Abstract:
The general problem of measuring bluff-body aerodynamic load maps is considered, and simplified using a Fourier series representation Six-component aerodynamic load coefficients have been measured in a low-speed wind tunnel with 1 degree azimuthal resolution, about the needed axes for over 30 models using the Continuous Rotation method. Test cases include both explorations on practical vehicle shapes, and systematic parameter variations on canonical shapes, including open and closed cylinders, flat and long rectangular containers. From the load maps for different aspect ratios, different approaches to interpolation and generalization are considered. Interpolating Fourier coefficients proves to be efficient and accurate. The efficacy of such interpolation is shown where the aerodynamics on an empty engine canister are quickly estimated by reference to the interpolated data for a circular cylinder of aspect ratio 1.9. The possibility of using combinations of canonical shapes to approximate the load map for a complex object such as a road vehicle, is also seen from the success of a combination of airloads for a cylinder and rectangular box, in approximating several of the aerodynamic load coefficient variations for a road vehicle model.