CFD Validation for High-Lift Devices: Two-Element Airfoil

Murayama, Mitsuhiro; Zhong, Lei; Mukai, Junichi; Yamamoto, Kazuomi

doi:10.2322/tjsass.49.31

Cited by 11 publications

(9 citation statements)

References 19 publications

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“…In this study, three turbulence models, Spalart-Allmaras one-equation model (SA), 11) Lander-Sharma k-" two-equation model (LS k-"), 12) and Menter's shear stress transport two-equation model (SST), 13) are used to simulate turbulent flows. In our companion paper, 4) the Abid k-" two-equation model is used as a k-" type turbulence model. However, the model can show a delay in transition by the strong pressure gradient on the slat.…”

Section: Flow Solver and Turbulence Modelmentioning

confidence: 99%

“…Flows around high-lift devices have large circulation and wake, so the location of the outer boundary has a large influence; especially on the accuracy of drag prediction, as discussed in Murayama and Yamamoto 3) and Lei, Murayama, Takenaka and Yamamoto. 4) In such computations, a correction of the outer boundary conditions or a large computational domain is required. In the ADCS code, a vortex correction 17) is applied at the outer boundary, which is located 50-chord lengths away from the airfoil.…”

Section: Computational Conditions and Meshesmentioning

confidence: 99%

“…Computational comparisons of a basic two-element airfoil (main element and flap) are given separately in a companion paper. 4) In this paper, we focus on a more complex high-lift device comprising three elements (i.e., a slat, a main wing and a flap). First, the results of two structured mesh CFD codes and an unstructured mesh CFD code using the same turbulence model are compared and discussed.…”

Section: Introductionmentioning

confidence: 99%

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CFD Validation for High-Lift Devices: Three-Element Airfoil

Murayama

Zhong

Mukai

et al. 2006

Trans. Japan Soc. Aero. S Sci.

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In this study, the accuracy of structured and unstructured mesh CFD codes in simulating the flow around a threeelement high-lift configuration (slat, main wing, and flap) is assessed, and mesh dependency and effect of turbulence models are studied. In the first part of the study, the results of two structured mesh CFD codes and an unstructured mesh CFD code using the same turbulence model are compared and discussed. A mesh refinement approach is also used to examine the dependency of numerical accuracy on the density of unstructured meshes. By properly distributing mesh points in an unstructured mesh, the detail in flow physics is obtained. It is also shown that the quantitative prediction of the vortex in the slat cove is an important factor that affects accuracy. In the second part of the study, three turbulence models are compared using one of the structured mesh CFD codes. All turbulence models can produce similar flowfields. However, several differences are seen in the separated regions, especially in the slat cove. Commonly used turbulence models, Spalart-Allmaras model and Menter's SST model, produce similar aerodynamic forces at lower angles of attack. At higher angles of attack, the SST model gives better results for the present computations. It is found that the maximum lift and the angle at which the stall occurs are very sensitive to the turbulence model.

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Section: Flow Solver and Turbulence Modelmentioning

confidence: 99%

Section: Computational Conditions and Meshesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CFD Validation for High-Lift Devices: Three-Element Airfoil

Murayama

Zhong

Mukai

et al. 2006

Trans. Japan Soc. Aero. S Sci.

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“…Flows around high-lift devices have large circulation and wake, so that the location of the outer boundary has a large influence, especially concerning drag prediction, as discussed in Ref. 24. Such computations require either a correction of the outer boundary conditions or a large computational domain.…”

Section: Computational Resultsmentioning

confidence: 98%

Validation of Computations Around High-Lift Configurations by Structured- and Unstructured-Mesh

Murayama

Yamamoto

Kobayashi

2006

Journal of Aircraft

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In this study, flow computations are performed on two-dimensional and three-dimensional high-lift configurations on multiblock structured and unstructured meshes. The objectives are to assess and improve the reliability in simulating the flow around such devices. First, two-dimensional computations on two-element and three-element airfoils are performed to investigate mesh dependency in detail. For unstructured meshes, this is carried out by using a mesh-refinement approach. The results show that sufficient mesh density away from the wing surface is required for accurate drag prediction because the flow has large circulation and wake. A mesh-refinement approach using entropy increment as the refinement indicator is also applied, and its effectiveness is validated. The method is effective in increasing the mesh points in the region of physical importance, such as wake, and the region where the numerical error is high. Three-dimensional computations on three-element trapezoidal wings with fuselage are also performed, and some modest grid studies are performed with structured meshes. Two configurations with full-span flap and part-span flap are used. Ways to improve the reliability of structured and unstructured meshes are discussed by comparing the results. The prediction of aerodynamic forces is quite reasonable even on the unstructured mesh at moderate settings of slat and flap, despite minor differences in local flow physics. However, it is also shown that the unstructured meshes should be further refined to resolve the wake near trailing edge, wing-tip vortices, and the flow separation at the juncture of the wing and body for more accurate prediction.

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“…The aerodynamic forces were predicted reasonably, even with the unstructured mesh when moderate settings for the slat and flap were used [7].…”

Section: Numerical Analysismentioning

confidence: 93%

Grid Discretization Study for the Efficient Aerodynamic Analysis of the Very Light Aircraft (VLA) Configuration

Sitio¹,

Kim²,

Lee³

2013

International Journal of Aeronautical and Space Sciences

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In this research the development of unstructured grid discretization solution techniques is presented. The purpose is to describe such a conservative discretization scheme applied for experimental validation work. The objective of this paper is to better establish the effects of mesh generation techniques on velocity fields and particle deposition patterns to determine the optimal aerodynamic characteristics.In order to achieve the objective, the mesh surface discretization approaches used the VLA prototype manufacturing tolerance zone of the outer surface. There were 3 schemes for this discretization study implementation. They are solver validation, grid convergence study and surface tolerance study.A solver validation work was implemented for the simple 2D and 3D model to get the optimum solver for the VLA model. A grid convergence study was also conducted with a different growth factor and cell spacing, the amount of mesh can be controlled. With several amount of mesh we can get the converged amount of mesh compared to experimental data. The density around surface model can be calculated by controlling the number of element in every important and sensitive surface area of the model.The solver validation work result provided the optimum solver to employ in the VLA model analysis calculation. The convergence study approach result indicated that the aerodynamic trend characteristic was captured smooth enough compared with the experimental data. During the surface tolerance scheme, it could catch the aerodynamics data of the experiment data. The discretization studies made the validation work more efficient way to achieve the purpose of this paper.

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CFD Validation for High-Lift Devices: Two-Element Airfoil

Cited by 11 publications

References 19 publications

CFD Validation for High-Lift Devices: Three-Element Airfoil

CFD Validation for High-Lift Devices: Three-Element Airfoil

Validation of Computations Around High-Lift Configurations by Structured- and Unstructured-Mesh

Grid Discretization Study for the Efficient Aerodynamic Analysis of the Very Light Aircraft (VLA) Configuration

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