Best Practices in Overset Grid Generation

Gomez, Reynaldo J.

doi:10.2514/6.2002-3191

Cited by 168 publications

(50 citation statements)

References 27 publications

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“…Moreover, meshed surfaces are assembled in groups in order to assign boundary conditions (see Figure 10): an Euler boundary condition on the wing, a far-field condition on the computational domain boundaries, and a symmetry condition on the symmetry plane. The computational domain used for the numerical analysis is a large parallelepiped and the far-field boundary is located around 20 body lengths away from the airplane (Figure 10), as suggested by Chan et al 32 Regions characterized by higher curvature, like the wing leading edge and trailing edge have a higher grid refinement. Close to leading edge, the element size of the surface grid is ∼0.1% of the local chord length.…”

Section: Figure 9 Aerodynamic Analysis Modulementioning

confidence: 99%

Aerodynamic Design of a Flying V Aircraft

Faggiano

Vos

Baan³

et al. 2017

17th AIAA Aviation Technology, Integration, and Operations Conference

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A Flying V aircraft is a tailless, V-shaped flying wing with two cylindrical pressurized cabins placed in the wing leading edge and two over-the-wing engines. Elevons provide longitudinal and lateral control while two tip-mounted vertical tails double as winglets. The goal of the presented study is to estimate the lift-to-drag ratio of this configuration at the cruise condition: M = 0.85, h = 13, 000m, and CL = 0.26. A vortex-lattice method is used to rapidly investigate the feasible design space, whereas an Euler solver on an unstructured grid is adopted for a more accurate wave and vortex-induced drag estimation. The profile drag is computed by an empirical method. The NASA Common Research Model is adopted as a benchmark with an estimated lift-to-drag ratio of 18.9. The three-dimensional geometry of the Flying V is generated according to a multi-level parametrization: the planform shape is parametrized with 10 variables, five wing sections are identified and described by a total of 43 parameters, while the winglet planform is defined by 3 additional variables. After a multi-fidelity design space exploration, two design approaches are investigated: a dual-step optimization, where planform and airfoil variables are subsequently varied, and a single-step optimization, where planform and airfoil variables are varied simultaneously. The highest lift-to-drag ratio is attained with the single-step optimized configuration and amounts to 23.7. It is therefore concluded that the Flying V Aircraft can have a 25% higher lift-to-drag ratio than the reference aircraft.

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Section: Figure 9 Aerodynamic Analysis Modulementioning

confidence: 99%

Aerodynamic Design of a Flying V Aircraft

Faggiano

Vos

Baan³

et al. 2017

17th AIAA Aviation Technology, Integration, and Operations Conference

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“…25 It uses a finite-difference formulation with flow quantities stored at the grid nodes. OVERFLOW has central-and Roe upwind-difference options, and uses a diagonalized, implicit approximate factorization scheme for time advancement.…”

Section: A Code Descriptionmentioning

confidence: 99%

Assessment of Turbulent Shock-Boundary Layer Interaction Computations Using the OVERFLOW Code

Oliver

Lillard

Schwing

et al. 2007

45th AIAA Aerospace Sciences Meeting and Exhibit

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The performance of two popular turbulence models, the Spalart-Allmaras model and Menter's SST model, and one relatively new model, Olsen & Coakley's Lag model, are evaluated using the OVERFLOW code. Turbulent shock-boundary layer interaction predictions are evaluated with three different experimental datasets: a series of 2D compression ramps at Mach 2.87, a series of 2D compression ramps at Mach 2.94, and an axisymmetric coneflare at Mach 11. The experimental datasets include flows with no separation, moderate separation, and significant separation, and use several different experimental measurement techniques (including laser doppler velocimetry (LDV), pitot-probe measurement, inclined hot-wire probe measurement, preston tube skin friction measurement, and surface pressure measurement). Additionally, the OVERFLOW solutions are compared to the solutions of a second CFD code, DPLR. The predictions for weak shock-boundary layer interactions are in reasonable agreement with the experimental data. For strong shock-boundary layer interactions, all of the turbulence models overpredict the separation size and fail to predict the correct skin friction recovery distribution. In most cases, surface pressure predictions show too much upstream influence, however including the tunnel side-wall boundary layers in the computation improves the separation predictions.

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“…3 Overset grid capability makes OVERFLOW ideal for predicting flowfields over very complex geometries. Olsen et al 4 verified the applicability of the OVERLFOW code to hypersonic flowfields by looking at several inviscid and viscous flowfields.…”

Section: Introductionmentioning

confidence: 99%

Laminar Heating Validation of the OVERFLOW Code

Lillard

Dries

2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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OVERFLOW, a structured finite difference code, was applied to the solution of hypersonic laminar flow over several configurations assuming perfect gas chemistry. By testing OVERFLOW's capabilities over several configurations encompassing a variety of flow physics a validated laminar heating was produced. Configurations tested were a flat plate at 0 degrees incidence, a sphere, a compression ramp, and the X-38 re-entry vehicle. This variety of test cases shows the ability of the code to predict boundary layer flow, stagnation heating, laminar separation with re-attachment heating, and complex flow over a three-dimensional body. In addition, grid resolutions studies were done to give recommendations for the correct number of off-body points to be applied to generic problems and for wall-spacing values to capture heat transfer and skin friction. Numerical results show good comparison to the test data for all the configurations.

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Best Practices in Overset Grid Generation

Abstract: Grid generation for overset grids on complex geom-

Cited by 168 publications

References 27 publications

Aerodynamic Design of a Flying V Aircraft

Aerodynamic Design of a Flying V Aircraft

Assessment of Turbulent Shock-Boundary Layer Interaction Computations Using the OVERFLOW Code

Laminar Heating Validation of the OVERFLOW Code

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