngừng sau vỡ đập. Journal of Computer Science and Cybernetics, Vol.22, No.3 (2006), 195—208 THE UNSTEADY FLOW AFTER DAM BREAKING* NGUYEN HONG PHONG1 , TRAN GIA LICH2 1 Institute of Mechanics 2 Institute of MathematicsAbstract. The following problems are presented: the unsteady flow on a river system and reservoirs,the discontinuous wave and unsteady flow after the dam breaking, numerical experiments for sometest cases and for natural Da river.T´m t˘t. B`i b´o n`y tr` b`y mˆ h` to´n hoc v` thuˆt to´n t´ d`ng chay khˆng d`.ng trˆn o ´ a a a a ınh a o ınh a . a a. a ınh o ’ o u ehˆ thˆ e o . ´ng sˆng v` hˆ ch´.a, s´ng gi´n doan v` d`ng chay khˆng d`.ng sau v˜. dˆp b˘ ng phu.o.ng ph´p o a o ` u o a . a o ’ o u o a a . ` ad˘c tru.ng, ´p dung t´ thu. nghiˆm sˆ cho bˆn b`i to´n kiˆ m tra c´ nghiˆm giai t´ v` c´c tru.`.ng a . a . ınh ’ e . ´ o ´ o a a e’ o e . ’ ıch a a oho.p v˜. ho`n to`n c˜ng nhu. khˆng ho`n to`n cua dˆp So.n La trˆn hˆ thˆng sˆng D`. . o a a u o a a ’ a . e e o. ´ o a INTRODUCTION There are several algorithms and softwares for calculating the unsteady flow on a river afterdam breaking. Some of them allow calculating the unsteady flow after gradual dam breaking,but cannot exactly determine the position of discontinuous front ξ and the height h of thefront ξ (see [8 - 11]). Other ones determine the accuracy of the front ξ and the height h, butthe unsteady flow is calculated only on one river branch after the instant dam breaking (see[1, 5, 6, 7]). In this paper the algorithm basing on the [5] permits to calculate the unsteady flow on theriver system, connecting with reservoirs after instant or gradual dam breaking. 1. MATHEMATICAL MODELLING The equation system describing the unsteady flows is established from the laws of conser-vation (see [1]) and has the following form: Qdt − ωdx = qdxdt, ∂S S Q2 Q|Q| P+ dt − Qdx = gω i − + Rx dxdt, (1.1) ω K2 ∂S Swhere h h ∂b(x, ζ) P =g (h − ζ)b(x, ζ)dζ, Rx = g (h − ζ) dζ, ∂x 0 0∗ This work is supported by the National Basic Research Program in Natural Sciences, Vietnam196 NGUYEN HONG PHONG, TRAN GIA LICH x - the coordinate along channel, t - time, q - lateral flow, ω - cross-section area, K - conveyance factor, h - the depth, i - bottom slope, b(x, ζ) - width on the distance ζ from the bottom, g - acceleration due to gravity, S - consideration region, Q - discharge, ∂S - boundary of S.1.1. One dimensional Saint—Venant equation system If the flow is continuous, from (1.1) we get the Saint—Venant equation system ∂Z ∂Q B + = q, ∂t ∂x ∂Q ∂Q ∂Z + 2v + B(c2 − v 2 ) = Φ, (1.2) ∂t ∂x ∂xwhere ∂ω gωQ|Q| ∂ω ∂Z 2 gωQ|Q| Φ = iB + v2 − = −B v − , ∂x h=const K2 ∂x ∂x K2Z - level of free surface,v - velocity,B - width of the water surface,c - celerity of small wave propagation. Equation ...