Benchmark Super Critical Wing Home

The Benchmark Supercritical Wing (BSCW) was chosen as the configuration for the workshop. The model has geometric simplicity, and the test conditions are such that the flow field has demonstrated complexities. The test conditions for the workshop have been chosen to capture increasing complexities. The flow conditions used for AePW-1 were challenging. Shock-induced separated flow dominates the upper surface and the aft portion of the lower surface at the Mach 0.85, 5° angle of attack cases that were simulated. Separation assessment was performed on the experimental data for the OTT test. Using these results as a guide, cases just outside of the separated flow regime will be emphasized for AePW-2. Steady and forced oscillation analyses will be conducted at Mach 0.7, 3° angle of attack; unforced (steady) and flutter analyses will be conducted at Mach 0.74, 0° angle of attack. An optional case, Case 3, will be re-analysis of the AePW-1 case (Mach 0.85, 5° angle of attack), encouraging the application of higher fidelity tools and detailing spatial and temporal convergence issues.

Wind Tunnel Model: The Benchmark SuperCritical Wing (BSCW) was tested in the NASA Langley Transonic Dynamics Tunnel (TDT) in two test entries. The most recent test served as the basis for AePW-1; testing was performed on the oscillating turntable (OTT) which provided forced pitch oscillation data. A prior test was performed on a flexible mount system, denoted the pitch and plunge apparatus (PAPA). Aeroelastic testing was performed for the model on the PAPA, where the mount system provides low-frequency flexible modes that emulate a plunge mode and a pitch mode. The PAPA data consists of steady data and unsteady data at flutter points. Data from both tests will be utilized for comparison with simulation data in AePW-2.

The BSCW airfoil is a NASA SC(2)-0414. The airfoil designation indicates that it was part of the 2nd generation of designed supercritical airfoils, with a design normal force coefficient of 0.4 and a 14% thickness to chord ratio. The planform is rectangular with a wing tip cap shaped as a tip of revolution. The PAPA test was conducted with several flow transition strip configurations; only data using the 35 grit will be used for these comparisons. For the OTT test, the boundary layer transition was fixed at 7.5% chord using size 30 grit. All cases has transition grit on both the upper and lower wing surfaces.

The wing was designed with the goal of being rigid; the spanwise first bending mode of the wing itself has a frequency of 24.1 Hz. The flexible modes that will be modeled in the current effort are provided through the flexible mount system.

The models instrumentation consists of chord-wise rows of in-situ unsteady pressure transducers; for the PAPA test, there were populated rows at the 60% and 95% span stations. For the OTT test, the 95% span station row was not populated with transducers.

Previous Computations and Results Summary The BSCW case served as a semi-blind test case for AePW-1. There were very small plot of some of the data previously published, but in insufficient detail to be truly useful to the analysis teams. Eight teams performed analyses of the BSCW; they used Reynolds-Averaged Navier-Stokes flow solvers exercised assuming that the wing had a rigid structure. Both steady-state and forced oscillation computations were performed by each team, with some teams choosing to perform time-accurate simulations even for the unforced system case. The results of these calculations were compared with each other and with the experimental data. The steady-state results from the computations capture many of the flow features of a classical supercritical airfoil pressure distribution. The most dominant feature of the oscillatory results is the upper surface shock dynamics. Substantial variations were observed among the computational solutions as well as differences relative to the experimental data. Follow-on studies have included hybrid RANS-LES simulations.