Drop Transmission After the Impact on Woven fabrics

Droplet and drop penetration through a woven fabric surface depends on the surface's geometrical properties and wetting properties. In addition, the inertial effect could break the drop and allow the transmission of many smaller droplets. This mechanism is present in cloth face masks and could affect their outward protection effectiveness for coughing, sneezing, or speaking. A numerical method is presented for simulating the impact of drops on woven fabrics. Adaptive mesh refinement (AMR) and the moment-of-fluid method are employed to capture the complex interface separating the drop from the surrounding gas and woven fabric. The roles of pore size, hydrophobicity of the materials and impact momentum of the drop are investigated. The results are further used to find a ``drop-fabric'' relation based on the Weber number for different fabric woven structures to represent transmitted droplets' size and velocity distributions. An immediate application of the presented research is the application of numerical computations to study the effectiveness of different fabrics in preventing the spread of respiratory infections such COVID-19.