An Overview of the Characterization of the Space Launch System Aerodynamic Environments

Blevins, John; Campbell, John R.; Bennett, David; Rausch, Russ D.; Gomez, Reynaldo J.; Kiris, Cetin C.

doi:10.2514/6.2014-1253

Cited by 14 publications

(7 citation statements)

References 10 publications

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“…Wind tunnel testing with all of the core and SRB engine plumes was not possible, therefore, experimental simulations of the BSM exhaust plumes were conducted to obtain their effect on the flowfield as well as any plume interactions on the core, SRBs, and associated shocks. The measurements taken during the test will be used to verify the computational fluid dynamics (CFD) codes [3,4] that are required to build the booster separation database [5] because it is the only method available to simulate all plumes and their interactions. The separation database will be used by analysts modeling the vehicle, specifically the Guidance, Navigation & Control team, who will be simulating the booster separation trajectory.…”

Section: Introductionmentioning

confidence: 99%

Space Launch System Booster Separation Supersonic Powered Testing with Surface and Off-body Measurements

Winski

Danehy

Watkins

et al. 2019

AIAA Scitech 2019 Forum

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A wind tunnel test was run in the NASA Langley Unitary Plan Wind Tunnel simulating the separation of the two solid rocket boosters (SRB) from the core stage of the NASA Space Launch System (SLS). The test was run on a 0.9% scale model of the SLS Block 1B Cargo (27005) configuration and the SLS Block 1B Crew (28005) configuration at a Mach of 4.0. High pressure air was used to simulate plumes from the booster separation motors located at the nose and aft skirt of the two boosters. Force and moment data were taken on both SRBs and on the core stage. Schlieren still photos and video were recorded throughout testing. A set of points were acquired using Cross-correlation Doppler Global Velocimetry (CCDGV) readings to get 3 component velocity measurements between the core and the left-hand SRB. The CCDGV laser was utilized to record flow visualization in the same location, between the core and the left-hand SRB. Pressure Sensitive Paint data were taken on a separate set of runs. Computational Fluid Dynamics (CFD) runs were computed on a subset of the wind tunnel data points for comparison. A combination of the force/moment, CCDGV and Pressure Sensitive Paint (PSP) data (as well as schlieren images) at the CFD-specified test conditions will be used to validate the CFD simulations that will be used to build an SLS booster separation database at flight conditions.Notice to the Reader -The Space Launch System, including its predicted performance and certain other features and characteristics, has been defined by the U.S. Government to be Sensitive But Unclassified (SBU). Information deemed to be SBU requires special protection and may not be disclosed to an international audience. To comply with SBU restrictions, details such as absolute values have been removed from some plots and figures in this paper. It is the opinion of the authors that despite these alterations, there is no loss of meaningful technical content.

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Section: Introductionmentioning

confidence: 99%

Space Launch System Booster Separation Supersonic Powered Testing with Surface and Off-body Measurements

Winski

Danehy

Watkins

et al. 2019

AIAA Scitech 2019 Forum

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“…During the ascent, the ELV is exposed to high dynamic pressures leading to substantial aerodynamic loads. This is accompanied by unsteady aerodynamics in the transonic region [28]. The launcher is also subject to various disturbances.…”

Section: A Space Launcher Modelmentioning

confidence: 99%

Finite Horizon Worst-Case Analysis of Linear Time-Varying Systems Applied to Launch Vehicle

Biertümpfel¹,

Pholdee²,

Bennani³

et al. 2021

Preprint

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This paper presents an approach to compute the worst-case gain of the interconnection of a finite time horizon linear time-variant system and a perturbation. The input/output behavior of the uncertainty is described by integral quadratic constraints (IQCs). A condition for the worst-case gain of such an interconnection can be formulated using dissipation theory as a parameterized Riccati differential equation, which depends on the chosen IQC multiplier. A nonlinear optimization problem is formulated to minimize the upper bound of the worst-case gain over a set of admissible IQC multipliers. This problem can be efficiently solved with a custom-tailored logarithm scaled, adaptive differential evolution algorithm. It provides a fast alternative to similar approaches based on solving semidefinite programs. The algorithm is applied to the worst-case aerodynamic load analysis for an expendable launch vehicle (ELV). The worst-case load of the uncertain ELV is calculated under wind turbulence during the atmospheric ascend and compared to results from nonlinear simulation.

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“…25,26 This is aggravated by the high dynamic pressures during the ascent leading to substantial aerodynamic loads accompanied by unsteady aerodynamics in the transonic region. 27,28 The launcher is also subject to a variety of disturbances the most influential of these is wind. 29…”

Section: Launcher Modelmentioning

confidence: 99%

Time‐varying robustness analysis of launch vehicles under thrust perturbations

2021

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This article presents a robustness analysis for launch vehicles during atmospheric ascent. It is based on recent advances in the worst-case analysis of uncertain, finite horizon linear time-varying (LTV) systems. Integral quadratic constraints are used to represent the uncertainties leading to a worst-case gain condition based on a parameterized Riccati differential equation (RDE). This framework readily covers certain parametric uncertainties, for example, aerodynamic uncertainties. However, the effects of thrust perturbations are inherently harder to address. They directly result in mass and balance uncertainties, and a deviation from the planned trajectory. The latter amounts to a shift from the nominal/reference trajectory that has to be accounted for. Since thrust is proportional to the mass change of the launch vehicle, the thrust uncertainty is modeled as an external disturbance acting on the system. In order to cover the deviation from the reference trajectory, a dynamic uncertainty model is added in the analysis. A worst-case aerodynamic loads and lateral drift analysis under wind disturbances is performed. The LTV results are validated against Monte Carlo simulations of the space launcher's nonlinear model.

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An Overview of the Characterization of the Space Launch System Aerodynamic Environments

Cited by 14 publications

References 10 publications

Space Launch System Booster Separation Supersonic Powered Testing with Surface and Off-body Measurements

Space Launch System Booster Separation Supersonic Powered Testing with Surface and Off-body Measurements

Finite Horizon Worst-Case Analysis of Linear Time-Varying Systems Applied to Launch Vehicle

Time‐varying robustness analysis of launch vehicles under thrust perturbations

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