Abstract Long time simulations of the dispersion of prolate spheroids in a turbulent channel are performed to study the effect of the averaging procedure on particle statistics. The turbulent flow at R e τ = 180 is directly simulated (DNS) and 300 000 ellipsoids, modelled as point-particles are tracked to produce statistics. After a long time, an initially uniform particle distribution reaches a steady state in which almost all particles are segregated in the viscous sublayer. The final state of the distribution depends on the particle shape and relaxation time. Statistics of the particle velocity (translational and angular), orientation and concentration are then computed, using different averaging durations, before and after the particle distribution reaches the equilibrium. The steadiness of the distribution may have a significant effect on the statistics, especially for those strongly tied to the particle wall-normal motion. A non negligible influence of the averaging duration is also noticed for some statistics of high inertia particles.

中文翻译：

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湍流通道流中长球体动力学的长时间统计。

摘要 对长球体在湍流通道中的分散进行了长时间的模拟，以研究平均过程对粒子统计的影响。Re τ = 180 处的湍流被直接模拟 (DNS) 和 300 000 个椭球，模拟为点粒子被跟踪以产生统计数据。很长一段时间后，最初均匀的颗粒分布达到稳定状态，其中几乎所有的颗粒都在粘性亚层中分离。分布的最终状态取决于粒子形状和弛豫时间。然后，在粒子分布达到平衡之前和之后，使用不同的平均持续时间计算粒子速度（平移和角）、方向和浓度的统计数据。分布的稳定性可能对统计有显着影响，特别是对于那些与粒子壁法向运动密切相关的统计。对于高惯性粒子的一些统计数据，也注意到平均持续时间的不可忽略的影响。