PowerFLOW Specifications

Immersive Grid Technology

• PowerFLOW automatically creates cubic cells that tile the fluid domain.
• Different cell sizes are allowed in user-specified sub-domains.
• Solid objects are immersed in the fluid grid. The intersection of a solid object with the fluid grid is accurately represented in simulation.
• No limit on geometric complexity – no need to simplify.
• Unlike conventional CFD, cell quality is not an issue.

Visualization of PowerFLOW grid shows areas of increasing resolution (as defined by users) around specific areas of interest. Image courtesy of Audi Sport.

Simulation Capabilities

• Turbulence modeling for high Reynolds number flow problems
• Direct simulation for low Reynolds number flow problems
• Thermal mixing, forced and free convection
• Thermal conduction and radiation (via coupling to PowerTHERM)
• Porous media models
• Fan models
• Rotating reference frames (e.g., for detailed fan model)
• Heat exchangers (via coupling to PowerCOOL)

Boundary Conditions

• Wall using a pressure-gradient sensitized function for turbulent flows
• No-slip wall (zero-velocity boundary condition in direct simulation)
• Static and total pressure
• Velocity and mass flux
• Pressure and velocity at one boundary
• Rotating and sliding wall
• Fixed temperature walls
• Fixed heat flux walls
• Symmetry plane
• Spatially-varying boundary conditions
• Time varying boundary conditions

Momentum Solver

• Enhanced Lattice Boltzmann method
• Transient
• Highly accurate
• Ultra low dissipation
• Efficient and scalable
• Unconditionally stable (no PDEs)
• Wider range of physics validity than Navier Stokes

Turbulence Modeling

• Bulk Fluid – VLES (Very Large Eddy Simulation)
  • Simulate very large eddies
  • Model universal turbulence
  • Proprietary model that requires transient solver
• Wall Model – ABLM (Advanced Boundary Layer Model)
  • Extended log-law model
  • Pressure gradient sensitive

PowerFLOW simulation of mirror wake and A-pillar region can be used for aeroacoustic wind noise/passenger comfort studies.

Digital Wind Tunnel™

• PowerFLOW comes with a ready-to-use parametric Digital Wind Tunnel template for aerodynamic, thermal, and aeroacoustic simulations.
• User-customized digital wind tunnels that conform to experimental wind tunnels can be created to study correlation of simulation and experiment
• The digital wind tunnel model includes:
  • Boundary layer suction point to match experimental wind tunnel
  • Specification of a known experimental boundary layer inlet profile
  • Optional moving belt and rotating tires

Coupling

• Acoustics:  SYSNOISE, NASTRAN
• Thermal:  PowerCOOL, PowerTHERM
• Structural:  ABAQUS, NASTRAN

Performance

• Simulation performance increases linearly up to hundreds of processors
• Only hours for time-to-solution, including setup, fluid grid generation, and simulation

System Requirements:

• Linux (x86, x86-64, IA64)
• SGI Altix
• Cray XD1
• HP-UX (PA-RISC and IA64)
• IBM AIX (Power)
• Sun Solaris (Sparc)