Discrete Elements and Molecular Dynamics
A Novel Design Approach for Safety at Ship Collision
M.Sc. Mohsin Ali Chaudry
Numerical Simulation and Experimental Validation of Biofilm Growth
P. Wriggers , M. Stiesch
Biofilms are bacterial colonies growing on solid-fluid interfaces, wherever enough dissolved nutrients are available. Their formation is a complex process in the sense that several Physical phenomena (Reaction-Diffusion-Advection, Sedimentation, Erosion, Fluid-Solid-Interaction) are coupled and consequently different time-scales are involved. In this project, the focus is on the biofilm formation in a flow chamber which resembles the mouth cavity in the vicinity of dental implants. The goal is to develop a computational tool capable of simulating the biofilm growth. Numerical solution of the Navier–Stokes equation in domains with complex boundaries that dynamically change as a result of biological diffusion-reaction, detachment and sedimentation in biofilm growth presents a very serious challenge to grid-based methods. In this project, a fully Lagrangian particle approach(mesh-less method) based on smoothed particle hydrodynamics (SPH) is developed.
Experimental and Numerical investigation of collision of particle-filled double hull vessel
P. Wriggers, C. Weißenfels
A novel design approach for safety of double hull vessel is presently being investigated, which involves usage of granular materials between the hull of ship. This strategy provides a medium between the hull which can absorb impact energy and transfer the load to the inner hull. Therefore, impact energy is shared between two hulls, in contrast to localized impact on outer hull only.
Non-convex particle shape and parallelization
DFG (Project: IRTG 1627)
Many materials found in nature or technical processes have a granulated structure. Examples are sand and ores, fruits and grain, (dry) pharmaceutical and chemical products. Compared to other materials, granular materials are difficult to handle: Different particle shapes result in different material behaviour. To have a simulation with realistic particle properties, more complex and more realistic particle shapes are needed. This means, in addition to the often used purely convex particles (spheres and ellipsoids), a description for more complex and non-convex shaped particles is essential. The higher computational costs can be handled by a parallelization.
Discrete Element Method
This project is concerned with the development of a discrete element method (DEM) code for the simulation of large particle systems in 3-D, where also complex moving boundary geometries can be taken into account. The DEM is a well established numerical method to simulate systems consisting of granular matter. Granular mixing, tumbling mills, transport of particles via conveyor belts or screw conveyors are just some examples of important particulate processes in industry sectors like mining, pharmaceutical and food industries. For such systems, the optimization of the design variables as well as the appropriate choice of the operating parameters is still a difficult and a challenging task.