New publication, published in the scientific journal "Atomization and Sprays". The work has been developed in the context of the SFB 1313 research projects A02 and D01.
"Quantitative Analysis of the Asymmetry of Inner Wall Film Flow in Oblique Droplet Impacts"
Authors
Abstract
During an oblique droplet impact on a thin wall film, an asymmetric crown forms, but a quantitative description of this asymmetry is still missing. Crown ejection, propagation, and splashing are driven by the inner wall film, making its asymmetry crucial in understanding the overall asymmetry. In this study, the asymmetry of the inner film flow is analyzed with Direct Numerical Simulations. A reference case with an impact angle of α = 70° is examined in detail, followed by a variation of impact angle, Weber number, Ohnesorge number, film thickness, and wall boundary conditions. The velocity field and the liquid’s mass and momentum distribution in azimuthal sections are extracted to characterize asymmetries. Lower impact angles increase asymmetry in amplitude and distribution function. A fluid tracking analysis over the redirection phase provides further insight into the origin of asymmetry. A one-parameter geometric model, based on an azimuthal cut of a sphere, accurately reproduces the momentum distribution for all investigated conditions, with the parameter depending solely on the impact angle. This study comprehensively explains the asymmetry of the inner wall film flow and provides a foundation for the overall asymmetry of oblique impacts.