單階自由跌水之數值模擬

Numerical Simulation of Unit step Free Overfall

陳建富(Chien-Fu Chen)

指導教授 ： 鄧志浩

中原大學/工學院/土木工程研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200126

摘要

摘要
本文以數值模擬方式探討單階自由跌水問題。其中將水面考慮為液氣接觸之二相流體的問題，我們係以流體體積法(VOF)為基礎來建立二相流問題的控制方程式。
本文利用最小平方有限元素法(LSFEM)來解控制方程式，一般有限元素法在求解自由水面的問題時，主要是以(1)固定網格或(2)非固定格網(格網隨時間改變)這兩大類為主，本研究主要使用第一類的方式。在本文中以不同的流量及跌水高度對跌水後射程長度、迴水區水深及能量變化等由於自由跌水所引發的相關問題，藉由數值模擬方式對這些問題作定量及定性分析，本研究與前人實驗與數值研究作比較，驗證效果良好，故對於具自由水面流場計算是一個良好工具。

關鍵字

單階自由跌水 ； 最小平方有限元素法 ； 二相流

並列摘要

ABSTRACT
This paper presents the numerical simulation of unit step free overfall. Two-phase flows model is applied for this study with the basis of volume of fluid (VOF).
Least-squares finite element method is used for solving the unified Navier-Stokes equations which governs both the fluid and gas phase. For trading the interface of two difference phase, fixed mesh (front tracking) simulation is coupled with the additional colour function. The simulation results are compared with the experimental data and other computational solutions, it shows very good agreement between each other. LSFEM provides a very good tool for simulating the flows with free surface.

並列關鍵字

Two-phase flows ； Least-squares finite element method ； unit step free overfall

參考文獻

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