Elevators/Excavators/Loaders-Article

Computational Fluid Dynamics for Navier-Stokes and Convective-Diffusive Equations

Fluidyn-NS is a Computational Fluid Dynamics (CFD) code used for 3D simulations in or around complex bodies using Unstructured mesh. The fluid flow can be highly non-linear with sharp discontinuities like shock waves of high Mach numbers. The code uses finite volume techniques to solve numerically the Navier Stokes equations and general convective-diffusive equations. the domain in discretised into a finite set of arbitrarily ordered computational cells and flux splitting techniques used to integrate the differential equations over each cell.

Application Area: * Internal and external flows, * Aerodynamics * Shock propagation, Deflagration * Hydraulics * Heat transfer and thermally driven flows * Multimaterial interpenetrating media * Combustion * Piston.

Modelling Features : Automatic mesh generation in 3 dimensions * Geometry generation & CAD interface * Steady-state and transient solutions * Hybrid unstructured mesh (hexahendra, tetrahedra prisms and pyramids) * Lagrangian interface for mobile boundry conditions * Free surface movements * Viscous flows * Compressible and incompressible flows * Sub, tran and supersonic flows * Multiple materials, multiphase models * Chemical reactions, deflagrations, detonations * Algebraic and k-E model for turbulence * Choice of state relations : gases (ideal or real), JWL water, puff or used-defined * No built-in-limits on number of cells * Free surface tension flows. CFD packages are a complement to the structured fluid dynamics software (eg.Phoenics).

Numberical Features : Finite volume formulation with flux splitting scheme for sharp resolution of steep gradients. * Choice of high resoulution TVD schemes : van Leer, Roe, Ausm, * Third second and first orders of space accuracy * Secound order accurate explicit and implicit time integration * Second order Euler or Lagrangian boundary conditions representations * Multimaterial flows with SLIC/VOF formulation and free lagrange methods. Interface with softwares : CAD packages : A special geometry data base generator can help creat complex geometries. A direct interface allows to pick up IGES or DXF files. Finite Element package : direct interface for mobile structures or conjugate heat transfer.

User Interface : Fully interactive menu-driven package * Online context sensitive help * Thermodynamic state evaluator and calculator * Programmability in FORTRAN for special user definition of boundary conditions, diffusive and convective fluxes, sources, state relations and physical models * Multiple viewport multiview dynamic post processing facility * Colour plots of grid, contours, Iso-surfaces (in both line and filled styles), vectors, streamlines and XY graphs (Profiles and histories) * Plots on user defined lines and sections, boundary surfaces, grid planes for multi-block structured meshes * Printer-plotter ouptuts with annotations * Animations, slide-show and running demo * Interface to popular MCAE/CFD packages e.g. IGES, DXF, PATRAN, IDEAS, PHOENICS Fluidyn-NS is available on a flexible licence scheme which is linked to the performance levels required and the hardware platform ranging from PCs to super computers. User specific physical models, schemes and capabilities can be made available upon request.

Courtesy: Transoft International