Aircraft and Aerospace Vehicle Components
So far the geometry definition tool is quite general and may be used easily for solid modelling of nearly any device if a mathematically exact description of the surface, with controlled gradients and curvatures, is intended. In aerodynamic applications we w ant to make use of knowledge bases from hydrodynamics and gasdynamics. L e. classical airfoil and wing theory, as well as the classical results of slender body theory, transonic and supersonic area rule should determine the choice of functions and parameters. Surface quality should he described with the same accuracy as resulting from refined design methods outlined in the book chapter about the gasdynamic knowledge base. This is achieved by selecting suitable functions (G) when the key* curses axe subdivided into intervals defined by support stations. Slope and curvature control avoids the know n disadvantages of splines while at the same time the number of supports may be very low. if large portions may be modelled by one type of function.
In the process of making this generally described geometry tool to become dedicated geometry generator software for aerospace applications, a focusing on two main classes of surfaces has been found useful. There arc classes of surfaces which arc traditionally ‘spanwise defined’ and others arc ‘axially defined’. Lift-gciterating components like wings primarily belong to the first category w hile fuselages arc usually of the second kind. With this distinction having led to several practical versions of geometry generators, it should not be considered too dogmatically; especially novel configuration concepts in the high Mach number flight regime arc modelled without the above distinction as will be illustrated below, after describing the creating of conventional w ings and fuselages.