STS-107 Investigation Ascent CFD Support

Abstract

This paper provides an overview of the computational fluid dynamics analysis of the ascent of the Space Shuttle Launch Vehicle during the investigation of the STS-107 accident. The analysis included both steady-state and unsteady calculations performed with the Overflow and Cart3D flow solvers. The unsteady calculations include moving body, six degree-of-freedom simulations of foam debris shed from the region of the left bipod-ramp of the vehicle. Many such debris trajectories were computed, some of which impacted the vehicle. The analysis provided an estimate of the speed at which such a piece of debris would strike the wing leading edge of the Shuttle Orbiter. These results were supplied to the Columbia Accident Investigation Board, and guided the choice of the impact velocity and foam size selected for the foam-firing test done as part of the investigation. This testing subsequently showed that it was possible for a piece of foam debris to cause massive damage to the Shuttle Orbiter wing Reinforced-Carbon-Carbon panels and T-seals, creating a breach where hot gases could enter the wing structure during reentry.

High-order compact finite-difference methods on general overset grids

“…The governing partial differential equations are solved separately on each component, and domain connectivity is obtained through the use of interpolation along the boundaries between overlapping grids. While originally developed as a means to address complex geometries (e.g., [9,10]), overset-grid methods have also been employed to simulate multiple bodies in relative motion (e.g., [11]) and provide flexible grid-adaptation through localized refinement/coarsening in a computational domain (e.g., [12,13]). The overset-grid paradigm may also serve as a domain-decomposition paradigm for exploiting massively parallel computing platforms [14].…”

Compact upwind schemes on adaptive octrees

“…Examples from the authors research includes foam debris shedding from the space shuttle launch vehicle (SSLV) [1,2], where trajectory predictions of dislodged foam, with a characteristic dimension of roughly one inch, are required over a vehicle hundreds of feet in length. In a jet impinging upon a ground plane in crossflow [3], the jet shear layer contains high-frequency oscillations with Strouhal number roughly St ¼ Oð10 À3 Þ, a von Kármán street forms behind the cylindrical jet with St ¼ Oð10 À1 Þ, and the ground vortex ''puffs" with a frequency of St ¼ Oð10 1 Þ.…”

Advances in Distance-Based Hole Cuts on Overset Grids

“…[1][2][3][4][5][6] Over the years, various methods have been developed for domain connectivity or overset grid assembly. [7][8][9][10][11][12][13][14][15] Since both the surface and volume grids are allowed to overlap arbitrarily, grid points that fall inside solid bodies or outside the computational domain need to be identified and excluded from the process of solving the governing field equations.…”