The Proceedings Fifth International Conference on Numerical Ship Hydrodynamics (1990) / Chapter Skim
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A Flood Control of Dam Reservoir by Conjugate Gradient and Finite Element Methods
A Flood Control of Dam Reservoir by Conjugate Gradient and Finite Element Methods
Pages 45-56
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From page 45... ...
Kawasaki Chuo University Tokyo, Japan Abstract A flood control of dam reservoir by the combined method of conjugate gradient and finite element methods is presented. For the numerical integration procedure, the two step explicit scheme originally presented by the authors' group was effectively used.
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From page 46... ...
Comparing with the results obtained by the dynamic programming technique, it is found that the present method is more suitable for the practical computation because the computer core storage in the present method is much smaller than that in the dynamic programming. This paper detected out a possibility that the control of the dam gate can be performed in the manner that almost the flat water elevation of the reservoir at the flood can be obtained on the condition that the hydrograph of the flood flowing to the reservoir is known in advance.
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From page 47... ...
To solve these equations, the time marching numerical integration scheme is introduced. The total time interval to be analyzed is divided into short time interval At by a plenty of time points n.
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From page 48... ...
4. Comoutational Algorithm The conjugate gradient method is successfully applied for the computational algorithm.
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From page 49... ...
Total time intervals 12sec. was divided into short time intervals 0.004sec.
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From page 50... ...
: O P T 1 M A L O U T F L O 14 -- : NORMAL OUTFLOW O _ _ _ O ~ A ~ ° / J o Lo ~ o o ~0.00 2-00 4.00 6.00 8.00 10.00 12.00 T I ME (SEC) Figure 6 Control discharge at the control point(model-1)
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From page 52... ...
On the most upstream side of the model the flood inflow discharge is specified and it is referred to as the flood inflow discharge point. The flood control point is set on the most downstream side where the dam is assumed to be equipped.
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From page 53... ...
The computed water elevations at the inflow, observation and control points are illustrated in Figure 17. The dotted lines show the computed water elevations without control.
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From page 54... ...
elevations computed at every referrence point show almost flat water elevation excluding the duration after the peak value of the flood. In the practical problem, it is usually seen that the maximum ability of the flow rate of the dam gate is limited.
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From page 55... ...
For the determination of the magnitude of the gradient vector, the line search method is shown to be one of the most efficient method of the analysis. Using the numerical computation based on the practical basin and estimated hydrograph, it has been cleared that the water elevation can be controlled by the discharge of the dam to reduce the peak value and to eliminate the secondary wave propagation toward the upstream of the dam reservoir.
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From page 56... ...
R.P.Stengel : "Stochastic optimal control", John Wiley & Sons, 1986 t11] M.Kawahara and T.kawasaki:"A flood control of dam reservoir by conjugate gradient method and finite element method", Proc.7th Int.Conf FEN in Plow Problems,pp629-634,1989 [12]
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