G. Paul Neitzel

Professor

Office:	Love, Room 229
Phone:	404.894.3242
Fax:	404.894.8496
E-mail:

Education

• Ph.D., The Johns Hopkins University, 1979
• M.S., The Johns Hopkins University, 1974
• B.S., Rollins College, 1969

Research Areas and Descriptors

• Fluid Mechanics and Heat Transfer, Combustion, and Energy Systems; Hydrodynamics stability, surface-tension-driven and rotating flows, noncoalescence and nonwetting, and bioreactor fluid dynamics

Background

Dr. Neitzel's research is in the area of fluid mechanics. His doctoral work was of a theoretical and numerical nature, studying the hydrodynamic instability of the problem called spin-down. He continued to work on the hydrodynamic stability of unsteady flows for several years and still maintains an interest in this area. In the mid-1980s, he began to conduct research on flows related to materials processing applications such as crystal growth from bulk melts. Such flows are strongly influenced by the phenomenon known as thermocapillarity, which is the variation of a liquid's surface tension with temperature. The instability of a type of convection driven by this is known to cause the appearance of dopant striations in silicon grown by the so-called "float-zone" crystal-growth process. Dr. Neitzel, his colleagues, and students have computed domains of stable and unstable flow in a model system and have also demonstrated, experimentally, how it may be possible to suppress the flow oscillations which lead to the above striations. Much of the work done by Dr. Neitzel since receiving his Ph.D. has been of an experimental nature; currently, experimental research makes up more than half of his current projects. He began at Tech in 1990 as a Professor. Prior, he was Assistant, Associate, and Professor at Arizona State University.

Research

Dr. Neitzel's research interests are in the area of the forced noncoalescence of liquids, an area that was stumbled upon in some recent space experiments, but which has been observed by others such as Lord Rayleigh as far back as the turn of the century. It turns out that thermocapillarity is one means by which two surfaces of the same liquid can be forced to remain apart. Such work has potential applications in microgravity environments as lowfriction bearings and perhaps in combustion. In addition, he is involved with a project in tissue engineering in bioreactors. The devices of interest are horizontal, rotating annuli in which constructs of tissues such as cartilage are grown. His group is involved with the measurement of the flow fields in these bioreactors and, through collaboration with others who are simulating these flow fields and growing tissues in controlled, low-shear environments as well as in the bioreactor, to constructing a mathematical model of tissue growth.

The work described here is funded through grants from the National Aeronautics and Space Administration. Earlier research has been funded by NASA, as well as by the National Science Foundation, the Office of Naval Research, and the Air Force Office of Scientific Research.

Distinctions

• National Aeronautics and Space Administration
  • On-Orbit Evaluation Board (International Space Station), 2000-present
  • Office of Biological and Physical Research Physical Sciences Advisory Subcommittee, 1997-present
  • Fluid Physics Discipline Working Group Chair, 1997-2002
  • Space Station Utilization Advisory Subcommittee Member, 1995-1999
• American Society of Mechanical Engineers Fellow, 2001
• Morehouse School of Medicine Space Medicine and Life Sciences Research Center External Advisory Board, 2000-present
• American Physical Society Fellow, 1994
• American Institute of Aeronautics and Astronautics Associate Fellow, 1990
• Alexander von Humboldt Foundation of Germany Research Fellowship, 1985
• National Science Foundation Presidential Young Investigator Award, 1984-1989

Representative Publications

• L. R. van den Doel, et al. 2005. Regularized Phase-Tracker with Iso-Phase Scanning Strategy for Analysis of Dynamic Interferograms of Nonwetting Droplets Under Excitation. Applied Optics 44, 2695-2704.
• P. Dell'Aversana and G. P. Neitzel. 2004. Behavior of Noncoalescing and Nonwetting Drops in Stable and Marginally Stable States. Experiments in Fluids 36, 299-308.
• P. Sucosky, et al. 2004. Fluid Mechanics of a Spinner-Flask Bioreactor. Biotechnology and Bioengineering 85, 34-46.
• L. B. S Summer, A. M. Wood, and G. P. Neitzel. 2003. Lubrication Analysis of Thermocapillary-Induced Nonwetting. Physics of Fluids 15, 2923-2933.
• G. P. Neitzel and P. Dell'Aversana. 2002. Non-coalescence of Liquids. Annual Review of Fluid Mechanics 34, 264-289.