Adrian Lange

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The Kelvin force in a layer of magnetic fluid subjected to a homogeneous magnetic field and local heating is studied. The study is motivated by the question about the corresponding Kelvin force density [M. Liu, Phys. Rev. Lett. 84, 2762 (2000)]. It is shown that the usual and the newly proposed formulation of the Kelvin force are entirely equivalent. It is(More)
Navigational queries are among the most natural query patterns for RDF data, but yet most existing RDF query languages fail to cover all the varieties inherent to its triple-based model, including SPARQL 1.1 and its derivatives. As a consequence, the development of more expressive RDF languages is of general interest. With TriAL* [14], there exists an(More)
  • Adrian Lange
  • Physical review. E, Statistical, nonlinear, and…
  • 2004
The ferrofluid dynamics theory is applied to thermodiffusive problems in magnetic fluids in the presence of magnetic fields. The analytical form for the magnetic part of the chemical potential and the most general expression of the mass flux are given. By applying these results to experiments, global Soret coefficients in agreement with measurements are(More)
We investigate the growth of a pattern of liquid crests emerging in a layer of magnetic liquid when subjected to a magnetic field oriented normally to the fluid surface. After a steplike increase of the magnetic field, the temporal evolution of the pattern amplitude is measured by means of a Hall-sensor array. The extracted growth rate is compared with(More)
Transient patterns of the Rosensweig instability are accessed with a pulse sequence. The critical scaling behavior of the oscillation frequency and of the propagation velocity of these patterns is experimentally investigated by switching the magnetic induction to subcritical values. The experimental findings are in good agreement with the linear theory, if(More)
A linear stability analysis of the free surface of a horizontally unbounded ferrofluid layer of arbitrary depth subjected to vertical vibrations and a horizontal magnetic field is performed. A nonmonotonic dependence of the stability threshold on the magnetic field is found at high frequencies of the vibrations. The reasons for the decrease of the critical(More)
To describe the dynamics of a single peak of the Rosensweig instability a model is proposed which approximates the peak by a half-ellipsoid atop a layer of magnetic fluid. The resulting nonlinear equation for the height of the peak leads to the correct subcritical character of the bifurcation for static induction. For a time-dependent induction the effects(More)
The decay of metastable patterns in the form of magnetic liquid ridges is studied in the frame of a linear stability analysis where the ridges are the most unstable linear pattern of the Rosensweig instability. The analysis of the corresponding dispersion relation reveals that different sets of solutions exist. Two of them are associated with an oscillatory(More)
An analysis of thermomagnetic convection in a thin horizontal layer of magnetic fluid constrained horizontally by impermeable layers and subjected to a spatially and symmetrically modulated magnetic field is presented. The magnetic field as well as the temperature gradient are oriented vertically. For any nonzero magnetic field the base state is a(More)