Aircraft Surface Tolerances for Enhanced Repair, Operations and Design
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The ASTEROID program brings together the various ESDU methods for the calculation of excrescence drag due to steps, ridges, grooves and cavities on the external surfaces of aircraft. The app provides a simple interface that enables users to define the excrescences and then calculate the drag increments within a few minutes.
ASTEROID integrates the programs associated with ESDU 75031, ESDU 74036 and ESDU 75028 within the context of a specified and predetermined aircraft flow field. Multiple excrescence geometries can be specified on selected aircraft major components (i.e. a wing upper or lower surface, fuselage, nacelle, horizontal tail or fin). The app first asks the user to select an aircraft type (e.g. single-aisle transonic airliner, low-speed commuter airliner, etc) from a list and to choose an appropriate cruise Mach number for consideration. The app then allocates the appropriate pre-generated local flow field so that typical flow conditions (including flow direction) at each excrescence can be determined. The flow data for the single-aisle and low-speed commuter aircraft are presented for the whole airframe, together with a range of wings representative of short-, medium- and long- range jet transports, and a blended-wing body design.
Excrescence geometries are then specified either as circular cavities or as multi-node excrescences, which can be closed (e.g. to model a repair plate or cover) or open (e.g. to model a control surface gap). The edges of the excrescence can be characterised as steps (with or without edge treatments), rectangular or square ridges, grooves or gaps (with or without sealing).
When the excrescences have been defined, the app automatically selects the method from the appropriate Data Item and calculates the drag coefficients based on both the excrescence and aircraft reference areas. The aircraft drag coefficient penalty summed for all excrescences is also calculated.
Two versions of the Tool are provided:
- ASTEROID - the full package with various aircraft / wing geometries provided, together with representative viscous aerodynamic data.
- ASTEROID fp - a 'flat plate' version of the tool where all flow conditions are specified by the user, thereby extending its applicability to missiles, rockets, drones etc and non-aeronautical applications.
|Toolbox ASTEROID Run||
|Toolbox ASTEROID fp Run||