Detached-eddy simulation of fighter aircraft at high alpha

James R. Forsythe, Kyle Squires, Kenneth E. Wurtzler, Philippe R. Spalart

Research output: Chapter in Book/Report/Conference proceedingConference contribution

29 Scopus citations

Abstract

Detached-Eddy Simulation (DES) is used to predict the massively separated flow around an F-15E at 65° angle-of-attack. The calculations are performed at flight test conditions corresponding to a chord-based Reynolds number of 13.6×106 and Mach number of 0.3. Flow field solutions are obtained using using Cobalt. The calculations were performed using unstructured grids in which the baseline mesh is comprised of 5.9 × 106 cells with prisms in the boundary layers and isotropic tetrahedra in other regions. Mesh spacings from solid surfaces to the first cell center nearest the wall were within one viscous unit. Baseline calculations were performed on a half aircraft by assuming symmetry. Modeling the full aircraft by mirroring the grid across the symmetry plane was compared to the baseline calculations. The influence of the mesh size was assessed using calculations performed on two other grids: a coarser grid of 2.85 × 106 cells and a finer mesh of 10 × 106 cells. In addition, the influence of the timestep is investigated using the baseline mesh and two simulations with timesteps a factor of two and a factor of four larger than the the value used in the baseline calculations. DES predictions are assessed via comparison to Boeing's stability and control database as well as solutions on the same grids of the Reynolds-averaged Navier-Stokes (RANS) equations. Both RANS and DES predictions have only a weak dependence for integrated forces on the grid density for the range examined, suggesting a grid-converged solution. DES predictions show that the wake region is characterized by complex and chaotic threedimensional structures exhibiting a reasonable range of length and time scales. Timedependent RANS predictions were obtained using the Spalart-Allmaras model and evolve to steady solutions. In general, both RANS and DES predictions of averaged quantities exhibit favorable agreement with the flight-test data. DES predictions of the lift, drag, and pitching moment coefficients, which were averaged over as many as 150 inertial timescales, agree more favorably with the flight-test data than the RANS results, although both methods are within 10% of the stability and control database.

Original languageEnglish (US)
Title of host publication40th AIAA Aerospace Sciences Meeting and Exhibit
StatePublished - 2002
Event40th AIAA Aerospace Sciences Meeting and Exhibit 2002 - Reno, NV, United States
Duration: Jan 14 2002Jan 17 2002

Other

Other40th AIAA Aerospace Sciences Meeting and Exhibit 2002
CountryUnited States
CityReno, NV
Period1/14/021/17/02

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ASJC Scopus subject areas

  • Space and Planetary Science
  • Aerospace Engineering

Cite this

Forsythe, J. R., Squires, K., Wurtzler, K. E., & Spalart, P. R. (2002). Detached-eddy simulation of fighter aircraft at high alpha. In 40th AIAA Aerospace Sciences Meeting and Exhibit