松弛迭代粒子追踪测速法独立性改进

为了提高提取瞬态流场结构的便捷性,对松弛迭代粒子追踪测速法(RM-PTV)的独立性进行了改进.引入Delaunay三角剖分(DT)法代替固定阈值法来选取与目标粒子保持相似运动的参选粒子并对典型自定义流场进行了匹配计算,同时引入邻域窗口分析法对改进前后的流场在匹配结果中突兀矢量分布的数量和大小进行了比较.计算结果表明:DT方法可以有效选取目标的参选粒子,改进方法可以较好地保持抗噪音和识别粒子无匹配的能力,省去固定阈值的选取,减小对具体流场的依赖性;当噪音和粒子无匹配存在时,改进前后的流场在匹配结果中突兀矢量分布的数量和大小基本相同.最后,通过实验证明了改进方法在大气边界层内提取沙粒跃移运动轨迹上是有效的.

Independence Improvement for Relaxation Method Based Particle Tracking Velocimetry

The independence of the relaxation method based particle tracking velocimetry(RM-PTV) was improved to obtain the instantaneous flow structure more conveniently.Delaunay triangulation(DT) was employed to determine reference particles which preserve similar motion with target particles and simulation calculation was done for the typical self-defined flow fields.The neighborhood window method was applied to analyze the fake vectors’ distribution and magnitude.The results show that DT can effectively determine the reference particles and the improved algorithm reserves the advantages of against noise and calculating "particles having no matched candidate";fake vectors’ distribution and magnitude appear to be quite similar in the two cases when noise and particles having no matched candidate exist.The improved RM-PTV was employed to track trajectories of saltating sand in an atmospheric boundary layer and the results can meet the requirement.It seems that the independence can be improved and the original advantages can be reserved by adopting DT in RM-PTV.