R.J. Epstein, D.B. Bliss

Analytical/Numerical Matching (ANM) is a hybrid scheme combining a low-resolution global numerical solution with high-resolution local solutions to form a composite solution. ANM is applied to lifting surfaces in unsteady, compressible, irrotational flow to calculate the unsteady aerodynamic loading and the associated acoustic field. The solution procedure utilizes overlapping smoothed doublets, and local corrections to calculate the doublet strength distribution along the airf oil chord. A smoothing length scale is introduced that is larger than the smallest physical scale, and smaller than the largest physical scale. The global low-resolution solution is calculated numerically using smoothed doublet solutions to the convective wave equation, and converges quickly. Local corrections are done with high-resolution analytical solutions. The global numerical solution is asymptotically matched to the local analytical solutions via a matching solution. The matching solution cancels the global solution in the near-field, and cancels the local solution in the far-field. The ANM composite solution gives both the pressure distribution along the chord of the airf oil and the radiated acoustic field. The method is very robust, offering insensitivity to control point location. No explicit wake geometry is assumed, therefore a fixed or free wake model can be used. ANM provides high resolution calculations from low resolution numerics with analytical corrections, while avoiding the subtlety involving singular integral equations, and their numerical implementation.

First Joint CEAS/AIAA Aeroacoustics Conference, München, 1995

Conference Paper

englisch

21,0 x 29,7 cm, 10 Seiten

DGLR-Bericht, 1995, 1995-01, First Joint CEAS/AIAA Aeroacoustics Conference - Proceedings; S.491-500; 1995; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1995