The Impact of Drops on Walls and Films

A study of droplet impact on static films using the BB-LIF technique

“…This correlates with the Model (τ=2) Model (τ=3) Model (τ=5) result that thicker films need a higher velocity of impact to generate crown breaking. This could help explain the height of film dependence noted by (Cossali et al 1997;Tropea and Marengo 1999). It is interesting that it is only the cases where the droplet liquid expands to the cavity width that show crown breaking in our results.…”

“…(Cossali et al 1997;Tropea and Marengo 1999;Okawa et al 2006). This parameter is used in this work in analysing the impact evolutions and is defined in Table 1.…”

CFD analysis of the impact of physical parameters on evaporative cooling by a mist spray system

“…The presence of a liquid on the surface changes the boundary condition and the impact leads to a liquideliquid interaction. In this case, the impact characteristics depend on the surface roughness but also the film thickness compared with the droplet size [50]. However, the effect of the film thickness is not taken into account.…”

Generalized analysis of the deposition/splashing limit for one- and two-component droplet impacts upon thin films

“…They are of particular interest since they lead to the ejection of secondary droplets, the so-called splashing.The investigations concerning the droplet impact on wetted walls show that for a given Reynolds number (Re), Ohnesorge number (Oh) and dimensionsless wall film thickness (δ, film thickness h over droplet diameter D), the outcome of one-component droplet impact can be determined. Roughness of the wall can be neglected in the case of 0.1 ≤ δ ≤ 1 [9], when it is completely embedded in the liquid wall film. However, drop-film interactions are affected by the use of different fluids for the droplet and the liquid film.…”

“…For this purpose, different existing correlations will be considered. Many studies were performed for the deposition/splashing limit of one-component interaction such as Yarin and Weiss [7], Cossali et al [2], Coghe et al [8], Marengo and Tropea [9], Wang and Chen [11], Rioboo et al [10], Vander Wal et al [1] just to name a few. The latter [1] encompasses a study on one-component interaction of twelve different fluids (ranging from alkanes to alcohols and including mixtures of glycerol-water).…”