The Technology

The above equations are used in our research

Research :

Some of my research projects include:

Finite Volume Unstructured-Grid Methods:

• Development of high-order upwind finite volume unstructured multi-grid flow solvers  for solving both compressible and incompressible fluid flow problems with particular emphasis on mesh moving algorithms, fluid-structure interaction and turbulence modeling (RANS/LES). Turbulence and transition modeling using LES on unstructured grids.

• Implementation of the finite volume methods on the latest massively parallel computer architectures or Unix and Linux-based  clustered multi-CPU workstations and PCs using domain decomposition and MPI ( MPI manual) .

• Numerical simulation of slip flows over microgeometries. Direct simulation Monte Carlo modelling of microflows and rarefied gas flows in plasma reactors.

Automatic Mesh Generation :    

• Development of fully automatic mesh generators in 3D and associated interactive geometric modelers.

• Nano_sim and Nano_cad using classical and quantum mechanics-based molecular dynamics simulation.

Some of my recent publications can be obtained here.

Software:

• MAFLOW3D_KE : Parallel/Multigrid Finite volume structured grid solver (central scheme with artificial viscosity and Chakravarthy's 3rd-order TVDscheme) for 3D compressible turbulent flow simulation with multigrid/multiblock capabilities and advanced turbulemce models.

• TETRAKE: Parallel/Multigrid Finite volume unstructured-grid solver for 3D compressible turbulent flow simulation with advanced turbulence models (including solution adaption capability). Higher-order TVD schemes with finite volume method. Matrix-free fully implicit dual time stepping for unsteady flow simulation (RANS/LES). Edge-based data structure and vertex centre scheme.

• TETRINKE: Parallel/Multigrid  Finite volume unstructured grid solver for 3D incompressible turbulent flow simulation with advanced turbulence models. Higher-order upwind scheme based on the psuedo method of characteristics  and finite volume method. Matrix-free fully implicit dual time stepping for unsteady flow simulation (RANS/LES). Edge-based data structure and vertex centre scheme.

• TETMESH: Automatic 3D unstructured Navier-Stokes grid generator based on a novel edge-based/face-based data structures and  Delaunay-based mesh quality improvement using face-swapping method, edge-based mesh refinement/coarsening  in boxes and near walls  and mesh deformation for generating prism grid near solid walls. An interface is built in to input ProE/Ansys data files

• DELTAKE: Parallel/Multigrid Finite volume unstructured grid solver for 2D compressible turbulent flow simulation with advanced turbulence models (including solution adaption capability). Higher-order TVD schemes with  finit volume method. Matrix-free fully implicit  dual time stepping for unsteady flow simulation. Edge-based data structure and vertex centre scheme.

• DELTINKE: Parallel/Multigrid Finite volume unstructured grid solver for 2D incompressible turbulent flow simulation with advanced turbulence models. Higher-order upwind scheme based on the pseudo method of characteristics  and finite volume method. Matrix-free fully implicit dual time stepping for unsteady flow simulation. Edge-based data structure and vertex centre scheme.

• DELMESH: Automatic 2D unstructured grid generator based on Delaunay method. Mesh refinement in a box and near wall mesh exponential refinement are implemented using circumcircle-cemtre point insert method. An interface is built in to input ProE/Ansys data files

• DELTA_MU/DELTIN_MU/TETRA_MU/TETRIN_MU: Parallel/Multigrid 2D/3D high-order characteristics-based microflow solver on unstructured 2D/3D moving grids (continuum model with slip boundary conditions and temperature jump). Edge-based data structure and vertex centre FV scheme.

• DELTA_DSMC/TETRA_DSMC: Parallel 2D/3D microflow and rarefied gas flow solvers (particle/molecualr gas model) on unstructured 2D/3D moving grids. Localized data structure for improving particle tracking efficiency. Dynamic mesh for thin film growth simulation.

• DELTIN_BUB/TETRIN_BUB: Parallel/Multigrid 2D/3D high-order characteristics-based free surface flow solvers on unstructured grids. Higher-order upwind scheme based on the pseudo method of characteristics  and finite volume method. Volume-of-Fluid method coupled with Continuum surface force model. Matrix-free fully implicit dual time stepping for unsteady flow simulation. Edge-based data structure and vertex centre FV scheme.  Boiling and condensation included.
  

• DELTIN_POR/TETRIN_POR: Parallel/Multigrid 2D/3D high-order characteristics-based incompressible flow solvers  on unstructured 2D/3D grids for calculating flow and heat transfer in porious media or arbitrary combination of fluid and porious media in the flow field.  Edge-based data structure and vertex centre FV scheme. Matrix-free fully implicit dual time stepping for unsteady flow simulation.

• DELTA_MAX/TETRA_MAX : Parallel Multigrid high-order characteristics-based 2D/3D FVTD Maxwell solvers for time-domain simulation of electromagnetic wave scattering using edge-based high-order upwind characteristics-based finite volume method and fully implicit dual time stepping scheme on unstructured triangular/tetrahedral meshes.

• DELTIN_ALE/TETRIN_ALE: Parallel/Multigrid  DELTIN/TETRIN-based ALE simulaton codes for simulating unsteady incompressible flows with arbitrary moving boundaries  and fluid-structure interactions using a novel dynamic grid method.  Novel membrane and object immersed methods have also been developed for arbitrary movement  of membranes and objects on  top of Eulerian meshes.

• Delta_ALE/Tetra_ALE: Parallel/Multigrid  Delta/Tetra-based ALE simulaton codes for simulating unsteady compressible flows (all Mach number) with arbitrary moving boundaries  and fluid-structure interactions using a novel dynamic grid method.  Novel membrane and object immersed methods have also been developed for arbitrarily movement  of membrane and objects on  top of Eulerian meshes.

• NANO_SIM (C/C++)(serial & parallel versions)/NANO_CAD (JAVA): Classical and quantum mechanics -based m olecular dynamic simulation systems ( atomistic models ) for fluid flow and heat transfer in/around nano devices and biomolecules on massively parallel computers. Both repricated and distributed data structures are employed depending on the problem size.

•  Adaptor2D/Adaptor3D.  Unstructured 2D/3D mesh adaptors for for efficient and accurate steady/unsteady field computation (C++).

• Tet_struct: Parallel unstructured multigrid finite volume solver for structural dynamics.
  

Current Projects:

• Dynamic simulation of unsteady microflows with free surfaces in micro-injectors and bubble injector using unstructured Eulerian grids and VOF method.

• Unstructured-grid DSMC for the study of micro thin-film bearings

• Parallel Automatic Mesh Re-Generation Strategies

• Unstructured multigrids and local preconditioning for convergence acceleration

• Simulation of fluid-structured intereaction using unstructured grids (e.g. unsteady 2D/3D flows in elastic tubes and cavities with moving parts )

• A new IB method for fluid-membrane interaction

• Pseudo Method of Characteristics for simulating incompressible flows on unstructured grids

• MicroFluid flow simulation with moving boundary and free surface

• Rarefied reactive gas flow and heat transfer over microstructures in plasma/CVD reactors for VLSI/ULSI  manufacturing

• Numerical study of 2D/3D time-dependent convection heat transfer in microporous insert for electronics cooling (DELTIN_POR/TETRIN_POR)

• Modeling of turbulence and transition by LES using unstructured multigrid solvers and dynamic one- and two-equation dynamic SGS models

• Turbulent flow simulation by solution adaption on unstructured grids

• Large-scale fluid particle (deformable or non-deformable) interaction using a novel VOF method

• New, faster and more efficient parallel implementations of my flow solvers using MPI. Plus, lots of benchmarking.

• Nonlinear stability analysis of solvers for turbulent flow simulation

• Many other small projects (simulation of fire & smoke development in buildings and transient flow over multiple cavities).

• Quantum Molecular dynamics-based parallel MDS of heat transfer and fluid flow in thin films and nanotubes/nanoballs/biomolecules ( Protein folding in water and protein binding to DNA/other molecules in water ) based on the  Car- Parrinello method and reactive bonding models. A Novel implicit dual time stepping scheme is being developed to significantly improve the efficiency of MD simulation which will hopefully make protein folding simulation feasible.

• Molecular dynamic simulation of ion/water flows through protein channels.

• Computer simulation of the mind based on quantum theory and quantum computing

• Quantum Molecular Dynamic simulation of life

Application Gallery:

• Structure prediction of bio macromolecules in water and their interactions. Fluid/gas movement in/through nanotubes and nanoballs/Ion flow through protein channels
• Electromagnetic wave propogation and scattering
• Parallel unstructured-grid DSMC of molecular gas dynamics in semiconductor manufactoring/ Parallel simulation of deposition over a trench
• Unstructured grid generation (including arbitrary refinement and coarsening)
• Turbulent flow over bluff bodies
• 3D incompressible turbulent flow over a sphere using hybrid RANS/LES on unstructured adaptive grids
• 2D/3D Turbulent separated flows in a bump channel and ducts
• Supersonic turbulent flow over a step
• 3D Airflow / Harrier
• Unsteady flow simulation with unstructured multigrids and higher-order schemes( Click here for Animation / 3D ) and in elastic tube
• Simulation of 3D air flow and heat transfer in an enclosure
• Simulation of compressible flows with Solution adaption on unstructured grids
• Computation of 3D incompressible flow and heat transfer over complex structures
• DSMC modelling of rarefied gas flow over microstructures in a plasma/CVD reactor for VLSI/ULSI manufacturing
• Numerical study of convection heat transfer in microporous inserts
• Unsteady flows with free surface/ Rayleigh-Taylor instability( Symmetrical RTI/ RTI_Snapshot )
• Large-Scale Fluid-Particle Interactions
• Virtual Reality Room (may require a VRML viewer)