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Fluid Dynamics Seminar

Monday, February 19, 2007, 4:15 PM
Cullimore Lecture Hall, Room 611
New Jersey Institute of Technology

Analysis and computations for viscoelastic fluids

Becca Thomases

Courant, New York University

Abstract

Viscoelastic flow modelled by the Oldroyd-B equations will be discussed from an analytical and numerical perspective. First I will present a local energy decay theorem which applies to a large class of hyperbolic systems including the Oldyoryd-B model. This decay theorem is used to prove that global smooth solutions exist for small initial data. While small solutions are global, the problem for large data is much more complicated. I will present numerical work on the Oldroyd-B equations which indicates that the system develops singularities exponentially in time at hyperbolic stagnation points in the flow. The singularities arise in the stress field of the flow and the algebraic structure of these singularities depends critically on an important elasticity parameter, the Weissenberg number. A local approximation to the solution at the hyperbolic stagnation point is constructed and there is excellent agreement between the local solution and the simulations.