山谷中潰壩衝擊水工結構物之現象探討

A study of the flow phenomena in a valley due to the dam-break flows on the hydraulic structures

陳宏顏(Hung-Yan Chen)

指導教授 ： 鄧志浩

中原大學/工學院/土木工程學系/碩士(2008年)

https://doi.org/10.6840/CYCU.2008.00396

摘要

以數值模擬方法研究山坡地型中，潰壩遭遇不同形式障礙物所造成之水面變化。此方法使用最小平方有限元素法 (LSFEM) 來求解淺水波方程式 (SWE)。潰壩部分之模擬，選用圓形潰壩、完全潰壩與部分潰壩，分別在山谷渠道中遭遇具有不同寬度、距離、間隙，及不同板牆數的障礙物。根據水體動能完全轉換至位能的觀念，我們利用撞擊至結構物的水深來計算水體對結構物的作用力。發現其碰撞後水位之壅高與障礙物及水之接觸面積有關。在增加了障礙物後，對渠道兩岸亦會造成更大之衝擊。此外，本研究利用靜水壓的觀念來計算水流撞擊於板牆上之作用力，並藉由最大碰撞水位乘以板牆寬度來概估板牆受力(F)，並且發現 (1) 在板牆兩側為封閉邊界時，實際之板牆受力為概估最大可能受力 (F) 之 90 % ，(2) 在板牆兩側為開放的狀況時則實際之板牆受力約為概估最大可能受力 (F) 之 40 %。
本文研究，不同障礙物所造成之影響與可能壅起之水體皆可有效的模擬，希望研究之結果能為水利工程之應用設計提供參考。

關鍵字

淺水波方程式 ； 潰壩 ； 最小平方有限元素法

並列摘要

In this study, we conducted a scheme of numerical simulation method to solve the water level changes of dam-break on the different hydraulic structures in a valley. Least-square finite element method (LSFEM) is used to solve shallow water equation (SWE).
Simulation of the dam-break flows in the cases of circular dam-break, fully dam-break, and partial dam-break propagate into hydraulic structures with different widths and opening intervals located downstream with various distances to the dam site in a valley channel. Based on the concept that the kinetic energy has been totally transferred into the potential energy, we adopt the water level on the structure to estimate the force of the water on the structures. The total force is calculated by the summation of the hydrostatic pressure with multiplication of the contacted area. The results show that the total force on the structures has close relation with the highest water level and the contacted area. The maximum possible force (F) on the hydraulic structures is computed by the highest water level times the contacted area. It is found that (1) the hydraulic structures with opening intervals embedded at both ends, the flows can only pass through the opening section, the estimated acting force will be about 90% of the maximum possible force (F); (2) for the hydraulic structures where the flows can pass throught the opening and pass over the sides of the structures, the estimated acting force will be about 90% of the maximum possible force (F) is about 40 % of the maximum possible force (F).
Based on the simulation of this study, the results can be used to the design and construce the hydraulic structures in the future.

並列關鍵字

least-squares finite element method (LSFEM) ； dam-break flow ； shallow water equation

參考文獻

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