Partial Pressure Field for Airfoil Wave Drag

Abstract

Far-field drag prediction methods have proven to be effective at capturing drag sources in both computational fluid dynamics and wind-tunnel testing analyses. Near-field decomposition, on the other hand, has been neglected due to the failure to divide pressure drag directly into its contributions to both form and wave drag. The work presented in this paper is an extension of previous research conducted into partial pressure fields that allow such a near-field drag decomposition. In particular, the current paper proposes a new partial pressure field that captures wave drag sources in two-dimensional compressible viscous flow. Pressure decompositions are performed on the conventional NACA0012 and RAE2822 airfoils, and the results are compared to those obtained by classical far-field decomposition, with reference data from previous studies providing a means of verification. Finally, the slotted natural laminar-flow airfoil, the S207, is analyzed to test the applicability of the decomposition method on multielement airfoils that are considered for next-generation aircraft design. It is demonstrated that an adjusted compressible pressure field captures wave drag as a reliable near-field method that correlates closely with the traditional far-field methods, particularly for typical transonic cases.