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2013
Impact Factor

Stefan Llewellyn Smith

9500 Gilman Drive, La Jolla CA 92093-0411, USA
Department of Mechanical and Aerospace Engineering, University of California

Publications:

Llewellyn Smith S. G., Chang C., Chu T., Blyth M., Hattori Y., Salman H.
Generalized Contour Dynamics: A Review
2018, vol. 23, no. 5, pp.  507-518
Abstract
Contour dynamics is a computational technique to solve for the motion of vortices in incompressible inviscid flow. It is a Lagrangian technique in which the motion of contours is followed, and the velocity field moving the contours can be computed as integrals along the contours. Its best-known examples are in two dimensions, for which the vorticity between contours is taken to be constant and the vortices are vortex patches, and in axisymmetric flow for which the vorticity varies linearly with distance from the axis of symmetry. This review discusses generalizations that incorporate additional physics, in particular, buoyancy effects and magnetic fields, that take specific forms inside the vortices and preserve the contour dynamics structure. The extra physics can lead to time-dependent vortex sheets on the boundaries, whose evolution must be computed as part of the problem. The non-Boussinesq case, in which density differences can be important, leads to a coupled system for the evolution of both mean interfacial velocity and vortex sheet strength. Helical geometry is also discussed, in which two quantities are materially conserved and whose evolution governs the flow.
Keywords: vortex dynamics, contour dynamics, vortex patch, vortex sheet, helical geometry
Citation: Llewellyn Smith S. G., Chang C., Chu T., Blyth M., Hattori Y., Salman H.,  Generalized Contour Dynamics: A Review, Regular and Chaotic Dynamics, 2018, vol. 23, no. 5, pp. 507-518
DOI:10.1134/S1560354718050027
Llewellyn Smith S. G., Nagem R. J.
Vortex Pairs and Dipoles
2013, vol. 18, no. 1-2, pp.  194-201
Abstract
Point vortices have been extensively studied in vortex dynamics. The generalization to higher singularities, starting with vortex dipoles, is not so well understood.We obtain a family of equations of motion for inviscid vortex dipoles and discuss limitations of the concept.We then investigate viscous vortex dipoles, using two different formulations to obtain their propagation velocity. We also derive an integro-differential for the motion of a viscous vortex dipole parallel to a straight boundary.
Keywords: vortex pair, vortex dipole
Citation: Llewellyn Smith S. G., Nagem R. J.,  Vortex Pairs and Dipoles, Regular and Chaotic Dynamics, 2013, vol. 18, no. 1-2, pp. 194-201
DOI:10.1134/S1560354713010140

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