George Vradis

Associate Professor

George Vradis
National Technical University of Athens, Greece

Bachelor of Science,

Polytechnic Institute of New York University

Master of Science,

Polytechnic Institute of New York University

Doctor of Philosophy,


Journal Articles


Peer Reviewed Journal Publications

  • K.J. Hammad, M.V. Otugen, G.C. Vradis, and E.B. Arik, "Laminar Flow of a Non-Linear Viscoplastic Fluid Through an Axisymmetric Sudden Expansion", Journal of Fluids Engineering, (in review).
  • I.H. Jafri and G.C. Vradis, "The Evolution of Laminar Jets of Herschel-Bulkley Fluids", International Journal of Heat and MassTransfer, Vol. 41, 1998, pp. 3575-3588.
  • K.J. Hammad and G.C. Vradis, "Asymptotic Flow Regimes in Pulsatile Flows of Bingham Plastics", Journal of Fluids Engineering, Vol. 120, No. 1, March 1998, pp. 211-213.
  • G.C. Vradis and K.J. Hammad, "A Strongly-Coupled Bolck-Implicit Solution Technique for Non-Newtonian Convective Heat Transfer Problems", Numerical Heat Transfer- Fundamentals, Part B, Vol. 33, 1998, pp. 79-97.
  • K.J. Hammad, F.Y. Wang, M.V. Otugen, and G.C. Vradis, "Suddenly Expanding Axisymmetric Flow of a Yield-Stress Fluid", 1997 Album of Visualization, No. 14, 1997, pp. 18.
  • G.C. Vradis and M.V. Otugen, "Flow of Non-Newtonian Viscoplastic Fluids Over a Sudden Expansion in a Pipe", Journal of Fluids Engineering, Vol. 119, No. 1, March 1997, pp. 193-200.
  • K.J. Hammad and G.C. Vradis, "Dissipative Cylindrical Couette Flow of Yield-Pseudoplastic Fluids", International Journal of Heat and MassTransfer, Vol. 40, No. 5, 1997, pp. 1243-1248.
  • V.M. Gold, G.C. Vradis, and J.C. Pearson, "Concrete Penetration by High Velocity Projectiles: The Effect of Yield-Strength Modelling", Mathematical Modelling and Scientific Computing, Vol. 6, No. 1, 1996.
  • K.J. Hammad and G.C. Vradis, "Viscous Dissipation and Heat Transfer in Pulsating Flows of a Yield-Stress Fluid", International Communications in Heat and Mass Transfer, Vol. 23, No. 5, 1996, pp. 599-612.
  • G.C. Vradis and K.J. Hammad, "Inertia Effects on the Flow of Bingham Plastics Through Sudden Contractions in a Pipe", Canadian Journal of Chemical Engineering, Vol. 74, No. 4, 1996.
  • K.J. Hammad and G.C. Vradis, "Creeping Flow of a Bingham Plastic Through Axisymmetric Sudden Contractions with Viscous Dissipation", International Journal of Heat and Mass Transfer, Vol. 39, No. 8, 1996, pp. 1555-1568.
  • V.M. Gold, G.C. Vradis, and J.C. Pearson, "Study of Constitutive Models for Concrete Penetration Analysis", ASCE Journal of Engineering Mechanics, Vol. 122, No. 3, 1996, pp. 230-238.
  • V.M. Gold, G.C. Vradis, and J.C. Pearson, "Concrete Penetration of Eroding Projectiles: Experiments and Analysis", ASCE Journal of Engineering Mechanics, Vol. 122, No. 2, 1996, pp. 145-152.
  • G.C. Vradis and K.J. Hammad, "Heat Transfer in Flows of Bingham Fluids Through Axisymmetric Sudden Expansions and Contractions", Numerical Heat Transfer, Part A, Vol. 28, 1995, pp. 339-353.
  • S. Kumar and G.C. Vradis, "Thermal Conductivity of Thin Metallic Films by Electron Transport", Journal of Heat Transfer, Vol. 116, February 1994, pp. 28-34.
  • G.C. Vradis and M.V. Otugen, "Mixing of Multiple Coflowing Confined Laminar Streams", AIAA Journal of Thermophysics and Heat Transfer, Vol. 7, No. 3, July-September 1993, pp. 540-542.
  • G.C. Vradis, M.V. Otugen, S.W. Kim and D.B. Kim, "Round Incompressible Jets with Initially Asymmetric Velocity Distributions", AIAA Journal, Vol. 31, No. 5, May 1993, pp. 814-816.
  • M.V. Otugen, G. Papadopoulos, G.C. Vradis and G. Muckenthaler, "Spanwise Characteristics of the Separated Flow in a Suddenly Expanding Duct", Experiments in Fluids, Vol. 13, No. 2, March 1993, pp. 213-216.
  • G.C. Vradis, J. Dougher and S. Kumar, "Entrance Pipe Flow and Heat Transfer for a Bingham Plastic", International Journal of Heat and Mass Transfer, Vol. 36, February 1993.
  • G.C. Vradis and A.L. Protopapas, "Macroscopic Conductivities for Flows of Bingham Plastics in Porous Media", ASCE Journal of Hydraulics Engineering, Vol. 119, No. 1, January 1993, pp. 95-108.
  • G.C. Vradis, V. Zalak and J. Bentson, "Simultaneous Variable Solutions of the Incompressible Steady Navier-Stokes Equations in General Curvilinear Coordinate Systems", ASME Journal of Fluids Engineering, Vol. 114, September 1992, pp. 299-305.
  • G.C. Vradis and L. Van Nostrand, "Laminar Coupled Flow Downstream of an Asymmetric Sudden Expansion", AIAA Journal of Thermophysics and Heat Transfer, Vol. 6, No 2, April-June 1992, pp. 288-295.
  • J. Bentson and G.C. Vradis, "A Two-Stage Pressure Correction Technique for the Incompressible Navier-Stokes Equations", AIAA Journal, Vol. 28, July 1990, pp. 1155-1156.

Authored/Edited Books


  • Editor, Flows in Manufacturing Processes, 1998, American Society of Mechanical Engineers.
  • Editor, Laminar Flows, 1998, American Society of Mechanical Engineers.
  • Co-Editor, Separated and Complex Flows, 1997, American Society of Mechanical Engineers.
  • Editor, Laminar Flows, 1996, American Society of Mechanical Engineers.
  • Editor, Advances in Computational Heat Transfer, 1995, American Society of Mechanical Engineers.
  • Co-Editor, Separated and Complex Flows, 1995, American Society of Mechanical Engineers.
  • Editor, Numerical Methods for Non-Newtonian Fluid Dynamics, FED-Vol. 179, 1994, American Society of Mechanical Engineers.

Other Publications


Peer Reviewed Conference Papers

  • G.C. Vradis, "Metering Accuracy of Coriolis Mass Flow Meters in Natural Gas Vehicle Filling Stations", to be presented at the the 1998 International Gas Research Conference, San Diego, CA, November 8-11, 1998 (submitted).
  • K.J. Hammad and G.C. Vradis, "Heat Transfer in Laminar Flow of Yield-Pseudoplastic Fluid Over an Axisymmetric Sudden Expansion", to be presented at the Symposium on Fundamentals of Heat Transfer in Separated Flows, 1998 AIAA/ASME Joint Thermophysics and Heat Transfer Conference, Albuquerque, NM, June 15-18, 1998.
  • G.C. Vradis, "Flow of Yield-Stress Fluids in Complex Geometries", Rheology and Fluid Mechanics of Non-Linear Materials, ASME FED-Vol. 243, MD-Vol. 78, Eds: S.G. Advani and D.A. Siginer, 1997, pp.143-150 (Invited Paper at the 1997 ASME IMEC&E, Dallas, TX, November 16-21, 1997).
  • G.C. Vradis and K.J. Hammad, "A Strongly Coupled Block-Implicit Method for Non-Newtonian Flow/Heat Transfer Problems", Heat Transfer Symposium, Energy Week 1997, Houston, Texas, January 28-30, 1997.
  • K.J. Hammad, G.C. Vradis, and M.V. Otugen, "Laminar Flow of a Non-Newtonian Yield-Pseudoplastic Fluid Over an Axisymmetric Sudden Expansion", Proceedings of the 6th International Congress on Fluid Mechanics, Cairo, Egypt, December 29-31, 1996.
  • I.H. Jafri and G.C. Vradis, "The Evolution of Planar and Axisymmetric Yield/Power-Law Jets", Rheology and Fluid Mechanics of Nonlinear Materials, ASME AMD-Vol. 217, pp. 27-36, 1996.
  • K.J. Hammad, M.V. Otugen, G.C. Vradis, and E.B. Arik, "Laminar Axisymmetric Recirculating Flow of a Nonlinear Viscoplastic Fluid", Rheology and Fluid Mechanics of Nonlinear Materials, ASME AMD-Vol. 217, pp. 17-26, 1996.
  • V.M. Gold, G.C. Vradis, and J.C. Pearson, "Concrete Constitutive Modelling in High Velocity Penetration Analysis", Twentieth Army Science Conference; Award Winning Papers, World Scientific, Eds. R. Chait et al., pp. 98-104. Received "Best Paper Award in Engineering Sciences".
  • K.J. Hammad and G.C. Vradis, "Non-Isothermal Controlled Shearing Rate Rheometry of a Yield-Pseudoplastic Fluid: Effects of Shear Heating", Developments and Applications of Non-Newtonian Flows, ASME FED-Vol. 231, MD-Vol. 66, pp. 245-251, 1995.
  • K.J. Hammad and G.C. Vradis, "Viscous Dissipation and Heat Transfer in Pulsatile Flows of A Yield Stress Fluid", Proceedings of the Symposium on Thermal Science and Engineering in Honor of Chancellor Chang-Lin Tien, pp.19-26, San Francisco, California, November 14, 1995.
  • K. Hammad and G.C. Vradis, "Technology Assessment of Gas Turbine Combustors and Their Emissions", Proceedings of the 30th Intersociety Energy Conversion Engineering Conference, Vol. 2, pp.73-82, Orlando, Florida, July 31- August 4, 1995.
  • V.M. Gold, G.C. Vradis, and J.C. Pearson, "Concrete Constitutive Modelling in High Velocity Penetration Analysis", IAMCM 10th International Conference on Mathematical and Computer Modelling, Boston Massachusetts, July 5-8, 1995.
  • G.C. Vradis and K. Hammad, "Heat Transfer in Flows of Non-Newtonian Viscoplastic Fluids Through Sudden Expansions and Contractions in a Pipe", Proceedings of the 4th ASME/JSME Thermal Engineering Joint Conference, Vol. 1, pp. 285-294. Held in Maui, Hawaii, March 19-24, 1995.
  • G.C. Vradis, V. Otugen, and F. Girlea, "Studies Related to Gas Metering Accuracy in Natural Gas Vehicle Filling Stations", Proceedings of the 3rd International Symposium on Fluid Flow Measurement, San Antonio, Texas, March 20-22, 1995.
  • K. Hammad and G.C. Vradis, "Flow of a Non-Newtonian Bingham Plastic Through an Axisymmetric Sudden Contraction: Effects of Reynolds and Yield Numbers", Numerical Methods For Non-Newtonian Fluid Dynamics, ASME FED-Vol. 179, Editors: G.C. Vradis and D.A. Siginer, pp.63-70.
  • V.M. Gold, J.C. Pearson, and G.C. Vradis, "Numerical Simulations of Experiments on Penetration of Concrete Targets", Advances in Numerical Simulation Techniques for Penetration and Perforation of Solids, ASME AMD-Vol. 171, Editors: E.P. Chen and V.K. Luk, pp. 155-166.
  • J.G. Sanchez and G.C. Vradis, "Mixed Convection Heat Transfer Over A Backward Facing Step", Computational Aspects of Heat Transfer Benchmark Problems, ASME HTD-Vol. 258, Editors: B.F. Blackwell and B.F. Armaly, pp. 93-104.
  • G. Papadopoulos, M.V. Otugen, and G.C. Vradis, "Aspect Ratio Effects on the Centerplane Pressure and Flow Structure in a One-Sided Suddenly Expanding Duct", Separated Flows, ASME FED-Vol. 149, Editors: J.C. Dutton and L.P. Purtell, pp. 9-18.
  • G. Papadopoulos, M.V. Otugen, and G.C. Vradis, "Wall Pressure and Near Wall Velocity Studies on the Three-Dimensional Flow Over A Backward Facing Step," Proceedings of the First International Conference on Near-Wall Turbulence, Tempe, AZ, March 15-18, 1993.
  • G.C. Vradis and M.V. Otugen, "The Flow of a Bingham Plastic over a Sudden Expansion in a Pipe", ASME Winter Annual Meeting, Anaheim, CA, November 8-13, 1992, Recent Advances in Non-Newtonian Flows, ASME AMD-Vol. 153, Editor: D.A. Siginer, pp. 129-136.
  • G.C. Vradis and A.L. Protopapas, "Fundamental Relationships for Flows of Bingham Fluids in Porous Media", ASME Winter Annual Meeting, Anaheim, CA, November 8-13, 1992, Recent Advances in Non-Newtonian Flows, ASME FED-Vol. 141, Editor: D.A. Siginer, pp. 57-66.
  • G.C. Vradis, M.V. Otugen, and J.G. Sanchez, "Heat Transfer over a Backward Facing Step: Solutions to a Benchmark Problem", ASME Winter Annual Meeting, Anaheim, CA, November 8-13, 1992, Benchmark Problems for Heat Transfer Codes, ASME HTD-Vol. 222, Editors: B. Blackwell and D. W. Pepper, pp. 27-36.
  • S. Kumar and G.C. Vradis, "Thermal Conductivity of Thin Metallic Films by Electron Transport", National Heat Transfer Conference, San Diego, California, August 9-12, 1992, Heat Transfer on the Microscale, ASME HTD-Vol. 200, Editors: K.S. Udell et al., pp. 55-62.
  • S. Kumar and G.C. Vradis, "Thermal Conduction by Electrons Along Thin Films: Effects of Thickness According to Boltzmann Transport Theory", 1991 ASME Winter Annual Meeting, Atlanta, Georgia, December 1-6, 1991, Micromechanical Sensors, Actuators, and Systems, ASME DSC-Vol. 32, Editors: D. Cho et al., pp. 89-102.
  • G.C. Vradis and S. Kumar, "The Hydrodynamic and Thermal Entrance Flow Problem in a Pipe with Constant Wall Temperature for a Non-Newtonian Bingham Fluid", 1991 ASME National Heat Transfer Conference, Minneapolis, Minnesota, July 28-31, 1991, Convective Heat Transfer and Transport Process, ASME HTD-Vol.168, Editors: A.G. Lavine et al., pp. 9-15.
  • G.C. Vradis, V. Zalak and J. Bentson, "Strongly Implicit Solutions of the Incompressible Steady Navier-Stokes Equations in General Curvilinear Coordinate Systems", First ASME-JSME Fluids Engineering Conference, Portland, Oregon, June 23-26, 1991, General Topics in Fluids Engineering, ASME FED-Vol.107, Editors: F.M. White and K. Kamemoto, pp. 83-90.
  • G.C. Vradis and L. Van Nostrand, "Variable Viscosity Effects on the Laminar Flow and Heat Transfer Downstream Of a Backwards Facing Step", Winter Annual Meeting of the ASME, Dallas, Texas, November 25-30, 1990, Simulation and Numerical Methods in Heat Transfer, ASME HTD-Vol.157, Editor: A.F. Emery, pp. 1-8.


Research Interests


Computational fluid dynamics and heat transfer Non-Newtonian flows Flow measurement Combustion Energy systems