Recent Developments on the Turbulence Modeling Resource Website (Invited)

Rumsey, Christopher L.

doi:10.2514/6.2015-2927

Cited by 33 publications

(32 citation statements)

References 28 publications

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“…In the first place, the in-house code was verified against established CFD codes such as CFL3D, FUN3D and OVERFLOW [17,24]. The verification cases include a square duct, an axisymmetric bump and a backward-facing step, as illustrated in Fig.1.…”

Section: Flow Solver Validation and Verificationmentioning

confidence: 99%

“…In this paper, the state-of-the-art modified SA models are evaluated for a transonic fan rotor, which is of contemporary design interest but has been seldom addressed in previous works. These modified SA models include the one with a quadratic constitutive relation (SA-QCR) [15] and one with rotation and curvature correction (SA-RC) [16], both of which have been widely implemented in several computational fluid dynamics (CFD) solvers and tested in a broad range of cases (i.e., reaching model readiness rating level 3 [17]). In addition, emerging modifications using helicity (SA-H) [18] and pressure gradient (SA-PG) [19] are also evaluated since they were found useful in fan rotor stall prediction [20,21].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of Spalart-Allmaras Turbulence Model Forms for a Transonic Axial Compressor

He¹,

Zhao²,

Vahdati³

2020

Proceedings of Global Power &Amp; Propulsion Society

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A comparative study of the state-of-the-art modified Spalart-Allmaras (SA) model forms has been conducted on the transonic axial compressor NASA Rotor 67. The models studied include the SA-QCR model that improves the Boussinesq assumption, the SA-RC model that tunes turbulence production considering rotation and curvature, the SA-H model that enhances turbulence source using helicity, and the SA-PG model that boosts turbulence source using adverse pressure gradient. By comparing the results in performance characteristics and radial, circumferential and chordwise profiles, the original SA model is found to over-predict the tip blockage size and thus cause large discrepancies in the near-stall performance. The SA-QCR and SA-RC models show limited effects on the tip blockage and the near-stall performance, whereas the SA-H and SA-PG models show improved predictions, although still not near perfection. The findings suggest the requirement of a new model for better prediction of compressor tip blockage.

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Section: Flow Solver Validation and Verificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of Spalart-Allmaras Turbulence Model Forms for a Transonic Axial Compressor

He¹,

Zhao²,

Vahdati³

2020

Proceedings of Global Power &Amp; Propulsion Society

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“…Establishing sonic boom prediction benchmark cases in the form of the Turbulence Modeling Resource Website [78,79] is advocated by the participants. The SBPW1 and SBPW2 data sets are available and could form a critical mass of models and test cases.…”

Section: Recommendations and Next Stepsmentioning

confidence: 99%

Nearfield Summary and Statistical Analysis of the Second AIAA Sonic Boom Prediction Workshop

Park

Nemec

2019

Journal of Aircraft

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A summary is provided for the Second AIAA Sonic Boom Workshop held 8-9 January 2017 in conjunction with AIAA SciTech 2017. The workshop used three required models of increasing complexity: an axisymmetric body, a wing body, and a complete configuration with flow-through nacelle. An optional complete configuration with propulsion boundary conditions is also provided. These models are designed with similar nearfield signatures to isolate geometry and shock/expansion interaction effects. Eleven international participant groups submitted nearfield signatures with forces, pitching moment, and iterative convergence norms. Statistics and grid convergence of these nearfield signatures are presented. These submissions are propagated to the ground, and noise levels are computed. This allows the grid convergence and the statistical distribution of a noise level to be computed. While progress is documented since the first workshop, improvement to the analysis methods for a possible subsequent workshop are provided. The complete configuration with flow-through nacelle showed the most dramatic improvement between the two workshops. The current workshop cases are more relevant to vehicles with lower loudness and have the potential for lower annoyance than the first workshop cases. The models for this workshop with quieter ground noise levels than the first workshop exposed weaknesses in analysis, particularly in convective discretization. * Research Scientist, Computational AeroSciences Branch, Mike.Park@NASA.gov, AIAA Senior Member. † Aerospace Engineer, Computational Aerosciences Branch, Marian.Nemec@NASA.gov, AIAA Senior Member.

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“…This evaluation includes 2D test cases [5] and 3D test cases [6]. This effort uses a set of 3D test cases described on the Turbulence Modeling Resource (TMR) Website [7] as 3D Hemisphere Cylinder (new) and 3D ONERA M6 Wing with the Spalart-Allmaras (SA) turbulence model [8].…”

Section: Introductionmentioning

confidence: 99%

Unstructured Grid Adaptation and Solver Technology for Turbulent Flows

Park

Barral

Ibanez

et al. 2018

2018 AIAA Aerospace Sciences Meeting

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Unstructured grid adaptation is a tool to control Computational Fluid Dynamics (CFD) discretization error. However, adaptive grid techniques have made limited impact on production analysis workflows where the control of discretization error is critical to obtaining reliable simulation results. Issues that prevent the use of adaptive grid methods are identified by applying unstructured grid adaptation methods to a series of benchmark cases. Once identified, these challenges to existing adaptive workflows can be addressed. Unstructured grid adaptation is evaluated for test cases described on the Turbulence Modeling Resource (TMR) web site, which documents uniform grid refinement of multiple schemes. The cases are turbulent flow over a Hemisphere Cylinder and an ONERA M6 Wing. Adaptive grid force and moment trajectories are shown for three integrated grid adaptation processes with Mach interpolation control and output error based metrics. The integrated grid adaptation process with a finite element (FE) discretization produced results consistent with uniform grid refinement of fixed grids. The integrated grid adaptation processes with finite volume schemes were slower to converge to the reference solution than the FE method. Metric conformity is documented on grid/metric snapshots for five grid adaptation mechanics implementations. These tools produce anisotropic boundary conforming grids requested by the adaptation process.

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Recent Developments on the Turbulence Modeling Resource Website (Invited)

Cited by 33 publications

References 28 publications

Evaluation of Spalart-Allmaras Turbulence Model Forms for a Transonic Axial Compressor

Evaluation of Spalart-Allmaras Turbulence Model Forms for a Transonic Axial Compressor

Nearfield Summary and Statistical Analysis of the Second AIAA Sonic Boom Prediction Workshop

Unstructured Grid Adaptation and Solver Technology for Turbulent Flows

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