The modeling requirements for validating Navier-Stokes computations of a high-lift trapezoidal wing are investigated. This wing has a full-span slat and a full-span ap, and has been tested extensively in the NASA Langley 14-by 22-Foot Wind Tunnel and the NASA Ames 12-Foot Pressure Wind Tunnel. Due to the size of the wing, there are signi cant facility e ects in the data from the 12-Foot wind tunnel. Computational models of the test facility of di ering delity are developed and tested. Results are compared with experimental lift, drag, surface pressures, and velocity pro les. In the computations, a simpli ed, inviscid model of the test-section performs as well as a highdelity, viscous test-section model. Computed results generally compare very well with experimental data at all but the highest angles of attack. A comparison of computational results from both free-air and wind-tunnel simulations at the same lift condition indicates that it is necessary to simulate the wind-tunnel to perform validation using the 12-Foot experimental data. A subsequent grid-re nement study found that enhanced spanwise resolution increased the accuracy of the computed surface pressures at high-angle of attack, and resulted in a computed maximum lift that was 5 above the experimental value.

A series of Navier-Stokes simulations of a complete Boeing 777-200 aircraft con gured for landing is obtained using a structured overset grid process and the OVERFLOW CFD code. At approach conditions, the computed forces for the 777 computation are within 1.5 of experimental data for lift, and within 4 for drag. The computed lift is lower than the experiment at maximum-lift conditions, but shows closer agreement at post-stall conditions. The e ect of sealing a spanwise gap between leading edge elements, and adding a chine onto the nacelle is computed at a high angle of attack. These additions make a signi cant difference in the ow o ver the wing near these elements. Detailed comparisons between computed and experimental surface pressures are shown. Good agreement is demonstrated at lower angles of attack, including a prediction of separated ow on the outboard ap. Introduction Calculating the viscous uid ow over a high-lift Aerospace Engineer. y Chief, Aerospace Operations Modeling O ce. Senior Member AIAA. z Principal Engineer. x Principal Engineer. Senior Member AIAA. Engineer Scientist Specialist. Member AIAA. k Research Engineer.

A n umber 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 ow-elds of both aircraft were simulated using the OVERFLOW solver. A N a vier-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 y ears earlier. The new software was utilized to perform a ow-eld 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. y Chief, Aerospace Operations Modeling O ce. Senior Member AIAA. z Research Engineer. x Principal Engineer. Senior Member AIAA. Engineer Scientist Specialist. Member AIAA. k Principal Engineer.

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Insights and lessons learned from the aerodynamic analysis of a High Wing Transport high-lift configuration are presented. Three-dimensional Navier-Stokes computational fluid dynamics simulations using the OVERFLOW flow solver are compared with high Reynolds-number test data obtained in the NASA Ames 12-Foot Pressure Wind Tunnel facility. Computational analysis of the baseline High Wing Transport high-lift configuration with and without externally blown flap jet effects is presented. Using the developed computational fluid dynamics analysis capability, several aerodynamic investigations, including an assessment of nacelle strake effectiveness and wake vortex prediction, are presented.