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Droplet impinging on liquid film is significant for many industrial processes. In this work, the normal impact of a single droplet on different thickness of concave curved liquid films is simulated. Coupled level set and volume of fluid method is used to capture the dynamics of drop impact and crown spreading. The variation of pressure field of droplets impacting the curved liquid film is investigated. The effect of film thickness and wall curvature on the water crown behavior is studied. With the curvature ratio increasing, the elevation angle of the velocity vector at crown rim increases, and the velocity gradient inside the crown decreases. The increase in curvature ratio also makes the crown sheet incline inward and suppresses the splash. The thickness of liquid film will lead to discrepancies in crown behaviors. The thin film makes the spreading speed of crown rim faster, and the crown top will shrink and splash. With the thickening of the liquid film, the influence of the thickness on the shape and size of the crown weakens. The separation of crown influenced by thin film is also analyzed.
Chen et al. (2024) studied this question.