Impact force of a low speed water droplet colliding on a solid surface

Abstract

The impact forces of the low-speed water droplet colliding on a light and tiny aluminum plate were measured by using a highly sensitive piezoelectric force transducer. The one-degree freedom vibration model was employed to analyze the oscillation of the measured force signals, and the plate vibration was confirmed as the cause through elaborately designed experiments. The force data were obtained by using the low-pass Finite Impulse Response filter and was verified to be reliable. The effects of impact velocity and diameter of droplets on the impact force evolutions and peak forces were investigated. The results revealed that the impact process of a liquid droplet is quite different from that of a solid ball in the frequency spectrum and in the power function of the peak force. The droplet impact is closer to a plastic impact, while the other behaves more nearly an elastic impact. The influence of droplet size on erosion is dependent on the impact time duration, which increases with droplet diameter. On the other hand, the impact pressure is the main cause of the material erosion when impact velocity is taken as the influence factor.

Dynamics of drop impact on solid surfaces: evolution of impact force and self-similar spreading

“…Through this study, we experimentally verify the existence of an upward propagating self-similar structure during the initial impact of liquid drops at high Re (Eggers et al 2010;Philippi et al 2016). Our quantitative analysis on the temporal variation of impact forces also predicts the maximum impact force and the associated peak time as a function of Re, which have been extensively studied in experiments (Nearing et al 1986;Grinspan & Gnanamoorthy 2010;Li et al 2014;Soto et al 2014;Zhang et al 2017). Second, we generalise the self-similar solution of drop spreading proposed by Eggers and co-workers (Eggers et al 2010) and find an exact parameter-free closed-form self-similar solution for inertia-driven drop spreading following the initial impact.…”

“…Although the maximum impact force of liquid drops has been measured in previous studies, the presence of strong resonant ringing and the abnormal slow decay of impact forces have limited the application of piezoelectric force sensors in resolving the temporal evolution of impact forces (Nearing et al 1986;Grinspan & Gnanamoorthy 2010;Li et al 2014;Soto et al 2014;Zhang et al 2017). Here, we solved these problems by targeting the impinging drops slightly off the centre of the force sensor, which significantly reduced resonant ringing.…”

“…Nevertheless, compared with the large number of studies on the morphology of impacting liquid drops, comparatively fewer experiments have been conducted to investigate the impact force of liquid drops. Most of the existing works have focused on the maximum impact force of liquid drops (Nearing et al 1986;Grinspan & Gnanamoorthy 2010;Li et al 2014;Soto et al 2014;Zhang et al 2017). The temporal evolution of impact forces during impacts remains largely unexplored.…”

Effect of Raindrop Temperatures on Soil Runoff and Erosion in Dry and Wet Soils. A Laboratory Experiment

“…According to the Eötvös rule (Palit, 1956), surface tension of raindrops decreases linearly with increasing temperature, and the droplet impact process is plastic rather than elastic (Li, Zhang, Guo, & Lv, 2014). As the Weber number decreases, the deformation of a drop subjected to impact also decreases (Richard, Clanet, & Quéré, 2002), so that more energy is applied to drop deformation rather than to soil deformation.…”

Impact of a Square Liquid Body on a Rigid Plate

“…Rein (1993) has described and reviewed the phenomena of liquid drop impact, including bouncing, spreading and splashing on solid surfaces [3]. Li, Zhang, Guo and Lv (2014) measured the impact forces of the low-speed water droplet colliding on a light and tiny aluminum plate using a highly sensitive piezoelectric force transducer [4].…”