面向连续动边界问题的高效RBF动网格方法

An Efficient RBF Dynamic Mesh Method for Continuous Moving Boundary Problems

  • 摘要: 针对连续动边界问题(如烧蚀、流固耦合)中动网格更新效率低、网格质量易恶化的问题,本文基于径向基函数(RBF)法提出了两种高效鲁棒的动网格改进策略。其一,结合改进贪心算法(支持多点添加与最小距离约束)以加速控制点筛选,固定缩放因子简化参数设置,并引入少量拉普拉斯光顺以修正局部畸变;其二,基于单元拓扑关系实现位移的局部化分层传播,通过设置位移阈值避免对微小位移节点的冗余调整,并辅以全局光顺保证网格平滑性。球头圆柱烧蚀算例表明,所提方法在显著提升计算效率的同时,能保持良好的网格质量,并可成功耦合热流-温度-烧蚀多物理场程序,完成400秒的烧蚀过程模拟,从而为连续动边界问题提供了一种高效、稳定的动网格解决方案。

     

    Abstract: TO ADDRESS THE CHALLENGES OF LOW COMPUTATIONAL EFFICIENCY AND MESH QUALITY DETERIORATION IN DYNAMIC MESH METHODS FOR CONTINUOUS MOVING BOUNDARY PROBLEMS—SUCH AS ABLATION AND FLUID–STRUCTURE INTERACTION—THIS PAPER PROPOSES TWO EFFICIENT AND ROBUST ENHANCED STRATEGIES BASED ON THE RADIAL BASIS FUNCTION (RBF) METHOD. THE FIRST STRATEGY INTEGRATES AN IMPROVED GREEDY ALGORITHM, INCORPORATING MULTI-POINT ADDITION AND A MINIMUM DISTANCE CONSTRAINT, TO ACCELERATE CONTROL POINT SELECTION. IT SIMPLIFIES PARAMETER CONFIGURATION BY FIXING THE INITIAL MESH SCALING FACTOR AND INCORPORATES LIGHT LAPLACIAN SMOOTHING TO CORRECT LOCAL DISTORTIONS. THE SECOND STRATEGY ACHIEVES LOCALIZED LAYER-WISE DISPLACEMENT PROPAGATION BASED ON CELL TOPOLOGY. STARTING FROM THE MOVING BOUNDARY NODES, IT COMPUTES THE DISPLACEMENT OF NEIGHBORING NODES VIA RBF AND PROPAGATES INWARD LAYER BY LAYER. A DISPLACEMENT THRESHOLD IS APPLIED TO TERMINATE ADJUSTMENTS FOR NODES WITH MINIMAL MOTION, AND GLOBAL SMOOTHING IS SUPPLEMENTED TO ENSURE MESH QUALITY. VALIDATION USING A SPHERICAL-HEAD CYLINDER ABLATION CASE DEMONSTRATES THAT THE PROPOSED METHODS SIGNIFICANTLY IMPROVE COMPUTATIONAL EFFICIENCY WHILE MAINTAINING HIGH MESH QUALITY. ADDITIONALLY, THEY ARE SUCCESSFULLY COUPLED WITH A HEAT FLUX–TEMPERATURE–ABLATION SOLVER TO SIMULATE A 400-SECOND ABLATION PROCESS. THE RESULTS INDICATE THAT THE PRESENT APPROACH PROVIDES AN EFFICIENT AND RELIABLE DYNAMIC MESH SOLUTION FOR CONTINUOUS MOVING BOUNDARY PROBLEMS.

     

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