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MAE SEMINAR SERIES

From Compliant Coatings to Vocal Fold Vibration:  Dealing With Complex Moving Boundaries in Fluid-Structure Interaction

Dr. Haoxiang Luo
Postdoctoral Research Scientist
Mechanical & Aerospace Engineering
The George Washington University

Thursday, February 9, 2006, 1pm
Phillips Hall 7th Floor Conference Room #736

ABSTRACT:
Quite a few approaches are available for solving complex/moving boundary problems in computational mechanics. In this talk, I will cover three physical problems and talk about the different approaches used to effectively deal with the boundary issues.  In the first problem, the interaction of a compliant coating and near-wall turbulence is computed using direct numerical simulations.  Inspired from nature, the compliant coating is modeled as a special truss system having tensile members distinguished from the compressive members.  It was found that for some parameters, the coating resonates under the excitation of the flow disturbances, and both the turbulence intensity and drag on the compliant surface are increased significantly.
 
In the second problem, we investigate the stability of the core-annular flow of two immiscible fluids which has an application in lubricated pipeline transport.  The flow may fall prey to the Rayleigh capillary instability leading to the deposition of the outer fluid into annular lobes, or to dispersion of drops of the core fluid.  The effect of an insoluble surfactant on the stability is considered.  An immersed-boundary method is used to simulate the nonlinear evolution of the fluid-fluid interface.

Finally, I will spend some time talking about an ongoing study on vocal fold modeling. In this work, a new immersed-boundary method used in the CFD is extended to model the viscoelastic behavior of vocal folds in order to simulate laryngeal aerodynamics and vocal fold vibrations. All governing equations for the flow and solid are solved on a Cartesian grid.  The numerical method and preliminary results will be presented.

Biographical Sketch:
Dr. Haoxiang Luo is currently a Postdoctoral Research Scientist at The George Washington University’s Department of Mechanical and Aerospace Engineering.  He obtained his BS and MS from Tsinghua University, Beijing, and received a Phd from the University of California, San Diego in 2004.  After graduating, he stayed in UCSD for one more year as a Postdoctoral student before joining the GW.