Numerical simulation of a water droplet splash: Effects of density interpolation schemes

• Published in: Mechanics research communications 2018-06, Vol.90, p.18-25
• Main Authors: Fontes, Douglas Hector, Duarte, Carlos Antonio Ribeiro, de Souza, Francisco José
• Format: Article
• Language: English
• Subjects: Droplet; Splash; Unstructured mesh; VoF schemes
• ISSN: 0093-6413; 1873-3972
• DOI: 10.1016/j.mechrescom.2018.04.003

•Numerical simulations of water droplet splash were performed.•VoF/CICSAM method were able to capture the main features of the splash•Different density interpolation schemes were compared.•The density interpolation scheme based on CICSAM terms was the best.•Numerical results fitted well with experimental data. [Display omitted] Flows of two immiscible fluids are widely found in many industrial and natural applications, such as: refrigeration, combustion, irrigation, rain and cavitation. The comprehension/prediction of these kind of flows, simply termed henceforward as two-phase flows, is very important. In this work, water droplet splash cases were studied numerically. This problem is a very interesting two-phase flow, since it occurs in film formation problems, and reliable experimental measures are easily obtained (which is rare in two-phase flow problems), being found in the literature. The VoF model was employed to simulate the impact of a water droplet on a water pool. Although the geometrical schemes, such as PLIC (Piecewise-Linear Interface Calculation) has been demonstrated to yield good results for this problem, it is a rather complex, computationally expensive method, especially when applied to unstructured meshes in many practical problems. Instead, the CICSAM scheme (Compressive Interface Capturing Scheme for Arbitrary Meshes) was used in this work because of its low computational cost and accuracy. The effect of four different schemes for the density interpolation was investigated: central difference, first-order upwind, the second-order and volume fraction weighted. All simulations were compared with experimental data for both the crater depth and ascending jet resulting from the droplet impact. In general, good agreement for the crater depth was found for all the density interpolation schemes, although the volume fraction weighted scheme produced the best results for the ascending jet height. Thus, the VoF/CICSAM method, mainly using the volume fraction weighted scheme for density, proved to be computationally cheaper and reliable to analyze the water droplet splash cases. The methodology presented in this work can be extended to other two-phase flows applications.