A Modified Weber Number Capturing the Bouncing–Wetting Transition of Droplet Impact on Rough Surfaces

Abstract

coating, [1] inkjet printing, [2] deposition of pesticides, [3] and anti-icing applications. [4] Since the pioneering work of Worthington on rapid droplet impact, [5] the underlying dynamics of the interplay among liquid droplet, ambient gas, and substrate have been investigated by many researchers. [6][7][8] Experimental investigations of droplet impact on solid substrate revealed six identical modes, including deposition, partial bouncing, complete bouncing, receding breakup, prompt splash, and corona splash. [9] The outcome of droplet collision depends on various factors, such as droplet properties, [10] surface conditions, [11,12] ambient pressure, [13] and impacting angle and velocity. [14] Dimensionless numbers are used to characterize the droplet impact dynamics,

Enhancing the Output of Liquid–Solid Triboelectric Nanogenerators through Surface Roughness Optimization

“…Relevant studies suggest that the actual wetted area between the droplet and substrate plays a significant role in determining the droplet impact outcome on heterogeneous rough surfaces, with a higher surface area ratio promoting the impact outcome transition from bouncing to wetting. 41 Second, the surface charge density is proportional to the Weber number from the formula ρ Q ∝ We 0.74 . 42 The Weber number We = ρDν 2 /γ, where D, ν, and γ represent the diameter, impact velocity, and surface tension of the drop, respectively.…”

“…We investigated the influence of different liquid parameters on the output of LS-TENG. Relevant studies suggest that the actual wetted area between the droplet and substrate plays a significant role in determining the droplet impact outcome on heterogeneous rough surfaces, with a higher surface area ratio promoting the impact outcome transition from bouncing to wetting . Second, the surface charge density is proportional to the Weber number from the formula ρ Q ∝ We 0.74 .…”