Roy J. Hartfield, Jr.

Woltosz Professor, Aerospace Engineering

Research

• Modeling of Solid Rocket Motors

• Optimization of Missile and Launch Systems

Solid Rocket Motor Systems

Ramjet Systems

Liquid Rocket Systems

Earth to Orbit Launch Systems

Major Douglas Bayley finished his dissertation in 2007 under the direction of Dr. Hartfield and has authored a paper along with Dr. Hartfield, Dr. John Burkhalter and Dr. Rhonald Jenkins on the topic launch system optimization.   The paper was presented April 23, 2007 at the AIAA Multidisciplinary Optimization Conference in Honolulu, Hawaii.  Additionally, an ongoing effort to investigate aero-assist during early launch has lead to promising results.

• Development of Propeller Drive Mechanism

During 2006-2008, Christoph Burger and Roy Hartfield developed a drive mechanism which allows variable pitch propellers to automatically operate with near constant torque settings over a wide range of forward flight conditions.  This concept was described in a paper presented at the 25th AIAA Applied Aerodynamics meeting in Miami, FL in June, 2007.  This technology is particularly attractive to the small sport aircraft market and to the growing UAV industry.  A Canadian company, Aerovate, has licensed this technology and is developing products based on the technology for both of these important markets.  An image of the AU developed prototype is shown below.

• Optimization of Wind Turbines and Propellers

Christoph Burger completed a PhD student in Aerospace Engineering in 2007 pursuing a project to optimize the propulsion system and air frame for an organic aerial vehicle (OAV).  This effort has included an excursion into the field of wind turbines and a spin-off of this effort will include a tool for optimizing full scale aircraft propellers.  The technical approach used in this effort has been to model the performance of propeller and wind turbine blades using vortex lattice theory and then allow a genetic algorithm to select an optimum design by selecting blade geometry parameters and driving the vortex lattice code to produce performance data for candidate designs.   Some sample results from a paper  presented at the 4^th AIAA Energy Conversion Conference in San Diego, CA in June 2006 on the topic of wind turbine optimization are shown below.  In this figure, the wake of an optimized wind turbine blade is depicted.

• Freight Truck Drag Reduction

The Aerospace Engineering Department at Auburn University is involved in an ongoing effort to fundamentally advance the design process for highway tractor trailer rigs by including design optimization tooling directly in the aerodynamic shape design process.  This activity is taking a unique step forward for tractor trailer design by coupling performance evaluation using Computational Fluid Dynamics (CFD) with a genetic algorithm (GA).  Sample results obtained in collaboration with Josh Doyle and Dr. Chris Roy are shown below.

• Specialized testing of Component Drag

A significant effort involving wind tunnel testing of specially designed models to determine the drag induced by any given protuberance has been developed and is ongoing as necessary to support the Air Force special forces C-130 aircraft development.   A paper describing the methods used in this effort was presented at the AIAA Aerospace Sciences meeting in Reno NV in January 2005.

• Nonintrusive Optical Diagnostics

• Analysis of Launch Vehicle Aeroacoustics

In fall 2007, Auburn University was asked by NASA’s Constellation Program to participate in a synergistic effort to make an independent assessment of CEV/CLV Ares I ascent turbulent flow pressure fluctuations with an initial emphasis on the pressure fluctuation levels.  High levels of turbulent pressure fluctuations near critical areas of the vehicle, which are associated with high dynamic pressures, are of great concern during the initial two minutes of a typical launch trajectory. The problem can be considered to have three major components. First, the prediction of the overall pressure fluctuation level and identification of the areas of greatest fluctuations are matters of fundamental importance.  Second, the frequency content of the turbulent pressure fluctuation phenomena is of critical importance because of the potential coupling between the fluid mechanics and the vehicle structural vibrations.  Structural resonance conditions can lead to disastrous consequences for the structure and must be avoided.  Third, the instantaneous spatial distribution of the pressure fluctuations is needed for realistic predictions of structural vibrations.  This synergistic effort has been divided into three time periods of work with the first time period devoted to the assessment of the overall turbulent pressure fluctuation levels. 

• SCRAMJET Propulsion

The study of fuel-air mixing in a supersonic cross-flow has been looked at as potential scramjet combustor geometry. With the development of computing technology, it is possible to develop optimized preliminary designs for scramjet combustors using a CFD solver and a Genetic Algorithm. Experimental results from research conducted in the 1990s have been used for the validation of the CFD solutions. The experiments were highly focused on developing accurate data sets for a single case flow situation. This effort builds on this single validated case by considering geometric variations of the combustor design, solving for the flow and arriving at a geometry which is optimized for mixing efficiency with minimum total pressure loss under the direction of a Genetic Algorithm (GA).

• Optimal Rotorcraft Design

• Hypersonic Vehicle Design

X-43 Validation Case

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