Woodruff School of Mechanical Engineering

Faculty Candidate Seminar

Title:

Vortex-induced vibration of a linearly-sprung cylinder with nonlinear energy sinks

Speaker:

Dr. Antoine Blanchard

Affiliation:

Massachusetts Institute of Technology, Department of Mechanical Engineering

When:

Monday, November 27, 2017 at 11:00:00 AM

Where:

MARC Building, Room Auditorium

Host:

Dr. Julien Meaud

julien.meaud@me.gatech.edu

4043851301Abstract

We investigate the effect of coupling an essentially nonlinear and dissipative element to a linearly-sprung circular cylinder undergoing vortex-induced vibration (VIV) transverse to the mean flow. The nonlinear dissipative element is a “nonlinear energy sink” (NES), whose interaction with the flow is mediated by the cylinder. Essentially nonlinear coupling between the rectilinear motion of the cylinder and the motion of the NES allows for efficient, one-way transfer of kinetic energy from the former to the latter, where it is dissipated through a process known as “targeted energy transfer.” We use a spectral-element approach to compute the flow and the rigid-body quantities, and show that for values of the Reynolds number in the laminar regime (less than 100), the NES can give rise to a range of qualitatively new phenomena not seen in NES-less VIV. These include partial stabilization of the vortex street, considerable drag reduction, coexistence of multiple long-time solutions, complex bifurcation mechanisms, and complete suppression of fully-developed VIV. The computational results are investigated analytically using reduced-order models, thus providing insight into the nonlinear dynamics of the infinite-dimensional coupled system.

Biography

Antoine Blanchard is currently a postdoctoral associate at the Massachusetts Institute of Technology (MIT). He received his Ph.D. in Aerospace Engineering from the University of Illinois at Urbana—Champaign, and his B.S. and M.S. degrees from the Ecole Centrale de Lille in France. His current research focuses on prediction and quantification of extreme events in fluid—structure interaction problems.