Aerodynamic Calculation of Complex Three-Dimensional Configurations

A three-dimensio nal code called ECOPAN, based on an "inner Dirichlet" boundary condition, has been developed at ONER A. It is currently used to calculate a wide variety of complex aerodynamic configurations. Thus, the future European Ariane 5 launch vehicle has been evaluated in the takeoff phase. It is shown that the change from the automatic version to the Hermes version results in a decrease of the launcher total stability. This decrease is moderated by a favorable interaction of Hermes wake on the lower part of the launcher. A complete Airbus aircraft has been calculated in its takeoff configuration with flaps and slats extended and with a simulation of engine primary and secondary fluxes. The increase in lift due to a plane of symmetry simulating the ground effect has been estimated to be of the order of a few percents, which is in agreement with flight test results. In these two applications the ECOPAN code has demonstrated its versatility, its operational status, and its aptitude to perform parametric analyses in subsonic flow.