An Overview of NASA Langley Low-Speed CFD Contributions to the Space Launch System Program

Pomeroy, Brent W.

doi:10.2514/6.2023-0236

Cited by 4 publications

References 26 publications

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Computational Techniques to Generate Space Launch System Aerodynamic Databases

Deere,

Krist,

Ratnayake

et al. 2024

Journal of Spacecraft and Rockets

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This document describes the reasoning and trade studies used to evaluate tools for constructing the aerodynamic lineload databases for the liftoff and transition phases of flight for the Space Launch System. Three computational fluid dynamics codes (USM3D, FUN3D, and Kestrel) were investigated with various turbulence models as well as detached eddy simulation variants for the launch vehicle in free air and in proximity to the tower. Decisions were made mostly based on results from brief developmental studies performed in response to specific, unforeseen challenges that were encountered in the analysis of a given configuration. The need to develop databases in a timely manner, as well as to accurately capture the expected leeward-wake flowfield characteristics, led to the selection of the Kestrel flow solver with its delayed detached eddy simulation method, the Spalart–Allmaras turbulence model, and the adaptive mesh refinement capability in the off-body Cartesian grid region.

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Computational Techniques to Generate Space Launch System Aerodynamic Databases

Deere,

Krist,

Ratnayake

et al. 2024

Journal of Spacecraft and Rockets

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Unsteady Surface Pressure Characterization on Launch Vehicle in Liftoff Configuration

Mears,

Nikoueeyan,

Hind

et al. 2024

Journal of Spacecraft and Rockets

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Acquisition of unsteady pressure using remote scanners can provide practical advantages over making the same measurements directly using flush-mounted pressure transducers. However, pneumatic distortion of the signal is introduced by the tubing between the sensing module and surface port. This typically limits the usefulness of such measurements to averaged, steady data only, restricting the application of pressure scanners for unsteady pressure measurements in wind-tunnel and flight-testing applications. In this work, unsteady pressure on the surface of a 1.75%-scale model of the NASA Space Launch System Block 1B Cargo vehicle was remotely measured using an electronic scanning pressure module at the NASA Langley Research Center 14-by 22-Foot Subsonic Tunnel. Subsequent reconstruction using an empirically tuned, Wiener-filtered inverse transfer function produced excellent agreement compared to nearby surface-mounted transducers within a usable bandwidth of approximately 500 Hz. Interactions between the launch vehicle and the support tower produced strong oscillations that were absent in the vehicle-alone configuration, and it is likely that the wake interaction leads to a resonant flow response when the launch tower is immediately downstream of the vehicle.

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