UNS3D Simulations for the Third Sonic Boom Prediction Workshop Part II: C608 Low-Boom Flight Demonstrator

Carpenter, Forrest L.; Cizmas, Paul G. A.

doi:10.2514/6.2020-2733

Cited by 11 publications

(3 citation statements)

References 23 publications

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“…We ensure the quality of each simulation by checking iterative convergence of the numerical residual as well as mesh convergence of the objective function and adjoint-based error estimates, all shown in Fig. 15. Because of more complex geometry and initial coarse mesh, the functional may not be entirely monotonic; initially, small features are not well resolved and there is not enough mesh resolution for the signal to reach the farthest radial line sensors without excessive dissipation.…”

Section: Case Ii: C608 Full Aircraft Geometrymentioning

confidence: 99%

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Cartesian Mesh Simulations for the Third AIAA Sonic Boom Prediction Workshop

Spurlock

Aftosmis

Nemec

2022

Journal of Aircraft

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Simulation results are presented for all cases from the Third AIAA Sonic Boom Prediction Workshop. An inviscid, embedded-boundary Cartesian-mesh flow solver is used in conjunction with adjoint-based mesh adaptation to compute near-field pressure signatures. Specialized techniques are applied to maximize accuracy and minimize cost on Cartesian meshes. Regions of the flow most sensitive to discretization error are identified using Richardson extrapolation. Timing results and mesh sizes for near-field cases demonstrate that decomposition into multiple offtrack simulations is efficient in both computational time and wall-clock time, with results among the least computationally expensive of those presented at the workshop. Pressure signals are propagated to the ground using an augmented Burgers equation solver to predict boom carpets. Ground signatures and loudness metrics are presented for a standard atmosphere as well as an atmosphere with wind profiles that affect overall noise levels and can significantly widen the boom carpet. Mesh convergence studies show that high sampling frequencies, around 500 kHz, are required for on-track propagation; the sampling frequency increases at large off-track angles due to longer acoustic ray paths. Overall, the approach presented here yields accurate results for predicting low-sonic-boom signatures.

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Section: Case Ii: C608 Full Aircraft Geometrymentioning

confidence: 99%

“…These workshops bring together participants with many different approaches and simulation tools to compare results and identify challenges for further research. Additional SBPW3 results and summaries highlight the near-field [7][8][9][10][11][12][13][14][15] and propagation [16][17][18][19] portions of the workshop.…”

mentioning

confidence: 98%

Cartesian Mesh Simulations for the Third AIAA Sonic Boom Prediction Workshop

Spurlock

Aftosmis

Nemec

2022

Journal of Aircraft

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“…There are two conditions that must be satisfied with symmetry boundaries: no-penetration and the zero-gradient of state variables on the planes of symmetry. For this paper, a strong implementation of the zero-gradient condition was enforced, that is, both the boundary state vectors and state vectors on the symmetry boundary had the zero-gradient condition applied [18].…”

Section: Flow Boundary Conditionsmentioning

confidence: 99%

Several Cases for the Validation of Turbulence Models Implementation

Polewski

Cizmas

2021

Applied Sciences

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This paper presents several test cases that were used to validate the implementation of two turbulence models in the UNS3D code, an in-house code. The two turbulence models used were the Shear Stress Transport model and the Spalart–Allmaras model. These turbulence models were explored using the numerical results generated by three computational fluid dynamics codes: NASA’s FUN3D and CFL3D, and UNS3D. Four cases were considered: a flat plate case, an airfoil near-wake, a backward-facing step, and a turbine cascade known as the Eleventh Standard Configuration. The numerical results were compared among themselves and against experimental data.

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