A Partial Pressure Field For Airfoil Wave Drag

Far-field drag prediction methods have proven to be effective at capturing drag sources in both CFD and wind tunnel testing analyses. Near-field decomposition on the other hand has been neglected due to the failure to relate pressure and skin friction drag directly to phenomena that cause them. The work presented in this paper is an extension of previous research conducted into partial pressure fields that allow 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 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, S207, is analyzed to test the applicability of the decomposition method on multi-element airfoils that are considered for next-generation aircraft design. It is demonstrated that an adjusted compressible pressure field captures a wave drag as a reliable near-field method that correlates closely with the traditional far-field methods, particularly in typical transonic cases.