Validation of Computed High-Lift Flows with Significant Wind-Tunnel Effects

TLDR

The high‑lift trapezoidal wing, equipped with full‑span slat and flap, has been extensively tested in the NASA Langley 14 × 22‑ft and Ames 12‑ft wind tunnels, where the smaller facility introduces significant size‑related effects. The study investigates the modeling requirements needed to validate Navier‑Stokes computations of this wing. Computational models of the wind‑tunnel test section at varying fidelity were developed and benchmarked against experimental lift, drag, and surface‑pressure data. A simplified inviscid test‑section model matches the high‑fidelity viscous model and agrees well with experimental data except at the highest angles, demonstrating that wind‑tunnel simulation is essential for validating 12‑ft tunnel results.

Abstract

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 flap and has been tested extensively in the NASA Langley 14 x 22-ft Wind Tunnel and the NASA Ames 12-ft Pressure Wind Tunnel. Because of the size of the wing, there are significant facility effects in the data from the 12-ft wind tunnel. Computational models of the test facility of differing fidelity are developed and tested. Results are compared with experimental lift, drag, and surface pressures. In the computations a simplified, inviscid model of the test section performs as well as a high-fidelity, 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-ft wind-tunnel experimental data