About this Research Topic
At first glance, droplets are common and simple entities, which can easily be produced by numerous natural and industrial processes. They are daily encountered and their industrial usage is extremely wide. For example, droplets may be sprayed to coat a surface, or to cool it down. They may also be ignited, evaporated or chilled to obtain optimal combustion, regular capsules or particles. To do so, it is essential to adjust their size, velocity and trajectory. Combining controlled droplet formation with appropriate deposition and subsequent phase change is the basis of inkjet 3D printing. In contrast, under certain circumstances, for example if the droplets contain infectious or dangerous substances, their formation must be avoided and their capture is necessary. This may be achieved with the help of rightly designed filters.
Despite apparent simplicity and commonness, the full physics of droplets has not yet been unraveled. This is especially true if dynamic and thermodynamic forces come to play. This lack of precise knowledge keeps hindering the rational scale-up and optimization of numerous applications at industrial level. It is the consequence of the complexity of the fluid mechanic and thermodynamic equations, which can most of the time not be solved analytically. The difficulty increases when capillary pressure must be accounted for taking the form of not trivial boundary conditions, and when the simultaneous exchange of mass, momentum and energy leads to the interdependent transport equations. Thanks to the development of numerical methods some light could already be shed on certain systems. Yet, when drops are involved, the computational approach often reaches its limit. It is for example the case when the fluid interface and its topological changes must be tracked, when wetting dynamics is important, or simply when the time- and length-scales to be resolved are small compared to the process scales. Furthermore and despite advances in experimental techniques, such as high-speed imaging, many processes remain unexplored or poorly understood.
This Research Topic aims to give an overview of the recent developments in physics of droplet, including dynamic and thermodynamic aspects. Approaches may be based on theory, experiments, numerical simulations or be a combination of them. Original Research articles focusing on the following sub-topics are especially welcome:
- liquid atomization, droplet formation and applications to spray based processes and inkjet printing
- droplet collisions with other liquid entities such as droplet, jet, film, pool, and applications - for example - to liquid encapsulation
- droplet impacts with solid objects such as smooth/microstructured/porous substrates, particles, fibers,...and applications to coating, cooling, filtration
- droplet condensation, evaporation, solidification and applications - for example - water harvesting/recovery, spray drying, 3D printing
- contributions about microfluidics are welcome in this Research Topic
Despite apparent simplicity and commonness, the full physics of droplets has not yet been unraveled. This is especially true if dynamic and thermodynamic forces come to play. This lack of precise knowledge keeps hindering the rational scale-up and optimization of numerous applications at industrial level. It is the consequence of the complexity of the fluid mechanic and thermodynamic equations, which can most of the time not be solved analytically. The difficulty increases when capillary pressure must be accounted for taking the form of not trivial boundary conditions, and when the simultaneous exchange of mass, momentum and energy leads to the interdependent transport equations. Thanks to the development of numerical methods some light could already be shed on certain systems. Yet, when drops are involved, the computational approach often reaches its limit. It is for example the case when the fluid interface and its topological changes must be tracked, when wetting dynamics is important, or simply when the time- and length-scales to be resolved are small compared to the process scales. Furthermore and despite advances in experimental techniques, such as high-speed imaging, many processes remain unexplored or poorly understood.
This Research Topic aims to give an overview of the recent developments in physics of droplet, including dynamic and thermodynamic aspects. Approaches may be based on theory, experiments, numerical simulations or be a combination of them. Original Research articles focusing on the following sub-topics are especially welcome:
- liquid atomization, droplet formation and applications to spray based processes and inkjet printing
- droplet collisions with other liquid entities such as droplet, jet, film, pool, and applications - for example - to liquid encapsulation
- droplet impacts with solid objects such as smooth/microstructured/porous substrates, particles, fibers,...and applications to coating, cooling, filtration
- droplet condensation, evaporation, solidification and applications - for example - water harvesting/recovery, spray drying, 3D printing
- contributions about microfluidics are welcome in this Research Topic
Keywords: fluid dynamics, drop impacts, phase change, drop collisions, fragmentation, coalescence, encapsulation, splash
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.
