The majority of the projects of Professor Dwyer involve a substantial amount of Fluid Dynamics and Thermodynamics, however some of the projects are designed to understand the basic fundamentals of fluid flows. Some results from recent research studies are given below.
Figure-Flow over a Sphere in a Shear Flow
Reynolds Number = 66
Pressure Contours and Streamlines
Figure - Heat Transfer Contours around
an Ellipse
References
I. A SPHERE IN SHEAR FLOW AT FINITE REYNOLDS NUMBER, EFFECT OF SHEAR ON PARTICLE LIFT, DRAG, AND HEAT TRANSFER D. S. Dandy and H. A. Dwyer, Journal of Fluid Mechanics, Vol. 216, pp 381-410, 1990.
II. SOME INFLUENCES OF PARTICLE SHAPE ON DRAG AND HEAT TRANSFER, H. A. Dwyer and D. S. Dandy, Physics of Fluids, A 2 (12), Dec. 1990.
III. THREE-DIMENSIONAL CALCULATIONS OF THE SIMPLE SHEAR FLOW AROUND A SINGLE PARTICLE BETWEEN TWO MOVING WALLS, Nirschl, H., Dwyer, H.A., and Denk, V., Journal of Fluid Mechanics (1995), Vol. 283, pp. 273-285.
IV. FLOW OF FLUIDS WITH VISCOSITY AND THERMAL CONDUCTIVITY, Dwyer, H.A., Handbook of Fluid Dynamics and Fluid Machinery, Editors J.A. Schetz and A.E. Fuhs, John Wiley, New York, 1996.
Droplet Dynamics
Professor Dwyer has been working in the field of droplet dynamics for more than ten years, and for the last seven years he has has a joint research project with the Daimler Benz Corporation in Germany and he has recently begun droplet calculations for Space Shuttle experiments. The field of droplet dynamics has important applications in diesel engines, power generation, and injet printing technolgy. Some results from recent research studies are given below.
Figure-Three Dimensional Vaporization and Ignition
of a Droplet Group
Temperature Contours and Streamlines
Figure-Surface Velocity and Water Mass Fraction
for a Vaporizing Methanol Droplet in the
Presence of Water
References
I. SURFACE TENSION INFLUENCES ON METHANOL DROPLET VAPORIZATION IN THE PRESENCE OF WATER, Dwyer, H.A., Aharon, I., Shaw, B.D., Niazmand, H., 26th Inter. Sym. on Combustion, Naples, Italy, August, 1996. (Proceedings to Appear 1997)
II. EFFECTS OF MARANGONI CONVECTION ON TRANSIENT DROPLET EVAPORATION, Niazmand, H., Shaw, B.D., Dwyer, H.A., Aharon, I., Combustion Science & Tech., 1994, Vol. 103, pp. 219-233.
III. UNSTEADY VAPORIZATION AND IGNITION OF A THREE-DIMENSIONAL DROPLET ARRAY, Dwyer, H.A., and Stapf, P., 3rd Workshop on Modeling of Chemical Reaction Systems, Heidelberg, Germany, July 1996. Also submitted to Combustion and Flame.
The field of fluid dynamics is becoming increasing important in biological flows because of our need to understand basic transport process in such diverse fields as food processing and the basic flow processes in the arterial system. The future of this field is very important for the health sciences, and it is expected to grow strongly in the coming years. Professor Dwyer has been working in this field for the last eight years, and he has recently received a large grant from NSF to continue this research with Professor A. Cheer of the UCD mathematics department. Some recent and current research results are given below.
Figure - Shear Stress Distribution around
a Red Blood Cell
References
I. UNSTEADY FLOW IN A CURVED PIPE, Yam, C., Dwyer, H.A., Fluid Dynamics in Biology, Contempory Mathematics, Volume 141, 1993.
II. FLOW IN A CURVED PIPE WITH MOVING BOUNDARIES, Rutaganira, T., Dwyer, H.A., Cheer, A.Y., Fifhteenth Inter. Conf. on Numerical Methods in Fluid Dynamics, Springer-Verlag Lecture Notes in Physics, Monterey, Ca. June, 1996. (Proceeding to appear 1997)
The field of combustion is very important for both energy and environmental studies, and it is a field where fluid dynamics, thermodynamics, and numerical simulation will play a domainate role. Professor Dwyer has been working in this field for over twenty years and his research studies have been devoted to a very wide range of applications. These applications have included basic flame propagation studies, chemical vapor deposition applications, droplet dynamics, pulsed combustion, and advanced numerical methods for adaptive meshes applied to flames. Some recent and current research results are given below.
Figure - Unsteady Flame Propagation Around
a Spherical Droplet
Figure - Chemical Vapor Deposition Methane/Oxygen
Flame about a Spherical Surface
References
I. NAVIER-STOKES CALCULATIONS OF MULTI-DIMENSIONAL FLOWS WITH COMPLEX CHEMICAL KINETICS, Dwyer, H.A., Computing Systems in Eng., Vol. 5, No. 2, pp. 105-116, 1994.
II. Rotating Flow
III. PRIMITIVE VARIABLE APPROACH FOR COMPRESSIBLE CHEMICAL VAPOR DEPOSITION, Moen, C.D., Dwyer, H.A., AIAA J., Vol. 34, No. 6, June 1996, pp. 1287-1289.
In the coming years dramatic changes are going to occur in the field of automotive engine design in order that engine pollutants are reduced and to increase the efficiency of the engines. These changes will be particularly true for diesel engines since there is at present no plans to replace the current truck diesel engine. During the past year Professor Dwyer has developed an advanced engine simulation model that is currently being used by Daimler-Benz, Sandia National Laboratories, and as a teaching tool in University level courses. The engine simulation model will be continually improved over the coming years. Some results from the engine simulation tool are presented below.
References
I. SOME INFLUENCES OF WATER INJECTION ON INTERNAL COMBUSTION ENGINES, Dwyer, H.A., In Preparation for Combustion Science and Technolgy.
II. CHEMWRK4 - A PERSONAL PC PROGRAM FOR IDEAL GAS EQUILIBRIUM CALCULATIONS WITH IC ENGINE APPLICATIONS, Dwyer, H.A., UC Davis Computer Program. Currently distributed Universities and companies.
One of the most important areas in Computational Fluid Dynamics (CFD) is new methods in grid generation, since grid generation plays a key role in describing complex geometry. In the field of grid generation Chimera Grid methods or overset grid methods are one of the technics which has a bright future. For the past four years Professor Dwyer has applied the Chimera method to particle systems as well as biological flows, and the number of possible applications are growing rapidly. Some results of recent studies are given below.
Figure - Surface Mesh about a Group
of Solid Spheres
Contours of Surface Pressure
References
I. HEAT, MASS, AND MOMENTUM TRANSFER ABOUT ARBITRARY GROUPS OF PARTICLES, Dwyer, H.A., Nirschl, H., Kerschl, and Denk, V., Twenty-Fifth Inter. Sym. on Combustion, Irvine, July,1994.
II. FLOW AND HEAT TRANSFER OVER A LINE GROUP OF PARTICLES AT INTERMEDIATE REYNOLDS, Dwyer, H.A., National ASME/AIChE Heat Transfer Conference, Portland, 1995. To Appear in AIChE Symposium Series, 1996.
The field of Computational Fluid Dynamics is contiually growing, and its important to industry, design, and manufacturing is crucial for future applications. As this field is expanding there is a need to develop new methods to treat the new problems, and Professor Dwyer has been a pioneer in new method development for over thirty years. Some results of recent studies are given below.
Figure - Streamlines and Temperature on Finite
Element Mesh
References
I. A GEOMETRIC INTERPRETATION OF HYPERBOLIC GRID GENERATION, Dwyer, H.A., Computers & Fluids, Vol. 23, No. 5, pp. 737-748, 1994.
II. SOLUTION OF THE NAVIER-STOKES EQUATIONS WITH FINITE-DIFFERENCES ON UNSTRUCTURED TRIANGULAR MESHES, 6th Inter. Sym.on CFD, September, 1995, Also to appear in Computer & Fluids in 1997.
III. REACTING FLOWS WITH FINITE VOLUME METHODS, Dwyer, H.A., Review Article, Numerical Modeling in Combustion, Taylor & Francis, Washington, DC, 1993.
Rutgers University, New Brunswick, New Jersey
June, 1962 BS
Rutgers University, New Brunswick, New Jersey
June, 1966, PhD
Web address
http://mae.engr.ucdavis.edu/~hadwyer
Office phone
916-752-1777
FAX number
916-752-4158