Particle deposition dynamics in a fully developed turbulent channel flow at a friction Reynolds number of for two Stokes numbers ( and 10) are investigated using the point particle-direct numerical simulation (PP-DNS) method, considering dilute system and thus, one-way coupling. In particular, the interplay between particle size, particle property (density) and deposition at the same Stokes number has been investigated. It turns out that the dimensionless particle relaxation time (the Stokes number) alone does not provide enough information to capture the deposition dynamics, and particle size (diameter) and density need to be considered to obtain a more comprehensive understanding of deposition process. Furthermore, we demonstrate that gravity significantly alter the deposition patterns of particles with different size and density differently, even if the Stokes number does not change, and therefore the results from zero gravity cannot be extrapolated to non-zero gravity settings, even for small particles. Finally, our results suggest that wall-normal particle velocity variance at the wall plays an integral role in the deposition process, as it approaches a finite value (significantly larger than particle mean velocity) at the wall.

中文翻译：

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湍流壁界流中颗粒特性对小颗粒沉积影响的计算研究

使用点粒子直接数值模拟 (PP-DNS) 方法研究了完全发展的湍流通道流中摩擦雷诺数为两个斯托克斯数（和 10）时的颗粒沉积动力学，考虑了稀释系统，因此单向耦合。特别是，研究了相同斯托克斯数下颗粒尺寸、颗粒特性（密度）和沉积之间的相互作用。事实证明，仅无量纲颗粒弛豫时间（斯托克斯数）并不能提供足够的信息来捕获沉积动力学，需要考虑颗粒尺寸（直径）和密度，以获得对沉积过程的更全面的了解。此外，我们证明，即使斯托克斯数没有改变，重力也会显着改变不同尺寸和密度的颗粒的沉积模式，因此零重力的结果不能外推到非零重力设置，即使对于小颗粒也是如此。最后，我们的结果表明，壁处的壁法向粒子速度方差在沉积过程中起着不可或缺的作用，因为它在壁处接近有限值（显着大于粒子平均速度）。