Advances in overset CFD processes applied to subsonic high-lift aircraft

A number of grid-generation and CFD-process software tools have been developed which greatly improve the ability to perform overset CFD analysis of complex con gurations. These tools have been applied to the task of generating grids and computing the ow eld about two di erent high-lift aircraft con gured for landing: a Boeing 777-200, and a High-Wing Transport with externally blown aps. The high-lift owelds of both aircraft were simulated using the OVERFLOW solver. A Navier-Stokes simulation of a complete Boeing 777-200 aircraft con gured for landing was obtained in less than 50 labor days with a lift coe cient which di ers from experimental data by only 1.2%. This is an order of magnitude reduction in the cycle time for the entire computational process compared to a similar high-lift simulation e ort that took place two years earlier. The new software was utilized to perform a oweld analysis of a ap-rigging modi cation for the Boeing 777-200 aircraft in only four days. The software was also utilized to simplify Aerospace Engineer. yChief, Aerospace Operations Modeling O ce. Senior Member AIAA. zResearch Engineer. xPrincipal Engineer. Senior Member AIAA. {Engineer/Scientist Specialist. Member AIAA. kPrincipal Engineer. Copyright c 2000 by the American Institute of Aeronautics and Astronautics, Inc. No copyright is asserted in the United States under Title 17, U.S. Code. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Governmental Purposes. All other rights are reserved by the copyright owner. grid generation of the High-Wing Transport for many di erent geometric con gurations. The reductions in computational cycle time are primarily the result of the use of an automatic script system that streamlines the overset grid preparation process. Analysis of the process shows that over-setting the the grid system is now the most labor-intensive part of a single-point analysis; however, for multi-point analyses, multiple viscous ow-solver runs are costly.