Title

Advanced numerical techniques for accurate unsteady simulations of a wingtip vortex

Author

Shakeel Ahmad

Advisor

Janus, Mark Jonathan

Committee Member

Lim, Hyeona

Committee Member

Banicescu, Ioana

Committee Member

Koenig, Keith

Date of Degree

5-1-2010

Original embargo terms

MSU Only Indefinitely

Document Type

Dissertation - Open Access

Degree Name

Doctor of Philosophy

Abstract

A numerical technique is developed to simulate the vortices associated with stationary and flapping wings. The Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations are used over an unstructured grid. The present work assesses the locations of the origins of vortex generation, models those locations and develops a systematic mesh refinement strategy to simulate vortices more accurately using the URANS model. The vortex center plays a key role in the analysis of the simulation data. A novel approach to locating a vortex center is also developed referred to as the Max-Max criterion. Experimental validation of the simulated vortex from a stationary NACA0012 wing is achieved. The tangential velocity along the core of the vortex falls within five percent of the experimental data in the case of the stationary NACA0012 simulation. The wing surface pressure coefficient also matches with the experimental data. The refinement techniques are then focused on unsteady simulations of pitching and dual-mode wing flapping. Tip vortex strength, location, and wing surface pressure are analyzed. Links to vortex behavior and wing motion are inferred.

URI

https://hdl.handle.net/11668/16296

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