Manufactured Solutionを用いた高精度界面追跡法の検証

Verification of high-precision volume-tracking method with Manufactured Solution

伊藤 啓; 功刀 資彰*; 大島 宏之

Ito, Kei; Kunugi, Tomoaki*; Ohshima, Hiroyuki

本研究では、高速炉ガス巻込み現象を念頭に、渦流れによる気液界面の動的変形を対象としたManufacutured Solutionの開発を行う。まず、軸対称系において連続式と気液界面における条件式を満足する流速・圧力を決定し、また、界面くぼみが時間成長するとともにくびれが発生して気泡が千切り取られる挙動をモデル化した。基礎検証解析として正確な速度場を与えた上で動的界面輸送計算を行った結果、妥当な界面形状が得られたため、開発したManufactured Solutionが適切な検証問題となり得ることを確認した。

In this study, the authors develop a new manufactured solution with dynamic interfacial deformation due to a vortex, which is a simplified model of the gas entrainment behavior in a nuclear reactor. The manufactured solution is considered on an axisymmetric system and radial, circumferential and axial velocities and pressure are formulated to satisfy the continuity equation and the boundary condition on an interface. The interfacial dent grows with time and a gas bubble is generated when the lower part of the interfacial dent is pinched off. A preliminary simulation is performed on a coarse mesh to investigate the dynamic interfacial deformation on the velocity field given by the manufactured solution. As a result, a reasonable interfacial shape is simulated at each elapsed time, which implies the developed manufactured solution is a good problem to verify an interface-tracking method.