Inertio-capillary rebound of a droplet impacting a fluid bath
Inertio-capillary rebound of a droplet impacting a fluid bath
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DOI：
10.1017/jfm.2023.88
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发表时间：
2022-09
影响因子：
3.7
通讯作者：
L. Alventosa;R. Cimpeanu;D. Harris
中科院分区：
文献类型：
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作者：
L. Alventosa;R. Cimpeanu;D. Harris
摘要从实验和理论两方面研究了液滴撞击深液浴时的回弹现象。毫米级液滴是由压电式按需液滴发生器产生的，通常会撞击同一液体的浴缸。液滴轨迹和其他回弹指标的测量结果直接与线性准势模型的预测结果进行了比较，并与非定常Navier-Stokes方程的完全解析直接数值模拟结果进行了比较。除了液滴轨迹外，这两个模型还解决了随时间变化的浴槽和液滴形状。在准势模型中，采用正交函数分解方法对液滴和槽形进行分解，得到两组耦合阻尼线性谐振子方程，并用隐式数值方法求解。液滴的欠阻尼动力学通过单点运动学匹配条件直接耦合到槽的响应，我们证明了这是我们感兴趣的参数范围内的有效模型。从惯性-毛细极限出发，重力和粘性的影响都可以忽略不计，重力或粘性的增加导致恢复系数的降低和接触时间的增加。惯性-毛细极限定义了液滴-浴碰撞可能恢复系数的上界，仅取决于韦伯数。准势模型能够使恢复系数的历史实验测量合理化，首先由Jayaratne和Mason （Proc. R. Soc）提出。Lond。A，卷280，第1383期，1964年，第545-565页)。
Abstract The rebound of droplets impacting a deep fluid bath is studied both experimentally and theoretically. Millimetric drops are generated using a piezoelectric droplet-on-demand generator and normally impact a bath of the same fluid. Measurements of the droplet trajectory and other rebound metrics are compared directly with the predictions of a linear quasipotential model, as well as fully resolved direct numerical simulations of the unsteady Navier–Stokes equations. Both models resolve the time-dependent bath and droplet shapes in addition to the droplet trajectory. In the quasipotential model, the droplet and bath shape are decomposed using orthogonal function decompositions leading to two sets of coupled damped linear harmonic oscillator equations solved using an implicit numerical method. The underdamped dynamics of the drop are directly coupled to the response of the bath through a single-point kinematic match condition which we demonstrate to be an effective and efficient model in our parameter regime of interest. Starting from the inertio-capillary limit in which both gravitational and viscous effects are negligible, increases in gravity or viscosity lead to a decrease in the coefficient of restitution and an increase in the contact time. The inertio-capillary limit defines an upper bound on the possible coefficient of restitution for droplet–bath impact, depending only on the Weber number. The quasipotential model is able to rationalize historical experimental measurements for the coefficient of restitution, first presented by Jayaratne & Mason (Proc. R. Soc. Lond. A, vol. 280, issue 1383, 1964, pp. 545–565).