Development of an immersed boundary method for multiphase flow

• Applicant: Dr.-Ing. Daniel Hartmann
• Subject Area: Fluid Mechanics
• Term: from 2010 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 187434388

The impact of liquid drops on dry surfaces or liquid films is relevant for many technological processes. For example, drop impact is known to cause structural damage of steam turbine blades which is referred to as erosion. The dynamics of drop impact exhibits a variety of regimes such as crown splash, where a thin liquid sheet jets immediately after the drop impact and becomes unstable to form ligaments of liquid which finally break up into small secondary droplets, or the deposition of the impacting drop without the formation of small droplets. Generally, the numerical simulation of such multiphase flows is very demanding since it requires an accurate description of the evolving interface between the phases, an accurate computation of the surface tension acting at the phase boundary, and the robust treatment of the typically large density and viscosity jumps at the interface.The motivation of the proposed research is to physically understand the relationship between the momentum transfer from the drops to the surface and the impact angle. To this end, the central objective of the proposed research is to develop a unified accurate and efficient numerical method to simulate flows with moving boundaries and multiphase flows on the basis of the immersed boundary method. In this method, the presence of the solid boundaries is accounted for by forcing terms which are added to the Navier-Stokes equations governing the flow. In a similar way, the developed method should account for the phase boundaries in multiphase flows. Hence, computational grids which do not conform to the shape of the boundaries can be used, making the simulation of flows with complex interfaces such as the evolving phase boundary accessible. The developed numerical method should be used to study in detail the dynamics of liquid drop impacts on dry surfaces and liquid films varying the impact angle and droplet properties such as its size and the impact velocity.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Tim Colonius, Ph.D.