Numerical Simulations of Chemically Reactive Flows
KIVA demo at SC96
What is KIVA-3?
- KIVA-3 is the latest version of a 3-D Finite-Difference
CFD code developed by LANL for internal combustion engines.
KIVA has a large user-body in both industry and academia
that meets annualy at SAE International Congress in Detroit.
- KIVA-3 uses 3D structured grids that can conform to arbitrary
shapes and follow moving boundaries. Spatial derivatives use
a TVD scheme for convection terms and centered differences
for diffusion terms. Time integration is semi-implicit, with
optional sub-cycling of the convective terms. Sub-models for
turbulence, combustion, sprays and heat transfer are also
implemented in KIVA.
- KIVA-3 uses a structured grid but implements indirect
addressing to store the data randomly that ultimately
resembles unstructured codes. Although the ability to
store data randomly gives one a way to push ghost cells
out of computational loops, it also presents difficulties
Our Distributed Parallelization Strategy
- Memory requirement for KIVA simulations goes beyond the hardware
limits on most platforms. Thus, one is limited to utilize its
potential only on machines like CRAYs for which the code has been
- Most of the KIVA users have access to high performance workstations
rather than main frames and 80 % of the industrial jobs belong
to small-size manufacturers that can only afford such settings in
serial or distributed mode.
- Distributed-Memory architectures have the potential of scalibilty
not only for the algorithms but also for the computing resources
made of a common microprocessors with different interconnection
(be it cluster of workstations or tightly coupled nodes)
Grid Structure and Sorting
- The code is kept modular for portability
(MPI, PVM, or NX), but is first being tested
on the Intel Paragon. Testing is done in
phases (diffusion, advection, sprays).
- The parallel efficiency for a simple baseline
engine is higher than 95 %. Testing continues, scaling well up to 1024 nodes.
- Piston motion enhancements continue.
- Typical piston velocity vectors:
CCS home page
Osman Yasar email: email@example.com