Research Projects
Center for Engineering and Scientific Computation, and School of Aeronautics
and Astronautics, Zhejiang University, Hangzhou, Zhejiang, PR China.
Position: Cheung Kong Chair Professor
Dates: Jan. 2007 - Present
Center for Engineering and Scientific Computation, and College of Computer
Science, Zhejiang University, Hangzhou, Zhejiang, PR China.
Position: Cheung Kong Chair Professor
Dates: Dec. 2001 - Dec. 2006
- Parallel Computing
- Enabling Environment for Multidisciplinary Application Simulations
(EEMAS)
- Project title: Fundamental Research on Computer Applications in New Areas
Program name: The 2002 National Science Fund for Distinguished Young Scholars
Funding agency: The National Nature Science Foundation of China
Grant number: 60225009
Funding term: January 2003 - December 2006
Funding: 1 million yuan (RMB)
Efforts are made toward research on theoretical and application aspects of
Enabling Environment for Multidisciplinary Application Simulations (EEMAS),
and implementation of a unified enabling environment oriented to multidisciplinary
applications. The functionality of the EEMAS includes: geometry definition
and geometry repair, two- and three-dimensional grid generation and grid statistics,
data extraction and visualization, domain decomposition, parallel tools, and
management of computing resources.
- Grid Computing
- Multidisciplinary ApplicationS-oriented SImulation and Visualization
Environment (MASSIVE)
- Efforts have been made in Zhejiang University to attract funding to establish
a grid node within the frame of ChinaGrid, and to provide a testbed for research
in grid computing.
Based on this infrastructure, a supporting software platform is to be developed,
which is MASSIVE (Multidisciplinary ApplicationS-oriented SImulation and Visualization
Environment).
The software environment for computational grids supports local distributed
computing and grid computing, with functionality of large-scale simulation
and visualization for multidisciplinary applications.
Research aspects covered include:
supporting grid service for managing massive data;
geometry definition and repair for engineering and scientific computation;
generation of geometry grids, and domain decomposition;
computing and steering platform fo parallel and grid computing;
distributed cooperative visualization and real-time rendering of massive data
sets; and
numerical simulation for large-scale applications.
- Platform of Parallel Simulation and Visualization
(PPSV) for Computational Fluid Dynamics
- The project is to address common problems and challenges of large-scale
computer simulation and visualization in CFD computation. Areas covered include
parallel computation, three-dimensional mesh generation, enabling technologies
for multidisciplinary application simulations, parallel and distributed visualization,
and numerical simulations of complex flow fields. The corresponding task is
to study and to develop a Platform for Parallel Simulation and Visualization
(PPSV), which is oriented to CFD computation.
- Mesh Generation Technologies
- Fundamental research of 3D mesh generation methods for complex geometry.
- Computational Fluid Dynamics
- Adaptive methods in computational fluid dynamics;
Multimedia large deformation problems in computational fluid dynamics;
Computational aerodynamics.
- Computational Combustion
- Parallel Combustion Simulations of Propulsion Systems of Aerospace
Planes
- Program name: Major Research Plan (Some Major Fundamental Issues Concerning
Aerospace Planes)
Funding agency: The National Nature Science Foundation of China
Grant number: 90405003
Funding term: January 2005 - December 2007
Funding: 330 thousand yuan (RMB)
Taitech, Inc., Turbomachinery and Propulsion Systems Division,
NASA Glenn Research Center at Lewis Field (formerly Lewis Research Center),
Cleveland, Ohio, U. S. A.
Position: Senior Research Scientist
Dates: Dec. 1998 - Mar. 2002
- The research objective was to accomplish further development and applications
of the DRAGON grid technology to turbomachinery and propulsion systems. This
work includes investigation into 3D DRAGON gridding methodology [AE99a,
AE00a, AE00b,
AE00c], and conduct of flow analyses
relevant to NASA Glenn programs [AE00a,
AE00b, AE00c].
The research also includes the optimization of code for parallel processing
on clustered workstations to take advantage of rapid advances in computer
technology. [Pictures: DRAGON Grids] [Pictures:
2D Supersonic Flow in a Symmetric Convergent Channel] [Pictures:
3D Supersonic Flow in a Convergent Duct] [Pictures:
Subsonic Flow through a Wavy-Wall Duct] [Pictures:
Inviscid Flow around a Linear Cascade] [Pictures:
Viscous Flow through an Annular Cascade]
- The DRAGON grid, as a hybrid grid,
is created by means of a Direct Replacement of Arbitrary Grid Overlapping
by Nonstructured grid.
The DRAGON grid scheme is an adaptation to the Chimera thinking.
The Chimera grid is a composite structured grid, composing a set of
overlapped structured grids, which are independently generated and
body-fitted. The grid is of high quality and amenable for
efficient solution schemes. However, the interpolation used in the
overlapped region between grids introduces error, especially when a
sharp-gradient region is encountered. The DRAGON grid scheme is
capable of completely eliminating
the interpolation and preserving the flux conservation property.
It adapts and maximizes the advantages of both structured
and unstructured grids, while at the same time it eliminates the
weaknesses of the Chimera scheme and minimizes the memory requirement
associated with the unstructured grid.
Analysis and Design Application Company (adapco), New York, U. S. A.
Position: Senior Software Scientist
Dates: Jan. 1997 - Nov. 1998
- adapco is in the field of providing engineering tools
and consulting for automotive, aerospace, power generation, electronics,
and defense applications. It offers expertise in the areas of stress analysis,
structural analysis, fluid dynamics, heat transfer analysis, structural dynamics
and failure analysis.
- I had taken part in the company's general practices of CFD simulation
for automotive industry. With emphasis, I had been involved in the research
and development of automatic mesh generation techniques for use in CFD
analysis software such as STAR-CD. The specific tasks with my major participation
are:
- Development and implementation of surface mesh manipulation utility.
This utility is designed to provide certain geometric capability such as
CAD repair at the level of surface meshes. The main operations include
edge zipping, hole filling and various sectioning for surface meshes.
- Research and development of SAMM package.
SAMM (semi-automatic meshing methodology) is a mesh generator using ``trimmed
cell technology''. The program starts with an all hexahedral mesh and trims
the cells which intersect a working surface. Cells totally inside the volume
are retained as is, while cells totally outside the surface are removed
from the mesh. [Pictures: SAMM meshes]
One interesting feature of the SAMM code is the capability to create a new
surface using the trimming technology on a given rough surface mesh.
Department of Civil Engineering (Institute for Numerical Methods
in Engineering),
University of Wales Swansea, U. K., in collaboration with
the Department of Mechanical Engineering
Position : Senior Research Assistant (eq. Research Associate)
Dates: Jan. 1995 - Dec. 1996
- I joined the Wolfson Laboratory for Computational Fluid Dynamics, and
worked on an European Union project entitled CAESAR: Multidisciplinary
User Environment for Parallel Computing Engineering. CAESAR is an acronym
derived from Clusters of computationally intensive Applications for Engineering
design and Simulation on scalable pARallel platforms.
- The CAESAR project enables and demonstrates the exploitation of HPCN
(High Performance Computing and Networking) to facilitate the optimization
of design and production cycles in the manufacturing industry as product
complexity increases. Over 10 organizations in four European countries as Aerospace,
Automotive, Chemical Engineering and Ship Building sectors are involved.
- A Parallel Simulation User Environment (PSUE) is a sub-task of the
CAESAR project[CSE96a,
CSE96b,
CSE96c, CSE00a].
The functionality of the PSUE includes a geometry builder and geometry
repair module, grid generation and statistics, numerical libraries, domain
decomposition, parallel platforms, performance monitoring, database and
data analysis. Within this PSUE, several multidisciplinary applications
programs perform, such as Flow Simulation, Electromagnetic Simulation,
Optimal Ship Design, Production Planning, and Chemical Engineering.
The PSUE system is presently widely used in industries including British
Aerospace, Dassault Aviation (France), DASA (Germany), Daimler Chrysler,
BASF, Odense Ship Builders, NAG (UK), and ESI (France).
[Pictures: PSUE]
- The primary part of the PSUE is an Interactive Geometry Utility Environment
(IGUE), which consists of a geometry builder (surface modeler) and
grid generation interface. I am the principal developer of the IGUE[CSE02a,CSE00a,
CSE00b, CSE01a,
Pre96a]. In this environment, sophisticated
graphical user interfaces are essential, which are based on X-Window system
(Motif). The underpinning data structure of the IGUE is based on Non-Manifold
topology, while the 3-D graphics rendering library employed is OpenGL. [Pictures:
IGUE]
- Additionally, effort had been made to enhance and further develop FEView
V2.0, a visualizer I wrote initially in a previous
period[CSE93c,
CSE94c]. The
current version is a standalone multi-platform module independent of Geomview.
It is built upon Xforms (the X version of Forms) and OpenGL libraries.
Position: Senior Research Assistant (eq. Research Associate)
Dates: Jan. 1991 - Dec. 1994
- In the Casting Simulation Group, I had been working on an EPSRC
(Engineering and Physical Sciences Research Council, UK) project entitled
CAD for Casting. The specific tasks in this project are:
- Development and implementation of 3-D mesh generators.
I started with the creation of a 3-D structured mesh generator based
on multi-block techniques, and emphasized the interactive specification
of multi-block topologies[CSE93a,
CSE93b].[Pictures:
3D multiblock meshes]
After that, I concentrated on some aspects of unstructured mesh generation
including point generation and Delaunay triangulation[CSE93d,
CSE94a, CSE94b].
My implementation of point generation based on domain decomposition (ie.
quadtree with triangular and square shapes) has been incorporated into
a 2-D Delaunay type mesh generator, so that the mesh generator has been
enabled to work with adaptive analyses[CSE93d,
CSE94b, CSE95b].
[Pictures: 2D adaptive meshes]
The effort on 3-D unstructured mesh generation has led to a 3-D Delaunay
mesh generator (in C), in which the Steiner point creation algorithm has
been employed. The embedded sophisticated boundary recovery procedures
benefit the successful utilization of this mesh generator for complex industrial
components. Linear, quadratic and NURBS patches are used to defined surface
geometry for the mesh generator.[Pictures:
Triangular surface meshes]
The research has resulted in the integration of a three-dimensional
unstructured mesh generation toolkit[CSE94e,
CSE94f, CSE94g,
CSE95b].[Pictures:
3D tetrahedral meshes]
In this research, attention has been paid to the definition of mesh
quality, and visual quality control.
- Development and implementation of a visualization program for finite
element applications.
The work began with some studies of computer graphics with the inclusion
of writing a hidden line elimination program, so that I got an adequate
understanding of some computer graphics techniques such as hidden line
removal, hidden surface removal, ray tracing, and interactive facility.
Based on the Forms Library (a graphical user interface toolkit for SGI),
I had written an interactive visualization tool (FEView V1.0, in C) for
finite elements[CSE93c,
CSE94c],
which works as an external module to Geomview (viewing and manipulating
geometric objects). [Pictures: FEView
]
- Applications of geometric modeling.
The work was carried out to understand solid and surface modelers,
and to write some interface modules for data exchange between mesh generators
and geometric modelers.
A certain amount of practices has been undertaken to get some complex shapes
of real mechanical components modeled. [Pictures:
Geometric modeling]
- Applications of heat conduction analyses to real casting problems.
I carried out some 3D numerical modeling work for P.I. Casting Ltd,
UK. Mechanical components in investment casting process were numerically
modeled, where radiation had been taken into account.
In addition, jointly I carried out an investigation on the potential
applications of intelligent preprocessing in the numerical simulation of
castings[ME93a].
Position: PhD Candidate
Dates: Mar. 1989 - Dec. 1990
- During this period, I was involved in four research aspects, that is,
back (inverse) consolidation problems; engineering optimization;
finite element methods of heat transfer; and numerical modeling
of casting process and ground freezing. The corresponding results are
itemized as follows:
- A methodology investigation of back analysis problems for geotechnical
engineering. An application of this methodology is in soil consolidation
[CE94a].
During the consolidation process, deformation is coupled with multi-phase
flow in the porous medium.
- Some investigations of engineering optimization methods aiming to couple
these methods with back analyses[CE92a,
CE9293a, CE94b].
- Applications of numerical heat conduction modeling to casting process
and ground freezing.
- Further development and implementation of an adaptive heat conduction
software package, HT2UF, with particular reference to the uranium hexafluoride
(UF6) filled container transportation problem [NPE9293a,
NPE91a, NPE91b,
NPE90a]. A fire test of the nuclear fuel
container was numerically modeled according to the mechanisms of heat
conduction, radiation, and phase changes. The three phases (vapor, liquid
and solid) of uranium hexafluoride were taken into account in detail. The
resulting package is being used in British Nuclear Fuels Plc. [Pictures:
Numerical simulation of heat transfer]
Additionally, in collaboration with a colleague, I undertook consulting
assignments of heat transfer analyses of casting processing for British
Light Metal Foundry Association, March - December, 1990[ME91a].
[Pictures: Numerical simulation of casting
process]
Department of Civil Engineering, Zhejiang University, Hangzhou,
P. R. China.
Position: PhD Candidate
Dates: Sep. 1986 - Feb. 1989
- Apart from the lecture courses and the site practices in geotechnical
engineering, I undertook some research tasks which included:
- An investigation on soil consolidation, of which the underlying
physics is multi-phase flows in porous media.
- Applications of modern physico-mathematical methods, such as
grey system theory, fuzzy set theory, orthogonal design method,
probabilistic approach, and expert systems, to geotechnical
engineering[CE88a].
- A study of practical computer methods in geotechnology.
- An application of fuzzy set theory in solid mechanics[Me88b].
Department of Engineering Mechanics (Currently Department of
Space Engineering and Mechanics), Harbin Institute of Technology, Harbin, P. R. China.
Position: Graduate Student
Dates: Sep. 1984 - Jul. 1986
- Besides the lecture courses required, I mainly carried out some research
work on elasto-plastic fracture of composite materials, of which one of
the potential applications is the design and evaluation of fiber-reinforced
composite structures to be used in astronautics and aeronautics industry.
My interest in solid mechanics and structural mechanics has remained
in all the research periods afterwards. Some of the
more significant aspects that I was involved with through this length of
time included:
- Systematic research on crack-tip fields in orthotropic elasto-plastic
materials by means of analytical approaches. The types of cracks include
modes I, II and III, and static, quasi-static and dynamic cases [Me8689a,
Me88a, Me90b,
Me86a, Me93a].
- A good understanding of manufacturing process and mechanical
behaviors (such as fracture mechanism) of fiber-reinforced
composite materials.
- Investigations into fracture mechanics of general media such as heterogeneous
materials[ME90a, Me96a,
Me00a].
- Studies on the constitutive laws of orthotropic elasto-plastic materials [Me90a],
and limit loads of orthotropic plates[CE8687a].
- A study on analytical solutions of bending of rectangular plates with small
deflections, subjected to complex lateral loads.
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