Home Page for John Mahaffy
Department
of Mechanical and Nuclear Engineering
and the
Applied Research
Laboratory
Computational Mechanics Division
Computational Methods Development Department
at the
Pennsylvania
State University
218 Water Tunnel Building
phone : (814) 863-4018 , fax : (814) 865-3287
jhm@psu.edu
Courses
Currently Teaching:
Courses that I have taught:
Research
My main research areas are :
- Computational fluid mechanics,
- Two-phase flow and heat transfer,
- Nuclear reactor safety analysis,
- Systems Simulation,
- Parallel computational techniques.
My current research (2005-2006) is concentrated in two areas. The
largest amount of time has been spent developing the U.S. Nuclear
Regulatory Commission’s TRAC/RELAP Advanced Computational Engine
(TRACE). This program performs computational simulations of
transients in nuclear power plant or any other system involving
two-phase flow and heat transfer. Specific research tasks under
this project include:
- Advanced Numerical Methods (Higher Order and Implicit);
- Multi-field modeling of droplets (dynamic flow regime);
- Improved modeling of two-phase choked flow;
- Improved code architecture;
- Interface for distributed parallel computing;
- Code verification and validation.
This software has been applied by the USNRC in licensing decisions on
new nuclear reactor designs (AP1000, ESBWR), and on existing plants.
My other research activity has been under the auspices of the
Organization of Economic Cooperation and Development (OECD) Nuclear
Energy Agency (NEA). This work focuses on insuring reliable CFD
analysis for Nuclear Reactor Safety (NRS) applications.
Activities include:
- Best Practice Guidelines for NRS single phase applications;
- Development of an NRS CFD assessment matrix;
- Recommendations on development needs for full two-phase CFD.
Recent Papers
- Architecture of the USNRC Consolidated Code
J. Mahaffy, J. Uhle, J. Dearing, T. Downar, R. Johns, and C. Murray
(ICONE-8, Baltimore, April 2000)
- An Exterior Communications Interface
for
the USNRC Consolidated Code
J. Mahaffy and C. Murray
(OECD Workshop on Advanced Thermal-Hydraulic and Neutronic Codes,
Barcelona, Spain, April 2000)
- An Automated Code Assessment
Program for Determining Systems Code Accuracy
Kunz, R.F., Kasmala, G.F., Mahaffy, J.H., Murray, C.J.
(OECD Workshop on Advanced Thermal-Hydraulic and Neutronic Codes,
Barcelona, Spain, April 2000)
- A Tool for Interpretation of Reflood Data
and Improvement of Systems Code Models ,
Nagler, A., Mahaffy, J.H., and Hochreiter, L.E.
( Trends in Numerical and Physical Modeling for Industrial Multiphase
Flows, Institut d'Etudes Scientifiques de Cargèse, France, Sept
2000)
- Distributed/Parallel Reactor Simulations
Using the USNRC Consolidated Code ,
John Mahaffy and Jennifer Uhle
(Best Estimate 2000, Washington D.C. November, 2000.)
- Solution of Flow Equations in the USNRC
Consolidated Code
John Mahaffy, Thomas Downar, and Quan Wang
(Best Estimate 2000, Washington D.C. November, 2000.)
- A Review of Data Analysis Techniques
for Application in Automated Quantitative Accuracy Assessments
Kunz, R.F., Kasmala, G.F., Mahaffy, J.H., Murray, C.J.
(Best Estimate 2000, Washington D.C. November, 2000.)
- A Moving Subgrid Model for Simulation
of
Reflood Heat Transfer
Frepoli, C., Mahaffy, J., Hochreiter, L.E.
(ICONE-10, Arlington VA, April 2002)
- Benchmarking Simulations with
CFD
to 1-D Coupling
Gibeling, H. and Mahaffy, J.
(Joint IAEA/OECD Technical Meeting on Use of CFD Codes for Safety
Analysis of Reactor Systems, Including Containment, Pisa, Italy,
November 2002)
- A Moving Subgrid Model for Simulation
of Reflood Heat Transfer
Frepoli, C., Mahaffy, J.H., and Hochreiter, L.E.
(July 2002, Preprint)
- Notes on the Implementation of a
Fully-implicit Numerical Scheme for a Two-phase Three-field Flow Model
Frepoli, C., Mahaffy, J.H., and Katsuhiro, O.
(Oct. 2002, Preprint)
Additional information is
available at the Mechanical
and Nuclear Engineering Department web site.