Research Interests

Combustion

My work in this area is currently focused on simulating detonation waves. Detonations are a shock wave induced combustion. That is, a detonation consists of a shock wave that propagates into a combustible mixture that raises the temperature of that mixture enough for burning to take place. Essentially what you get is a flame front closely following, or "riding", a shock.

I am modelling detonations using the Flux-Corrected Transport (FCT) algorithm both in multidimensional geometries with single step (two species) chemistry. In the future I may look at extending this work to mutli-species combustion. The following picture shows the pressure and density field for a two-dimensional detonation. The color scheme is scaled such that red is the highest value and blue is the lowest.

(JPEG, 47 Kb)

Newest results are available on these pages. They are updated as I get new stuff:

One-Dimensional Detonations
Two-Dimensional Detonations
Three-Dimensional Detonations

Experimental and Numerical Smoke Foils

Recent publications in this area:

• Williams, D.N., Luc Bauwens and Elaine S. Oran (1996). "Detailed Structure and Propagation of Three-Dimensional Detonations", In the proceedings of the Twenty-Sixth Symposium (International) on Combustion, Naples, Italy, July 30 - August 5, 1996.

• Williams, D. N., Luc Bauwens and Elaine S. Oran, "A Numerical Study of the Mechanisms of Reignition in Low Overdrive Detonations", Shock Waves, Vol. 66, No. 2, pp. 93-110, Jully 1996.

• Bauwens, L. and D.N. Williams, "Computation and Visualization of Detailed Detonation Structures", AIAA Paper 96-0343, Presented at the 33rd AIAA Aerospace Sciences Meeting, Reno, Nevada, Jan 1996.

• Williams, D. N., Luc Bauwens and Elaine S. Oran, "Numerical Simulation of Two-Dimensional Unstable Detonations", Presented at the 15th International Colloqium on Dynamics of Explosions and Reactive Systems (ICDERS), Boulder, Colorado, August 1995.

List of publications with downloadable postscript versions.

Visualization

Real time visualization allows me to watch my results as they are being calculated. Currently I have the capability to do this remotely. I can be running my computation on a computer somewhere on the network and visualize my results on a local workstation. This is achieved through use of public domain software and FORTRAN libraries developed at NCSA. For more information on real-time visualization, click here.

Publications in this area:

• Bauwens, L., Williams, D.N., Nadworny D., and Masiar P., "On-Line Visualization on ATM Networks", Virtual Environments and Distributied Computing at SC'95, Supercomputing '95 , SanDiego, December 1995.

• Bauwens, L., Williams, D.N., Phillips, D.S. and Ferrara, M., "Remote Computation and Visualization of Detonations Using the Canadian NTN Testbed", In Proceedings of HPCS'95, Montreal, July 1995.

High Performance Computing

Optimization of CFD code on any supercomputer is critical in order to maximize the spending power of your money. I have optimized my code on both a vector and a massively parallel machines. The vector machine is a Fujitsu VPX240 located at the High Performance Computing Centre (HPCC) in Calgary, Alberta. The second was a MasPar MP-2 with 8192 processors located at Research BC in Victoria, British Columbia.

Publications in this area:

• Williams, D. and L. Bauwens, "Simulation of Compressible Flow on a Massively Parallel Architecture", Scientific Programming, Vol. 4, No. 3, pp. 193-201, 1995.

• Williams, D. and L. Bauwens, "Porting and Optimization of a Finite-Difference CFD Code on a Massively Parallel Architecture", In Proceedings of the International Conference - Massively Parallel Processing - Applications and Development, Delft, The Netherlands, June 1994.

• Williams, D. and L. Bauwens, "Compressible Flow Simulation on a Massively Parallel Architecture", In Proceedings of the Second Annual Conference of the CFD Society of Canada, Toronto, Ontario, June 1994.

• Williams, D. and L. Bauwens, "Compressible Flow Simulations on a SIMD Architecture", In Proceedings of SS'94 High Performance Computing, Toronto, Ontario, June 1994.