Computational Characterization and Classification of Transient Stall Events in Rotating Systems

Ph.D. Thesis Proposal

Amanda Grubb

11 a.m., Thursday, August 23

Montgomery Knight Building – Room 317

Abstract

Rotorcraft are highly complex dynamic systems and encounter a variety of aerodynamic phenomena not encountered by traditional fixed-wing aircraft.  One problem frequently encountered by rotorcraft is the appearance of stall events, which are transient due to the unsteady nature of rotating systems.  These complex aerodynamic phenomena are characterized by the convection of a strong vortex core along the rotor blade surface, and may include blade-vortex interactions and classic dynamic stall.  Large losses in lift and large negative pitching moments, both of which are detrimental to the integrity of the aircraft, appear during these events.  Fully understanding and being able to predict transient stall is of high importance as the rotorcraft community works towards next-generation vehicle design.

Most transient stall research to date has targeted two-dimensional analyses.  However, it has been shown that the inclusion of finite wing and rotational effects is necessary to fully capture and characterize stall behavior on rotorcraft.  Initial research into current computational approaches for analyzing stall on three-dimensional, rotating systems has identified several major shortcomings regarding turbulence and transition modeling, grid generation techniques, and the inclusion of aeroelastic effects.  The limitations of current computational approaches and recommendations to address these shortcomings are presented.

The proposed research goals are to address issues with the computational approaches that currently limit the ability to fully characterize and classify these transient stall events on rotating systems.  Those changes will be integrated and applied to new high-fidelity computational fluid dynamics and aeroelastic simulations to evaluate their effects when dynamic flow separation is encountered.  The approach will then be applied to available rotor geometries to establish an initial database which characterizes and classifies these events on rotating systems.

Committee

Prof. Marilyn Smith (Advisor), Georgia Institute of Technology, Aerospace Engineering

Prof. Ari Glezer, Georgia Institute of Technology, Mechanical Engineering

Mr. Rohit Jain, U.S. Army AMRDEC, Aviation Development Directorate

Dr. Marvin Moulton, U.S. Army AMRDEC, Aviation Engineering Directorate

Prof. Stephen Ruffin, Georgia Institute of Technology, Aerospace Engineering

Prof. Daniel Schrage, Georgia Institute of Technology, Aerospace Engineering