Validation of a near-body and off-body grid partitioning methodology for aircraft aerodynamic performance prediction

Abstract

This article describes a methodology based on overset grid techniques that enables the mesh generation process for aircraft configurations to be simplified and shortened. It is based on the key-concept of partitioning the computational domain: the near-body areas are meshed by a set of body-fitted structured grids while the off-body domain is treated with an automated Cartesian grid method. This state-of-the-art combination allows a complex geometry to be considered as the sum of simple elements such as fuselage, wing, winglets, or tailplanes. As a consequence, the ONERA approach exhibits several decisive advantages: easiness, flexibility, rapid implementation, Cartesian grid adaptation. In order to apply and validate the overall methodology, a well-known configuration, the NASA Common Research Model, has been chosen. It is an open geometry representative of current wide-body commercial aircraft which has been used in the international AIAA Drag Prediction Workshops. In this paper, the complete meshing procedure is described. Then, for near-field and far-field drag as well as for local analyses, the results obtained with this new overset strategy are compared to the data produced by the common point-matched Drag Prediction Workshop grids and a very satisfactory agreement is observed. Moreover, some advantages of Cartesian grid adaptation are highlighted.