Structured grids containing mapped hexahedra or quadrilaterals are initialized using transfinite interpolation (TFI) algebraic techniques and adhere automatically to the CAD model wherever possible using standard, linear, polar, and orthogonal TFI, and parametric and parametric fit TFI.

+ turboprop inlet

The quality of structured grids can be significantly improved by applying Gridgen's elliptic PDE methods. These methods iteratively solve Poisson's equation. While the defaults have been set to provide the nominal grid, the control functions can be fine tuned at any time using the following techniques:

LaPlace (smoothness)
Thomas-Middlecoff (clustering)
Fixed Grid (smoothness)
von Lavante-Hilgenstock-White, and Steger-Sorenson (orthogonality).

+ ground effect test

Structured grids with high degrees of orthogonality and clustering control can also be created using Gridgen's hyperbolic PDE and algebraic extrusion methods. All of the extrusion methods can be applied to 2D grids, surface grids constrained to CAD surfaces, and volume grids. The hyperbolic method is especially well suited for CFD solvers that use overlapping grids but contains features to extrude multi-block abutting grids as well.