Numerical Investigation of Slat and Compressibility Effects for a High-Lift Wing

Abstract

Three-dimensional multielement wings are simulated to investigate slat aerodynamics, numerical modeling techniques, and compressibility effects for high-lift ows. The computations are performed by solving both the incompressible and compressible Navier-Stokes equations on structured, overset grids. Turbulence is modeled via the one-equation Spalart-Allmaras model. All of the computed cases include the main wing with a half-span ap de ected to 40 deg. Three leading-edge con gurations of this unswept wing are then considered: no slat, full-span slat, and a three-quarter-span slat. The slat elements are deployed to 6 deg. Computations of the model, which simulates a landing con guration at 10-deg angle of attack and a chord-based Reynolds number of 3.7 £ £ 10 6 , are validated with surface pressure measurements acquired at the NASA Ames 7-by 10-Foot Wind Tunnel. By the observation of the changes to the high-lift ow eld by adding the slat, as well as by varying its spanwise length, a detailed computational assessment of a properly con gured slat is achieved. Moreover, the results increase the computational knowledge of how to model the slat ow physics accurately. For the three-element wing with partspan slat, modeling compressibility can have a large impact on the ow eld solution. Overall, compressibility is small, but it has signi cant global effects on the circulation and ow separation of each element.

Detached-Eddy Simulation of Slat and Flap Aerodynamics for a High-Lift Wing

“…Figure 13 details the time convergence history for the DES run, which shows that the flow is definitely unsteady with an average lift coefficient of a little over C L = 0.2, which compares well with the results of Ref. 15. 14a, 14b, 14c, and 14d).…”

“…4 and 5). When this geometry was modeled previously, 15 the Chimera overset grid proces 29,30 was used due to the combination of one-, two-, and three-element airfoil sections that abut one another. The use of unstructured grids has greatly reduced the amount of time required for grid generation, and should show itself to be a valuable tool for this type of configuration.…”

“…For example, Rogers, Cao, and Su 14 applied and evaluated the overset grid method for a Boeing 747PD high-lift configuration. Also, Baker, et al 15 have applied the overset grid method for a part-span slat/part-span flap configuration using the Spalart-Almaras turbulence model.…”