Monika Nitsche

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Regularized point-vortex simulations are presented for vortex sheet motion in planar and axisymmetric flow. The sheet forms a vortex pair in the planar case and a vortex ring in the axisymmetric case. Initially the sheet rolls up into a smooth spiral, but irregular small-scale features develop later in time: gaps and folds appear in the spiral core and a(More)
This paper concerns the accurate evaluation of the principal value integral governing axisymmetric vortex sheet motion. Previous quadrature rules for this integral lose accuracy near the axis of symmetry. An approximation by de Bernadinis and Moore (dBM) that converges pointwise at the rate of O(h3) has maximal errors near the axis that are O(h). As a(More)
Point vortex and vortex blob computations are used to investigate the evolution of the planar and the axisymmetric vortex sheet which initially induce ow past a cylinder and past a sphere respectively. In both cases the sheet develops a singularity at two points in the symmetry plane at a nite time. It rolls up at these points forming a vortex pair in the(More)
This article reviews some recent simulations of vortex sheet roll-up using the vortex blob method. In planar and axisymmetric flow, the roll-up is initially smooth but irregular small-scale features develop later in time due to the onset of chaos. A numerically generated Poincaré section shows that the vortex sheet flow resembles a chaotic Hamiltonian(More)
M. NITSCHE, P. D. WEIDMAN , R. GR IMSHAW , M. GHRIST 4 AND B. FORNBERG Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM 87131 Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309-0427 3 Department of Mathematical Sciences, Loughborough University, Loughborough, LE11 3TU 4 Department of(More)
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