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DY: Fachverband Dynamik und Statistische Physik
DY 27: Poster: Nonlinear Dynamics, Pattern Formation, Granular Matter
DY 27.12: Poster
Mittwoch, 19. März 2025, 15:00–18:00, P4
Force enhancement in-between suszeptible dipolar hard spheres - measurement vs computation — Andree Smolla1, Alexandros G. Sourais2, Sofia S. Kantorovich3, Andreas Boudouvis2, and •Reinhard Richter1 — 1Experimentalphysik 5, Universität Bayreuth, 95447 Bayreuth, Germany — 2School of Chemical Engineering, National Technical University of Athens, Zografu Campus, 15780 Athens, Greece — 3Computational Physics, University of Vienna, 1090 Vienna, Austria
We measure the force acting in-between two magnetized steel spheres used previously in ferrogranular model experiments [1]. When reducing the mutual distance r of the spheres the force r exceeds considerably the scaling ∼ r−4 known from dipolar hard spheres (DHS). To elucidate this deviation we measure the magnetization curves M(H) of both steel spheres by means of a vibrating sample magnetometer. Their magnetization curves show a remanent magnetization plus a contribution which depends on an outer magnetic field, i.e. we have suszeptible dipolar hard spheres (SDHS). Taking into account M(H) we solve the governing equations with the finite element method using FEniCS and COMSOL [2], showing a peak of the magnetization in the contact zone. The estimated force captures the enhanced force measured before.
[1] M. Biersack, A. Lakkis, R. Richter, O. Bilous, P. A. Sánchez, S. S. Kantorovich Phys. Rev. E, 108 (2023) 054905.
[2] Alexandros G. Sourais, Solution of magnetostatics problems with the Finite Element method using FEniCS computational platform, Master Thesis, National Technical University of Athens (2021).
Keywords: ferrogranulate; suszeptible dipolar hard spheres; force enhancement; finite element method; FEniCS