Sonic Boom Computations for Double-Cone Configuration Using CFL3D, FUN3D and Full-Potential Codes

Kandil, Osama A.; Ozcer, Isik

doi:10.2514/6.2006-414

Cited by 7 publications

(8 citation statements)

References 4 publications

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“…The same case was employed to evaluate [18] and then validate [19] a parallel adaptive body-fitted grid approach. This configuration has also been used by other researchers to evaluate their signature prediction techniques [5,8]. The pressure integral output function was defined as a cylinder, six body lengths in radius, centered about the geometry axis.…”

Section: A Double-cone Cylindermentioning

confidence: 99%

“…To improve alignment, isotropic unstructured grids are stretched to align the tetrahedra with the freestream Mach angle to improve signal propagation for initial grids [3]. This alignment issue has also given rise to hybrid methods [4][5][6], in which near-body unstructured-grid solutions are interpolated to shockaligned structured-grid methods to increase accuracy.…”

mentioning

confidence: 99%

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Validation of an Output-Adaptive, Tetrahedral Cut-Cell Method for Sonic Boom Prediction

Park

Darmofal

2010

AIAA Journal

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A cut-cell approach to computational fluid dynamics that uses the median dual of a tetrahedral background grid is described. The discrete adjoint is also calculated for an adaptive method to control error in a specified output. The adaptive method is applied to sonic boom prediction by specifying an integral of offbody pressure signature as the output. These predicted signatures are compared to wind-tunnel measurements to validate the method for sonic boom prediction. Accurate midfield sonic boom pressure signatures are calculated with the Euler equations without the use of hybrid grid or signature propagation methods. Highly refined, shock-aligned anisotropic grids are produced by this method from coarse isotropic grids created without prior knowledge of shock locations. A heuristic reconstruction limiter provides stable flow and adjoint solution schemes while producing similar signatures to Barth-Jespersen and Venkatakrishnan limiters. The use of cut cells with an output-based adaptive scheme automates the volume grid generation task after a triangular mesh is generated for the cut surface.

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Section: A Double-cone Cylindermentioning

confidence: 99%

mentioning

confidence: 99%

Validation of an Output-Adaptive, Tetrahedral Cut-Cell Method for Sonic Boom Prediction

Park

Darmofal

2010

AIAA Journal

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“…Cheung et al[16] already in the nineties proposed the use of parabolized Navier-Stokes equations to predict the mid flow-field pointing out the expensive computational cost. CFD computations using Euler and full-potential equations to the far field evaluation and mesh adaptation have been evaluated on simple configurations by Kandil et al[17]. Despite the continuous increase in computational power, a brute force complete CFD evaluation for real aircraft geometry is still challenging and appears useless if no counter-measures based on mesh adaptation are taken into account.…”

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confidence: 99%

Meta-model-assisted MGDA for multi-objective functional optimization

et al. 2014

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International audienceA novel numerical method for multi-objective differentiable optimization, the Multiple-Gradient Descent Algorithmm (MGDA), has been proposed in [8] [11] to identify Pareto fronts. In MGDA, a direction of search for which the directional gradients of the objective functions are all negative, and often equal by construction [12], is identified and used in a steepest-descent-type iteration. The method converges to Pareto-optimal points. MGDA is here briefly reviewed to outline its principal theoretical properties and applied first to a classical mathematical test-case for illustration. The method is then ex-tended encompass cases where the functional gradients are approximated via meta-models, as it is often the case in complex situations, and demonstrated on three optimum-shape design problems in compressible aerodynamics.The first problem is purely related to aerodynamic performance. It is a wing shape optimization exercise w.r.t. lift and drag in typical transonic cruis

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“…This configuration has also been used by other researchers to evaluate their signature prediction techniques. 12,15 The pressure integral output function was defined as a cylinder, six body lengths in radius, centered about the geometry axis. The cylinder is clipped forward of 3 body lengths behind the nose, aft of 9 body lengths behind the nose, and outside of 0.1 body lengths off the centerline to focus only on the region where wind tunnel data is available.…”

Section: Via Cone-cylinder Configurationmentioning

confidence: 99%

“…To improve alignment, isotropic unstructured grids are stretched to align the tetrahedra with the free stream Mach angle to improve signal propagation for initial grids. 10 This alignment issue has also given rise to hybrid methods [11][12][13] where near-body unstructured grid solutions are interpolated to shock-aligned structured grid methods to increase accuracy. The hybrid methods are hindered by the interpolation process, so adaptive grid methods 14,15 are employed to improve the accuracy of unstructured grid methods for long propagation distances.…”

mentioning

confidence: 99%

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

Park¹,

Darmofal

2008

26th AIAA Applied Aerodynamics Conference

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A cut-cell approach to Computational Fluid Dynamics (CFD) that utilizes the median dual of a tetrahedral background grid is described. The discrete adjoint is also calculated, which permits adaptation based on improving the calculation of a specified output (off-body pressure signature) in supersonic inviscid flow. These predicted signatures are compared to wind tunnel measurements on and off the configuration centerline 10 body lengths below the model to validate the method for sonic boom prediction. Accurate mid-field sonic boom pressure signatures are calculated with the Euler equations without the use of hybrid grid or signature propagation methods. Highly-refined, shock-aligned anisotropic grids were produced by this method from coarse isotropic grids created without prior knowledge of shock locations. A heuristic reconstruction limiter provided stable flow and adjoint solution schemes while producing similar signatures to Barth-Jespersen and Venkatakrishnan limiters. The use of cut-cells with an output-based adaptive scheme completely automated this accurate prediction capability after a triangular mesh is generated for the cut surface. This automation drastically reduces the manual intervention required by existing methods.

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Sonic Boom Computations for Double-Cone Configuration Using CFL3D, FUN3D and Full-Potential Codes

Cited by 7 publications

References 4 publications

Validation of an Output-Adaptive, Tetrahedral Cut-Cell Method for Sonic Boom Prediction

Validation of an Output-Adaptive, Tetrahedral Cut-Cell Method for Sonic Boom Prediction

Meta-model-assisted MGDA for multi-objective functional optimization

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

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