Using computational steering to explore the parameter space of stability in a suspension

We simulate a suspension of model colloidal particles interacting via DLVO (Derjaguin, Landau, Vervey, Overbeek) potentials. The interaction potentials can be related to experimental conditions, defined by the pH-value, the salt concentration and the volume fraction of solid particles suspended in the acqueous solvent. Depending on these parameters, the system shows different structural properties, including cluster formation, a glass-like repulsive structure, or a stable suspension. To explore the parameter space many simulations are required. In order to reduce the computational effort and data storage requirements, we developed a steering approach to control a running simulation and to detect interesting transitions from one region in the configuration space to another. In this article we describe the implementation of the steering in the simulation program and illustrate its applicability by several example cases

Liquid metal flows driven by rotating and traveling magnetic fields

Alternating magnetic fields provide a comfortable means for non-intrusive flow control in conductive fluids. However, despite a long history of applications in metallurgy and crystal growth, detailed investigation of the practically important transitional and turbulent flow regimes has become possible only in the last dozen years. The present review gives an overview of this topic with focus on recent experimental and numerical studies of the flow driven by rotating and traveling magnetic fields. We discuss the three-dimensional, instantaneous flow structure as well as the resulting average transport properties for a broad range of parameters, including the superposition of both field types. In addition to the ideal case, the effect of a misalignment of the field with respect to the container axis will be considered, too