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Study on scale effect of impulsive breaking wave force for numerical simulation

冲击破波力尺度效应数值模拟研究

基本信息

批准号：
21K14256
负责人：
鶴田修己
金额：
$ 2.91万
依托单位：
National Institute of Maritime, Port and Aviation Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Early-Career Scientists
财政年份：
2021
资助国家：
日本
起止时间：
2021-04-01 至 2024-03-31
项目状态：
已结题

项目摘要

令和4年度は，非定常流をより高精度に解くため，前年度に開発した斥力型の安定化スキームに対して，信頼性の高い既存の粒子再配列スキームを組み合わせ，計算安定性及び精度の向上を図った．開発スキームは，重複粒子のみを対象に粒子ペア毎で粒子間距離を個別に調整する手法であるが，ここではスキーム間での機能の重複を回避すべく，近傍粒子配列の偏りを包括的に調整するParticle Shifting techniqueを追加スキームとして採用し，各スキームの機能が補完し合うように取り計らった．ベンチマークテストでは，各スキーム単体での使用時と比較してより高精度な計算結果が得られ，スキーム間の高い適合性・相乗効果を確認した．次に，衝撃波力の再現に求められる高解像度計算を実現すべく，流れ場に応じて高解像度粒子の追随・維持が可能な混合粒径モデルを新たに開発した．従来，粒子法では計算安定性のために計算粒子径を均一にすることが一般的であったが，近年においては，粒径ごとに離散化空間を分離・重複させて重合格子法に似た形で解像度可変計算を実現する手法が幾つか開発されている．しかし，離散化空間の転移・変形は容易でなく，必要解像度が局所的に時々刻々と変化する衝撃圧や砕波などに対しては，計算効率の維持が難しい．そこで本研究では，粒子間の微分演算モデルに対して粒子体積を考慮しつつ改良を施し，同一離散化空間で流れに応じて高解像度粒子を局所的かつ動的に維持させることが可能な完全Lagrange型の混合粒径モデルを開発した．さらに，砕波下の衝撃波力に対して本モデルを適用し，複雑流に対しても安定的に計算効率が維持させられることを確認した．また，二相流での異相界面にも本モデルを適用し，変形する異相界面に追随する形で任意の粒径（解像度）を維持しつつ安定的に計算ができることを確認した．

In 2004, the unsteady flow has a high-precision solution, and in the previous year, it was opened that the repulsive force was stabilized, and the existing particles were re-arranged with high reliability. The calculation of stability and accuracy were improved. Heavy particles are like heavy particles. The distance between particles is different from each other. The machine is capable of re-balancing avoidance cycles. The near-parabolic arrangement includes the adjustment of Particle Shifting technique devices, the addition of diesel engines, and the ability of each engine to complete the calculation of data collection in combination with each other. The results of high-precision calculation are satisfactory, and the results of high-resolution calculation are better than those of high-precision calculation. the results of high-resolution calculation are satisfactory, and the results of high-resolution calculation are better than those of high-precision calculation. in the second time, the wave force is calculated again, and the high resolution is calculated, and the high resolution particles follow and maintain the mixed particle size. The particle method is used to calculate the stability, the diameter of particles, the size of particles, the size of particles, the separation of particles, the separation of It is necessary to use the time limit of the local resolution station to improve the performance of the system, and to calculate the rate to maintain the temperature range. In this study, the differential calculus between particles is used to improve the performance of particles. The maintenance of the operation of the high resolution particle bureau of the same dispersion space flow may be a complete Lagrange mixed particle size operation. The shock wave force under the wave is used to determine the stability of the airflow, and the calculation rate of the stability of the flow is maintained. The phase interface of two-phase flow is widely used, and the phase interface of two-phase flow follows the calculation of arbitrary particle size (resolution) to maintain the stability.