Computational Aerodynamics Analysis Results

Computational aerodynamics (CA) analyses use digital computers to model airflow about an air vehicle to obtain estimates of overall forces and moments, such as lift and drag, of an air vehicle (or a component of an air vehicle) or a more detailed knowledge of the air flow properties (including pressures, temperatures, velocities, etc.), or both. Computational aerodynamics analyses are complementary to theoretical analyses and experimental tests, such as wind-tunnel and flight tests.

CA methods include low-fidelity semi-empirical or engineering methods (using resources such as digital DATCOM), potential-flow methods (including panel methods and vortex-lattice methods), and high-fidelity computational fluid dynamics (CFD), which are numerical approximations to the partial-differential equations that describe fluid motion, such as the full-potential equations or Euler and Navier-Stokes equations. Semi-empirical engineering methods typically result in estimates of overall forces and moments, require few computational resources but are the least accurate, and are usually used for conceptual design or trade studies. Potential flow methods, which are limited to inviscid and steady flows, but which may also include some viscous effect approximations through a separate boundary layer analysis, result in surface pressures and integrated forces and moments, and are usually used for more detailed analysis and design. CFD methods may require the use of high-performance computing resources and result in highly detailed flow results, including forces and moments of the air vehicle and all modeled components, as well as all flow variables, such as pressures, temperatures, and velocities throughout the flow field. CFD analyses can be highly accurate. The accuracy of a CA analysis requires an understanding of the assumptions inherent in the different models, as well as potential sources of error, and requires the appropriate use of the computational model and analysis software.

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