Output-Adaptive Tetrahedral Cut-Cell Validation for Sonic Boom Prediction

Park, Michael A.; Darmofal, David L.

doi:10.2514/6.2008-6594

Cited by 15 publications

(8 citation statements)

References 48 publications

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“…Significant success has been reported for the application of these techniques to steady problems. [10][11][12][13][14] In general, optimization and mesh adaptation for large-scale unsteady flows based on adjoint methods require a time-dependent implementation of the equations. Considerable effort by a number of research groups is being focused in this area, and examples of the use of such approaches have recently emerged.…”

Section: Introductionmentioning

confidence: 99%

Multi-point Adjoint-Based Design of Tilt-Rotors in a Noninertial Reference Frame

Jones

Nielsen

Lee-Rausch

et al. 2014

10th AIAA Multidisciplinary Design Optimization Conference

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Optimization of tilt-rotor systems requires the consideration of performance at multiple design points. In the current study, an adjoint-based optimization of a tilt-rotor blade is considered. The optimization seeks to simultaneously maximize the rotorcraft figure of merit in hover and the propulsive efficiency in airplane-mode for a tilt-rotor system. The design is subject to minimum thrust constraints imposed at each design point. The rotor flowfields at each design point are cast as steady-state problems in a noninertial reference frame. Geometric design variables used in the study to control blade shape include: thickness, camber, twist, and taper represented by as many as 123 separate design variables. Performance weighting of each operational mode is considered in the formulation of the composite objective function, and a build up of increasing geometric degrees of freedom is used to isolate the impact of selected design variables. In all cases considered, the resulting designs successfully increase both the hover figure of merit and the airplane-mode propulsive efficiency for a rotor designed with classical techniques.

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Section: Introductionmentioning

confidence: 99%

Multi-point Adjoint-Based Design of Tilt-Rotors in a Noninertial Reference Frame

Jones

Nielsen

Lee-Rausch

et al. 2014

10th AIAA Multidisciplinary Design Optimization Conference

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“…This adaptive process is applied multiple times until the resolved pressure signature at the sensor location is available. The initial and final symmetry plane grid of an axisymmetric configuration 45 are shown in Fig. 9 to illustrate this process.…”

Section: Iiie Fun3d-adjointmentioning

confidence: 99%

Summary of the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop

Park

Aftosmis²,

Campbell³

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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The Supersonics Project of the NASA Fundamental Aeronautics Program organized an internal sonic boom workshop to evaluate near-and mid-field sonic boom prediction capability at the Fundamental Aeronautics Annual Meeting in Atlanta, Georgia on October 8, 2008. Workshop participants computed sonic boom signatures for three non-lifting bodies and two lifting configurations. A cone-cylinder, parabolic, and quartic bodies of revolution comprised the non-lifting cases. The lifting configurations were a simple 69-degree delta wing body and a complete low-boom transport configuration designed during the High Speed Research Project in the 1990s with wing, body, tail, nacelle, and boundary layer diverter components. The AIRPLANE, Cart3D, FUN3D, and USM3D flow solvers were employed with the ANET signature propagation tool, output-based adaptation, and a priori adaptation based on freestream Mach number and angle of attack. Results were presented orally at the workshop. This article documents the workshop, results, and provides context on previously available and recently developed methods.

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“…7 In addition, if the enrichment is non-directional, it can create more cells in the propagation direction, thus increasing the accumulated dissipation. Good results at larger distances have been obtained using error-driven adjoint-based grid adaptation, 8,9 but the multiple runs required of both the flow and adjoint solvers can make the process cumbersome. A recent paper using a feature-based grid optimization method 10 has shown promising results without the need for the adjoint information.…”

Section: Introductionmentioning

confidence: 99%

Efficient Unstructured Grid Adaptation Methods for Sonic Boom Prediction

Campbell

Carter

Deere

et al. 2008

26th AIAA Applied Aerodynamics Conference

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This paper examines the use of two grid adaptation methods to improve the accuracy of the near-to-mid field pressure signature prediction of supersonic aircraft computed using the USM3D unstructured grid flow solver. The first method (ADV) is an interactive adaptation process that uses grid movement rather than enrichment to more accurately resolve the expansion and compression waves. The second method (SSGRID) uses an a priori adaptation approach to stretch and shear the original unstructured grid to align the grid with the pressure waves and reduce the cell count required to achieve an accurate signature prediction at a given distance from the vehicle. Both methods initially create negative volume cells that are repaired in a module in the ADV code. While both approaches provide significant improvements in the near field signature (< 3 body lengths) relative to a baseline grid without increasing the number of grid points, only the SSGRID approach allows the details of the signature to be accurately computed at mid-field distances (3-10 body lengths) for direct use with mid-field-to-ground boom propagation codes. NomenclatureΔp/p = (local static pressure -free-stream static pressure)/free-stream static pressure H = vertical distance from body to boom measurement station L = reference length x = distance in the streamwise direction Xcone = distance in the streamwise direction relative to initial shock

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Output-Adaptive Tetrahedral Cut-Cell Validation for Sonic Boom Prediction

Cited by 15 publications

References 48 publications

Multi-point Adjoint-Based Design of Tilt-Rotors in a Noninertial Reference Frame

Multi-point Adjoint-Based Design of Tilt-Rotors in a Noninertial Reference Frame

Summary of the 2008 NASA Fundamental Aeronautics Program Sonic Boom Prediction Workshop

Efficient Unstructured Grid Adaptation Methods for Sonic Boom Prediction

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