STEPHEN M. RUFFIN, Ph.D.

Georgia Institute of Technology

School of Aerospace Engineering

Atlanta, GA 30332-0150

voice: (404) 894-8200

fax: (404) 894-2760

email: stephen.ruffin@aerospace.gatech.edu

 

NASCART-GT Cartesian Grid flow Solver: nascart

 

EARNED DEGREES

 

University                                                                           Field                                                                      Degree Year

Stanford University                                          Aeronautics and Astronautics                      Ph.D.     1993

Massachusetts Institute of Technology                      Aeronautics and Astronautics                      M.S.        1987

Princeton University                                                        Mechanical and Aerospace Eng.  B.S.E.     1985

 

EMPLOYMENT HISTORY

 

                                        Georgia Institute of Technology                                                         Atlanta, GA

9/99 - Present             Associate Professor, School of Aerospace Engineering

7/93 - 8/99                 Assistant Professor, School of Aerospace Engineering

 

                                        Massachusetts Institute of Technology                                            Cambridge, MA

9/00 - 8/01                 Visiting  Associate Professor, Aeronautics and Astronautics

 

                                        NASA Ames Research Center                                                             Moffett Field, CA

6/87 - 6/93                 Aerospace Engineer, Thermosciences Division

 

                                        Massachusetts Institute of Technology                                            Cambridge, MA

9/85 - 5/87                 Aerospace Scientist, Computational Fluid Dynamics Laboratory

 

                                        NASA Lewis Research Center                                                            Cleveland, OH

6/85 - 8/85                 Aerospace Engineer, Internal Fluid Mechanics Division

6/84 - 8/84                 Aerospace Engineer, Propulsion Systems Division

 

                                        Princeton University                                                                               Princeton, NJ

9/84 - 2/85                 Researcher, Space Propulsion Laboratory

9/83 - 4/84                 Researcher, Space Propulsion Laboratory

 

EXPERIENCE SUMMARY

 

                Dr. Ruffin is a specialist in compressible flow aerodynamics, airframe propulsion integration and in high temperature gas dynamics.  He has accumulated valuable experience in developing and applying computational fluid dynamics methods to a variety of flow fields.

                He is conducting sponsored research studies of a novel channel concept which provides increased lift/drag ratios and reduced sonic boom relative to conventional blunted geometries.  Dr. Ruffin is leading several computational and experimental studies in a NASA ballistic range of blunted re-entry vehicles and noses employing this concept.

                He has developed a unique “dynamically slotted” rotor which is designed to reduce the occurrence of dynamic stall on rotorcraft.  He serves as principal investigator of a project sponsored by the National Rotorcraft Technology Center which investigates this approach.

                Dr. Ruffin also leads a collaborative effort with Georgia Tech Research Institute in significant modification of a plume flow computer code.  Coupled fluid/particle physics and non-equilibrium flow capability are incorporated to significantly enhance accuracy of predictions of infrared and ultraviolet emissions from solid rocket motors and aircraft afterburners.  As principal investigator of the NASA Ames 3-D NASP Nozzle Simulation Project he developed a 3-D Navier-Stokes computer program for accurately predicting the propulsive exhaust flow and its interaction with a generic afterbody region.  The computed results were used to help design a wind tunnel experiment which modeled the nozzle/afterbody flow field.

                Dr. Ruffin is also conducting research on high speed, high temperature flows in which vibrational energy modes are substantially excited and in which chemical non-equilibrium exists.  Applications for this work include internal flows undergoing combustion, ascent vehicles, and vehicles which cruise at high speed.  Dr. Ruffin has developed a novel thermo-chemical model which provides improved predictions in these types of flows.  Properly modeling these real-gas effects is found to improve the accuracy of predictions of aerodynamic heating and aerodynamic force coefficients.

                As a researcher in the computational fluid dynamics laboratory at MIT, Dr. Ruffin conducted studies of viscous-inviscid interaction on vortex dominated hypersonic flows over delta wings.  This work involved developing an accurate and efficient, Navier-Stokes solver for vortex flow analysis.

                Through experience at Princeton University and at NASA Ames and Lewis Research Centers Dr. Ruffin has gained valuable experience in a variety of other areas.  These areas include studies of basic fluid mechanics phenomenon such as turbulent boundary layer behavior on curved surfaces and boundary layer transition.  Dr. Ruffin has also analyzed aerodynamic performance degradation due to ice formation on airfoils using computational techniques and experimental results.

 

PUBLICATIONS

 

Refereed Publications

 

1.        Ruffin, S.M., Hypersonic Viscous Solutions for Flow over Delta Wings, MIT M.S. Thesis, May 1987.

 

2.        Ruffin, S.M., "Solutions for Hypersonic Viscous Flow Over Delta Wings," MIT CFDL TR 87-4, pp. 1-102, May 1987.

 

3.        Ruffin, S.M., Venkatapathy, E., Keener, E.R., Spaid, F.W., "Hypersonic Single Expansion Ramp Nozzle Simulations," Journal of Spacecraft and Rockets, Vol 29, No. 6, pp. 749-755, November-December 1992.

 

4.        Ruffin, S.M., Vibrational Energy Transfer of Diatomic Gases in Hypersonic Expanding Flows, Stanford University Ph.D. Thesis, June 1993.

 

5.        Ruffin, S.M., "Vibrational Energy Transfer of Diatomic Gases in Hypersonic Expanding Flows," Stanford University Department of Aeronautics and Astronautics Report No. 635, pp. 1-175, June 1993.

 

6.        Ruffin, S.M., and Park, C., "Vibrational Relaxation of Anharmonic Oscillators in Expanding Flows," Journal of Spacecraft and Rockets, Vol. 30, No. 1, pp. 59-68, January-February 1993.

 

7.        Sharma, S.P., Ruffin, S.M., Meyer, S.A., Gillespie, W.D., Yates, L.A., "Density Measurements in an Expanding Flow Using Holographic Interferometry," Journal of Thermophysics and Heat Transfer, Vol. 7, No. 2, pp. 261-268, April-June 1993.

 

8.        Sharma, S.P., Ruffin, S.M., Gillespie, W.D., Meyer, S.A., "Vibrational Relaxation Measurements in an Expanding Flow Using Spontaneous Raman Scattering," Journal of Thermophysics and Heat Transfer, Vol. 7, No. 4, pp. 697-703, October-December 1993.

 

9.        Ruffin, S.M., "Prediction of Vibrational Relaxation in Hypersonic Expanding Flows - Part I: Model Development," Journal of Thermophysics and Heat Transfer, Vol. 9, No. 3, July-Sept 1995.

 

10.    Ruffin, S.M., "Prediction of Vibrational Relaxation in Hypersonic Expanding Flows - Part II: Results," Journal of Thermophysics and Heat Transfer, Vol. 9, No. 3, July-Sept 1995.

 

11.    Ruffin, S.M., Gupta, A. and Marshall, D., “Supersonic Channel-Airfoils for Reduced Drag,” AIAA Journal, Vol. 38, No. 3, Mar., 2000, pp. 480-486.

 

12.    Gupta, A., and Ruffin, S.M., “Aerothermodynamic Design of Supersonic Channel-Airfoils for Drag Reduction,” Journal of Aerospace – SAE 1997 Transactions, Vol. 106, Section I, July, 1997, pp. 1647-1656.

 

13.    Gupta, A., Ruffin, S.M., “Optimal Artificially Blunted Leading Edge (ABLE) Airfoils for Hypersonic Performance Enhancement,” Journal of Spacecraft and Rockets, Vol. 36, No. 4, pp. 499-506, July-Aug., 1999.

 

14.    Gupta, A., Ruffin, S.M., Newfield, M., and Yates, L, “Aerothermodynamic Performance Enhancement and Design of Blunted Sphere-Cones using the ABLE Concept,” Journal of Spacecraft and Rockets, Vol. 37, No. 2, Mar.-Apr. 2000.

 

  1. Gupta, A. and Ruffin, S.M. “Investigation of Artificially Blunted Leading Edge Geometries with Curved Channels for High Speed Drag Reduction,” Submitted to Journal of Spacecraft and Rockets, February, 2000.

 

  1. Josyula, E, Bailey, W.F., and Ruffin, S.M., “Role of Reactive and Non-Reactive Vibrational Energy Exchanges in Nonequilibrium Hypersonic Flows, Physics of Fluids, Vol. 15, No. 10, Oct. 2003.

 

24.    Tu, Shuangzhang, Ruffin, S.M., "Solution Adaptive, Unstructured Cartesian-Grid Methodology for Chemically Reacting Flows", Submitted to Journal of Thermophysics and Heat Transfer, April, 2003.

 

  1. Tu, Shuangzhang, Ruffin, S.M., "Calculation of Nonequilibrium Flows Using a Solution Adaptive, Unstructured Cartesian-Grid Methodology", Submitted to Journal of Thermophysics and Heat Transfer, April, 2003

 

Patents and Invention Disclosures

  1. Patent: Ruffin, S.M., “Leading Edge Channel for Enhancement of Lift/Drag Ratio and Reduction of Sonic Boom, AWARDED: October 15, 2002

 

  1. Software Disclosure, “Numerical Aerodynamics Simulation via CARTesian Grid Techniques: NASCART-GT,” February 11, 2003.

 

Other Publications

 

  1. Ruffin, S.M., Murman, E., "Solution for Hypersonic Viscous Flow Over Delta Wings, "AIAA Paper 88-0126, January 1988.

 

  1. Spaid, F.W., Keener, E.R., Ruffin, S.M., Venkatapathy, E., " Aspects of a Hypersonic Nozzle/Afterbody and Code Validation Experiment," 5th National Aero-Space Plane Symposium, Paper No.   50, October 1988.

 

  1. Ruffin, S.M., Venkatapathy, E., Keener, E.R., Nagaraj, N., "Computational Design Aspects of a NASP Nozzle/Afterbody Experiment," AIAA Paper 89-0446, January 1989.

 

  1. Ruffin, S.M., Venkatapathy, E., Feiereisen, W.J., Lee, S.H., "Progress in Computing Nozzle/Plume Flow Fields," Proceedings of the NASA Computational Fluid Dynamics Conference at NASA Ames, NASA Conference Publication 10038, Vol. 2, March 1989.

 

  1. Venkatapathy, E., Ruffin, S.M., Lee, S.H., Deiwert, G.S., Feireisen, W.J., "Development and Applications of a Nozzle/Afterbody Flow Solver," NASP CR 1068, January 1990.

 

  1. Spaid, F.W., Keener, E.R., Ruffin, S.M., "Experimental Results and CFD Code Validation for a Hypersonic Nozzle / Afterbody Flow Field," 9th National Aero-Space Plane Symposium, Paper No. 123, November 1990.

 

  1. Ruffin, S.M., Venkatapathy, E., Tokarcik, S., Lee, S.H., Spaid, F., Keener, E.R., Feiereisen, W.J., "Development and Validation of the F3D/Nozzle Code," 10th National Aero-Space Plane Symposium, Paper No. 142, April 1991.

 

  1. Ruffin, S.M., "Solutions for Hypersonic Viscous Flow over Delta Wings," NASA Tech Briefs, Vol. 15, No. 12, ARC 12179, December 1991.

 

  1. Ruffin, S.M., Venkatapathy, E., Lee, S.H., Keener, E.R., Spaid, F.W., "Single Expansion Ramp Nozzle Simulations," AIAA paper 92-0387, January 1992.

 

  1. Ruffin, S.M., and Park, C., "Vibrational Relaxation of Anharmonic Oscillators in Expanding Flows," AIAA Paper 92-0806, January 1992.

 

  1. Sharma, S.P., Ruffin, S.M., Meyer, S.A., Gillespie, W.D., Yates, L.A., "Density Measurements in an Expanding Flow Using Holographic Interferometry," AIAA Paper 92-0809, January 1992.

 

  1. Sharma, S.P., Ruffin,  S.A., Gillespie, S.M., Meyer,W.D., "Nonequilibrium Vibrational Population Measurements in an Expanding Flow Using Spontaneous Raman Scattering," AIAA Paper 92-2855, July 1992.

 

  1. Gillespie. W.D., Bershader, D., Sharma, S.P., Ruffin, S.M., "Raman Scattering Measurements of Vibrational and Rotational Distributions in Expanding Nitrogen," AIAA Paper 93-0274, January 1993.

 

  1. Ruffin, S.M., "Prediction of Vibrational Relaxation in Hypersonic Expanding Flows," AIAA Paper 94-0456, January 1994.

 

  1. Ruffin, S.M. and Gupta, A., “Supersonic Channel-Airfoils for Reduced Drag,” AIAA Paper 97-0517, January 1997.

 

  1. Newfield, M. and Ruffin, S.M., “Validation of a Nose Channel Concept for Supersonic Drag Reduction,” NASA TM-1998-112216, October 1997.

 

  1. Gupta, A., Ruffin, S.M., “Aerothermodynamic Design of Supersonic Channel-Airfoils for Drag Reduction,” SAE International, World Aviation Congress Paper 97WAC-49, October, 1997.

 

18.    Gupta, A., Ruffin, S.M. and Newfield, M. “Aerothermodynamic Performance Enhancement and Design of Blunted Sphere-Cones using the ABLE Concept,” AIAA Paper 99-0897, January, 1999.

 

19.    Gupta, A. and Ruffin, S.M. “Investigation of Artificially Blunted Leading Edge Geometries with Curved Channels for High Speed Drag Reduction,” AIAA Paper 2000-0901, January, 2000.

 

20.    Tam, T., Ruffin, S., Gage, P., Bogdanoff, D., Yates, Y., Morgenstern, J., “Sonic Boom Testing of Artificially Blunted Leading Edge (ABLE) Concepts in the NASA Ames Aeroballistic Range,” AIAA Paper 2000-1011, January, 2000.

 

21.    Gupta, A., Ruffin, S.M., "Application of the Artificially Blunted Leading Edge Concept for Directional Control of High Speed Vehicles," AIAA Paper 2000-2598, June, 2000.

 

22.    Chen, L, and Ruffin, S.M., "Evaluation of Multi-Element Airfoils for Dynamic Stall Mitigation," AHS Aeromechanics Specialists Meeting, Atlanta, GA, November, 2000.

 

23.    Marshall, D., Aftosmis, M.J., and Ruffin, S.M., "Study of Parallelization Enhancements for Cartesian Grid Solver," International Conf. on Parallel CFD, May, 2002.

 

24.    Tu, Shuangzhang, Ruffin, S.M., "Solution Adaptive, Unstructured Cartesian-Grid Methodology for Chemically Reacting Flows", AIAA Paper 2002-3097, June, 2002.

 

  1. Tu, Shuangzhang, Ruffin, S.M., "Calculation of Nonequilibrium Flows Using a Solution Adaptive, Unstructured Cartesian-Grid Methodology", AIAA Paper 2002-3098, June, 2002.

 

  1. Josyula, E, Bailey, W.F., and Ruffin, S.M., “Role of Reactive and Non-Reactive Vibrational Energy Exchanges in Nonequilibrium Hypersonic Flows, AIAA Paper 2002-3220, June 2002.

 

  1. Ruffin, S.M., O’brien, D.O., Smith, M.J., Hariharan, N., Lee, J.D., Sankar, L.N, “Comparison of Rotor-Airframe Interaction Predictions Utilizing Overset and Unstructured Grid Techniques AIAA Paper 2004-0046, Jan., 2004.

 

28.    Marshall, D., and Ruffin, S.M., "A New Inviscid Wall Boundary Condition Treatment for Embedded Boundary Cartesian Grid Schemes,” AIAA Paper 2004-0583 Jan. 2004.

 

29.    Marshall, D., and Ruffin, S.M., " An Embedded Boundary Cartesian Grid Scheme for Viscous Flows using a New Viscous Wall Boundary Condition Treatment,” AIAA Paper 2004-0581 Jan. 2004.

 

 

SERVICE

 

Professional Contributions

 

1.        Member, American Institute of Aeronautics and Astronautics, 1989-present

2.        Speaker, NASA Educational Programs Office , 1989-1993

3.        Member, NASA Ames Equal Opportunity Council, 1988-1990

4.        Chairperson (Elected), NASA Ames African American Advisory Group, 1989-1990.

5.        Member, NASA Historically Black Colleges and Universities Research Center Selection Team, 1992

6.        Treasurer (Elected), NASA Ames African American Advisory Group, 1990-1993.

7.        Session Chairperson, AIAA Aerospace Science Meeting, 1995

8.        Member, NASA Education, Training and Lifelong Learning Review Panel, 1995

9.        Participant, ASEE Minority Faculty Development Forum, 1995

10.    Participant, 5th ASEE National Teaching Effectiveness Institute, 1995

11.    Workshop Coordinator, Mathematics in Physics and Aeronautics Pilot Program, Morehouse College, 1995

12.    Reviewer, AIAA Journal, 1988-1990

13.    Reviewer, Journal of Thermophysics and Heat Transfer, 1991-present

 

Campus Contributions

1.        Member, Georgia Tech Fluid Mechanics Seminar Colloquium Committee, 1993-1994

2.        Faculty Representative, New Student Orientation sponsored by Georgia Tech Black Graduate Students Association, 1993

3.        Georgia Tech Black Graduate Students Association, 1993

4.        Member, Aerodynamics and Fluid Mechanics Discipline Committee, 1993-present

5.        Keynote Speaker at Graduate Student Colloquium sponsored by Georgia Tech Black Graduate Students Association, 1994

6.        Member, Aerodynamics and Fluid Dynamics Faculty Search Committee, 1994

7.        Faculty Advisor at AIAA Regional Student Conference, 1994.

8.        Speaker at Society of Black Engineers High School Ambassador's Day, 1994

9.        AE Faculty Representative, Focus '95 sponsored by Georgia Tech College of Engineering, 1995

10.    AE Representative (Elected), General Faculty Assembly, 1994 -1997

11.    Member, AE Graduate Committee, 1995-present

12.    Judge, Debate sponsored by Xi Alpha Chapter of Delta Sigma Theta Sorority, Inc., 1995

13.    Member, Undergraduate Enrollment Enhancement Committee, 1995-present

14.    AE Faculty Representative, Focus '96 sponsored by Georgia Tech College of Engineering, 1996

15.    Participant, GTRI Mentor/Mentee Program, 1995-1996

16.    Member (Elected), AE Advisory Committee, 1995-present

17.    AE Faculty Representative, Focus '97 sponsored by Georgia Tech College of Engineering, 1997

18.    Facilitator, Georgia Tech LeaderShape Institute, 1997

19.    Workshop Coordinator, Univ. System of Ga. Leadership Development and Minority Recruitment Conference, 1997, 1998, 1999

20.    Member, Reappointment Promotion and Tenure Committee, College of Engineering, 2002-2004

21.    Member, College of Engineering, Peer Evaluation of Teaching Effectiveness Committee, 2003-present

22.    Representative (Elected), Student Honor Committee, 2003-2005

 

Consulting

1.        Barron, Inc., Design and analysis of jet eductors, 1995-1996

2.        Diamond Power Inc., Analysis and testing of soot blower nozzles, 1999-2002

 

Professionally-Related Civic Activities

1.        Member, Executive Round Table, 1995-present

2.        Judge, ACSI State Science Fair, 1994, 1996

3.        Event Coordinator, Aerodynamics Aloft Competition in Science Olympiad State Tournament, 1995

 

HONORS AND AWARDS

 

1.        Consortium for Graduate Degrees for Minorities in Engineering (GEM) Fellowship, 1984-1987

2.        Nominee, Black Engineer of the Year - U.S. Black Engineer Magazine, 1991

3.        NASA Superior Performance Award, 1992

4.        NASA National Aerospace Plane CFD Validation Team Award, 1992

5.        NASA Historically Black Colleges & Universities Research Center Team Award, 1992

6.        NASA College Recruitment Award, 1993

7.        AIAA Best Thermophysics Paper Award, 1993

8.        CETL/Amoco Junior Faculty Teaching Excellence Award, 1997

9.        Meritor Inc. Faculty Excellence Award, 2000