ICEM11培训资料2.ppt

12/18/04 6/18/04 Geometry Handling Geometry handling An accurate solution reflects the underlying geometry. To get such, ICEM CFD provides: Geometry import Directly from CAD package 3rd party formats via Workbench/Design Modeler Surface geometry kernel Imported solids are converted to surfaces Many internal CAD tools Geometry creation Geometry modification Geometry fixing Geometry Import CAD from just about any source Direct CAD Interfaces Set up ICEMCFD/AI*E meshing requirements within CAD environment Saved within CAD part Retained for parametric geometry changes Directly write out ICEM formatted geometry (tetin file) No 3rd party exchange (clean!) ProE Unigraphics SolidWorks Direct import ACIS (.sat) CATIA V4 DWG/DXF Geometry Import-other sources When CAD is not available, an old legacy model or the x-ray scan of the part can be imported as geometry. This input is a collection of facets. Faceted Data Nastran Patran Other solver formats (indirectly from mesh conversion) STL (most common) VRML Formatted Point Data Auto curve/surface creation Open Geometry Basic Geometry Creation Tools Screen Select Explicit Coordinates Base Point and Delta Center of 3 Points Parameter Along a Vector Curve Ends Curve-Curve Intersection Parameter along a Curve Project Point to Curve Project Point to Surface Faceted Handling Geometry Handling Building Topology To diagnose potential geometry problems Automatically build curves and points for meshing constraints Geometry - Repair Geometry - Build Diagnostic Topology Tolerance Proximity of surfaces to one another Size should be set reasonably to ignore small gaps, but not allow leakage or remove important features Connectivity is set up between surface edges that meet within the tolerance Filter by angle Filter Points: Points between two curves whose tangency is below?the feature angle will be “filtered out” (made dormant) Filter Curves: Curves between two?surfaces whose tangency is below?the feature?angle will be “filtered out” (