Design and optimization software based on the OC method

The OC method has proven to be a very flexible design tool requiring only a few input parameters for obtaining a wide vancty of configurations w ith supersonic leading edges, plus (and that’s the attractive feature) it also gives results for the complete flow field and lift and wave drag of the configuration. In this situation a flexible definition of the 3 functions (Уїсс* *юс – an<* °f ICC arc length s. see Figure 49) is most important for rapid prc-dcsign and optimisation studies. The first application software illustrated below combines the OC method with geometry input used in a more general configuration generator outlined in the next book chapter. The latter makes possible a definition of curves with piecewise analytic structure and control of first to third derivatives which arc needed for the calculation of local cone axes as depicted in Figure 50.

The WIPAR interactive code

A versatile computational tool, the ‘Wavender Interactive Parameter Adjustment Rou­tine ♦ WIPAR” – (103). {104) was written for usage on graphic workstations, allowing for a fast and educational display of the resulting configurations and aerodynamic coefficients at design conditions. Some features of this powerful software are illustrated in Figure 51: The windows environment with various adjustment sliders, quick look diagrams and key results displayed make this computer code a suitable baseline for a hypersonic configuration design expert sys­tem. Various configuration examples have been studied and some have been manufactured for experimental investigation in wind tunnels Experiments in the subsonic Mach number regime have been carried out for a wavender similar to the configuration depicted in Figure 51. which was optimized for Mach 4. Results confirm conclusions that wavcridcrs based on the OC con­cept may also have quite favorable aerodynamic characteristics in the low speed regime [ 105).

Aerospace vehicle and SCT aircraft optimization studies based on WIPAR

The WIPAR software is used for an implementation in practical aircraft and aerospace vehicle design systems. For improved modelling of viscous flows and thermal loads, refined methods for boundary layer and heat transfer have been developed and coupled with the design program (106). (107).

With the main thrust of wavender applications so far being directed toward aerospace vehicle operation at hypersonic Mach numbers, an alternative use is proposed for the layout of aircraft wings for high speed transport at even the lower supersonic Mach numbers 1108]. Here the high Mach number design cases arc found to have remarkably good L/D ratios and are there­fore investigated further, namely regarding the influence of sweep on the occurrence of bound­ary layer instabilities and the potential of such wings for laminar flow control. Flexibility in creating configurations for missions in the supersonic as well as in the hypersonic flight regime makes the wavender concept attractive for a vanety of high speed transport concepts. Investiga­tions on a series of configurations derived from WIPAR generated shapes have already been studied for TSTO missions using a multidisciplinary aircraft design program 1109).

Propulsion integration on OC nave riders

The flow field including streamlines between the lower surface of a wavender and the oblique shock is readily available for OC waveriden at design conditions. This may be used for adding stream-aligned surfaces like the propulsion casing, and furthermore, flow conditions at the inlet capture curve ("ICC*) may be input for internal flow simulation of the propulsion unit. This way generic wavender configurations with a flexibility obtained using the OC concept are ideal input for design considerations beyond purely aerodynamic aspects: Multidisciplinary design optimization of realistic vehicles will require a synchronized development of aerody­namic. structural, acroclastic and propulsive components, among many other considerations. Some aspects are already studied in the design of wavcridcrs with integrated propulsion includ­ing inlets and nozzles (110|.

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