非構造格子体系における気液界面での力学的釣合い条件の適切な定式化

Formulation of appropriate mechanical balance at gas-liquid interface on non-orthogonal mesh

伊藤 啓; 功刀 資彰*

Ito, Kei; Kunugi, Tomoaki*

ガス巻込み現象の直接数値解析を目的として、非構造格子系における高精度気液二相流数値解析手法の開発を進めている。本件では、歪んだ格子における高精度解析を達成するため、圧力と表面張力の適切な力学的釣合いを満たす定式化を導出した。本定式化では、表面張力ポテンシャルが定義されるとともに、圧力勾配の新たな計算法が用いられる。本定式化は液中の静止気泡の解析によって検証され、従来手法で発生した偽流速の発生を抑制することに成功した。

For the purpose of direct simulations for gas entrainment (GE) phenomena, we are developing a high-accuracy gas-liquid two-phase flow simulation method on non-orthogonal meshes. In this study, appropriate formulations satisfying a mechanical balance between surface tension and pressure were derived to achieve a simulation with high-accuracy on distorted meshes. In the formulation, a surface tension potential was introduced. In addition, a new formulation to calculate a pressure gradient was introduced. Finally, the new formulations were verified by calculating a stationary gas-bubble in liquid. As a result, the present method succeeded in eliminating perfectly spurious velocities induced by conventional methods.