Date of Award

Spring 5-15-2016

Author's School

School of Engineering & Applied Science

Author's Department

Mechanical Engineering & Materials Science

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

Helicopters are generally limited in their performance by the phenomenon of dynamic stall. The purpose of this work is to develop a method for modeling dynamic stall that is appropriate to preliminary design and flight simulator applications. Unlike other semi-empirical dynamic stall models, the model developed in this thesis, not only counts for the well-known, three-dimensional flow effects on the stalled loads but also captures the secondary vortex-shedding phenomenon that has been seen in experiments. The fundamental physics that modify dynamic-stall behavior and that have been extended from two-dimensional to three-dimensional flow are, namely: 1.) yawed flow, 2.) time-varying velocity, 3.) the rotational environment and 4.) the radial blade coupling. For the reduced-order modeling, extra nonlinear states have been added to the dynamic stall model in order to simulate the double-dynamic-stall phenomenon. The results of this study will have practical applications to aerospace systems, such as compliant or morphing surfaces in rotary-wing systems that encounter transient or periodic separation and reattachment during phenomena such as dynamic stall.

Language

English (en)

Chair

David A. Peters

Committee Members

Swaminathan Karunamoorthy, Hiro Mukai, Shankar Sastry, Jessica Wagenseil,

Comments

Permanent URL: https://doi.org/10.7936/K7222S18

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