Christian Gollwitzer

List of publications

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  The normal field instability under side-wall effects: comparison of experiments and computations

  Christian Gollwitzer, Antonis N Spyropoulos, Athanasios G Papathanasiou, Andreas G Boudouvis, Reinhard Richter

  A single spike of ferrofluid in a small cylindrical pool is both computed from first principles and observed by two independent experimental techniques.

  New J. Phys. 11, 053016 (2009) ► New J. Phys.

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  Surface Instabilities and Magnetic Soft Matter

  Christian Gollwitzer, Marina Krekhova, Guenter Lattermann, Ingo Rehberg, Reinhard Richter

  Thermoreversible ferrogels, when exposed to a vertical magnetic field, exhibit a spontaneous formation of peaks, which can be controlled by temperature.

  Soft Matter 5, 2093 (2009) ► arXiv ► movie

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  Measuring the deformation of a ferrogel sphere in a homogeneous magnetic field

  Christian Gollwitzer, Alexander Turanov, Marina Krekhova, Günter Lattermann, Ingo Rehberg, Reinhard Richter

  A sphere of a ferrogel, when exposed to a homogeneous magnetic field, gets elongated along the field lines and vibrates after an initial rapid excitation. This is described by a damped harmonic oscillator model, and Poisson's ratio of the gel is deduced.

  J. Chem. Phys. 128, 164709 (2008) ► arXiv
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  Response of a ferrofluid to traveling-stripe forcing

  Achim Beetz, Christian Gollwitzer, Reinhard Richter, Ingo Rehberg

  Plane waves propagating on the surface of a ferrofluid are excited by a spatially and temporally modulated magnetic field exhibiting a resonance phenomenon similar to that of a forced harmonic oscillator.

  J. Phys.: Condens. Matter 20, 204109 (2008) ► arXiv

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  Via Hexagons to Squares in Ferrofluids: Experiments on Hysteretic Surface Transformations under Variation of the Normal Magnetic Field

  Christian Gollwitzer, Ingo Rehberg, Reinhard Richter

  For the hexagon–square transition of the pattern of spikes on the surface of a magnetic liquid, we tailor a set of order parameters like peak-to-peak distance, circularity, angular correlation function and pattern specific amplitudes from Fourier space.

  J. Phys.: Condens. Matter 18, S2643 (2006) ► arXiv

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  The Surface Topography of a Magnetic Fluid — a Quantitative Comparison between Experiment and Numerical Simulation

  Christian Gollwitzer, Gunar Matthies, Reinhard Richter, Ingo Rehberg, Lutz Tobiska

  The normal field instability in magnetic liquids is investigated experimentally by means of a radioscopic technique which allows a precise measurement of the surface topography, and compared to results obtained by numerical simulations via the finite element method.

  J. Fluid. Mech. 571, 455 (2007) ► arXiv