A novel experimental approach for studying the aerodynamics of ice particles is presented. The Trajectory Reconstruction Algorithm implemented through Image anaLysis (TRAIL) produces digital reconstructions of the trajectory and orientation of 3D‐printed analogues of ice particles that fall through a quiescent viscous liquid. Data extracted from this analysis can be used to test fall speed parametrisations and investigate the preferred orientation of analogues with complex irregular geometries. Experiments using thin circular discs are used to validate this approach. Measurements from a case study in which an analogue of an aggregate ice particle is used are also reported. Data extracted from the analysis clearly demonstrate important, but poorly understood, aspects of the aerodynamics of atmospheric ice particles. For example, the orientation that the analogue adopts in free fall is shown to depend not only on the geometric shape of the particle, but also on the Reynolds number at which it falls. In addition, measurements of the drag coefficient indicate that the accuracy of fall speed parametrisations reduces at high Reynolds number due to the onset of unsteady motions.

中文翻译：

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TRAIL：研究冰粒空气动力学的新方法

提出了一种新颖的实验方法，用于研究冰粒的空气动力学。通过图像分析（TRAIL）实施的轨迹重建算法可对3D打印的冰粒通过类似静态液体落下的类似物的轨迹和方向进行数字重建。从此分析中提取的数据可用于测试跌落速度参数设置，并研究具有复杂不规则几何形状的类似物的首选方向。使用薄圆盘的实验被用来验证这种方法。还报道了案例研究中使用聚集冰粒类似物的测量结果。从分析中提取的数据清楚地表明了大气冰粒空气动力学的重要但知之甚少。例如，研究表明，类似物在自由下落中所采用的取向不仅取决于粒子的几何形状，还取决于其下落时的雷诺数。此外，阻力系数的测量结果表明，由于不稳定运动的开始，在高雷诺数下，下降速度参数设置的精度会降低。