Abstract

An automated, simulation-based aircraft design process allows for the prediction of unanticipated problems early in
the design stage, leading to reduced turn-around time and development cost. Having reliable, and affordable (fast)
design tools is crucial to achieving this level of automation in design process. An example of this is illustrated for
a jet trainer aircraft using two aircraft design codes: Jet Designer and CEASIOM. A set of aerodynamic methods
with different degrees of fidelity and computational expense is considered, with the limitations of each method
provided. In particular, this paper examines the challenges that CFD-based aircraft design poses to a designer,
including: a) the cost of generation of large data tables, b) the automated handling of geometry, c) treating control
surface deflections, d) and calculation of dynamic derivatives using CFD. A Kriging-based sampling approach
was used for generating aerodynamic tables with a reasonable computational cost compared with a brute-force
approach. For Euler calculations, an automated CAD and mesh generation approach from a geometry description
was used. It is demonstrated that application of Euler solutions to low fidelity aircraft geometry shows the expected
design trends. Also, results show that the wave drag at transonic speeds can be predicted with Euler equations, but
not with vortex lattice or Digital DATCOM. The treatment of control surface deflections was also investigated for
the vortex lattice solver and the Euler code. Transpiration boundary condition approach was used in the Euler code
to model the flap surface movements, although this approach is limited to small control surface deflections. The
calculated aero tables form each aero source were used next to study the vehicle flying qualities. Results presented
demonstrate the validity and feasibility of the simulation-based approach for aircraft conceptual design.

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