A Solution-Based Adaptive Redistribution Method for Unstructured Meshes

Ito, Yasushi; Shih, Alan M.; Koomullil, Roy P.; Soni, Bharat K.

doi:10.1007/978-3-540-34958-7_9

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…Consider a source defined at a point in the domain p, then the spacing s at an arbitrary point x is s ( s 0 : r < r 1 s 0 1 r−r 1 r 2 −r 1 : r > r 1 (2) in which r kx − pk, and s 0 is the spacing value applied at the center of the source. The spacing will decay linearly after a certain distance, and the rate of decay is such that the mesh spacing has doubled at the distance r 2 .…”

Section: A Feature-aligned Surface Meshesmentioning

confidence: 99%

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Geometric Representation of Flow Features Using the Medial Axis for Mesh Generation

Harris

Qin

2015

AIAA Journal

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A method to represent complex flow features as geometric entities, using the medial axis for the purpose of generating flow-feature aligned meshes, is presented. These geometric entities are embedded into the domain to influence the generation of unstructured quad-dominant surface meshes in two and three dimensions. The resulting high-quality feature-aligned surface meshes can locally mimic the attributes of a structured grid. This paper also presents a method to extrude shock-aligned quad-dominant surface meshes beyond the boundary layer to cover the extent of transonic shock waves. The process provides a means to embed a high-quality hex-dominant mesh block, aligned with the transonic shock wave, into a hybrid volume mesh for viscous computations. Inclusion of the aligned mesh block is shown to enhance the ability of the hybrid mesh to resolve the shock wave, and thus, improve the numerical solution.Nomenclature a = speed of sound M n = normal Mach number R 2 = polynomial-fit-quality measure r 1 , r 2 = background-source radii of influence S = point set s, s 0 = background-source mesh-spacing values V = velocity vector α = radius size in α-shape computation β = angle between neighboring medial-axis branches ∇p = pressure gradient

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Section: A Feature-aligned Surface Meshesmentioning

confidence: 99%

“…A number of these methods involve the representation of solution features such as shock waves or wakes as geometric entities [1][2][3][4][5]. These entities can be embedded within the solution domain to influence how the mesh is formed in certain regions when it is regenerated.…”

Section: Introductionmentioning

confidence: 99%

Geometric Representation of Flow Features Using the Medial Axis for Mesh Generation

Harris

Qin

2015

AIAA Journal

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“…First, an isosurface is calculated at a normalized Mach number of 0.99 (Figure 5(a)). To remove small features, least‐square fitting is applied to the isosurface 8, and two cones are obtained (Figure 5(b)). The cone surfaces are trimmed so that they do not intersect with the ogive geometry and so that they properly intersect with the outlet plane (indicated by gray in Figure 5(c)).…”

Section: Applicationsmentioning

confidence: 99%

Hybrid mesh generation with embedded surfaces using a multiple marching direction approach

Ito

Shih

Soni

2011

Numerical Methods in Fluids

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SUMMARYThis paper proposes a method for the creation of hybrid meshes with embedded surfaces for viscous flow simulations as an extension of the multiple marching direction approach (AIAA J. 2007; 45(1):162-167). The multiple marching direction approach enables to place semi-structured elements around singular points, where valid semi-structured elements cannot be placed using conventional hybrid mesh generation methods. This feature is discussed first with a couple of examples. Elements sometimes need to be clustered inside a computational domain to obtain more accurate results. For example, solution features, such as shocks, vortex cores and wake regions, can be extracted during the process of adaptive mesh generation. These features can be represented as surface meshes embedded in a computational domain. Semi-structured elements can be placed around the embedded surface meshes using the multiple marching direction approach with a pretreatment method. Tetrahedral elements can be placed easily instead. A couple of results are presented to demonstrate the capability of the mesh generation method.

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“…The research team in the Sandia National Laboratory has implemented several hexahedral mesh generation algorithms in the CUBIT software including paving (Blacker and Stephenson 1991), mapping (Tautges, Liu, Lu, Kraftcheck, and Gadh 1997), plastering (Staten, Owen, and Blacker 2005) and special purpose primitives. Other methods in generating hexahedral meshes have also been created: medial axis (Ito, Shih, Koomullil, and Soni 2006), grid based ( (Zhang, Bajaj, and Xu 2009) and (Marechal 2009)) and Whisker Weaving (Ito, Shih, Koomullil, and Soni 2007). The algorithm in this paper will generate uniform all-hexahedral and adaptive hexahedral-dominant mesh.…”

Section: Hexahedral Mesh Generationmentioning

confidence: 99%

Conformal adaptive hexahedral-dominant mesh generation for CFD simulation in architectural design applications

Zhang¹,

Lam²

2011

Proceedings of the 2011 Winter Simulation Conference (WSC)

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Mesh generation is a critical and probably the most manually intensive step in CFD simulations in the architectural domain. One essential feature is the large span of dimensional scales that is encountered in design, particularly if the model aims to simulate indoor and outdoor conditions concurrently, e.g., site at the magnitude of kilometers while building elements at the magnitude of centimeters. In addressing the challenge this paper presents an approach to generate adaptive hexahedral-dominate meshes for CFD simulations in sustainable architectural design applications. Uniform all-hexahedral meshes and adaptive hexahedral-dominant meshes are both generated for natural ventilation simulation of a proposed retrofit building in Philadelphia. Simulation results show that adaptive hexahedral-dominate meshes generate very similar results of air change rate in the space due to natural ventilation, compared to all-hexahedral meshes yet with up to 90% reduction in number of elements in the domain, hence improve computation efficiency.

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A Solution-Based Adaptive Redistribution Method for Unstructured Meshes

Cited by 8 publications

References 19 publications

Geometric Representation of Flow Features Using the Medial Axis for Mesh Generation

Geometric Representation of Flow Features Using the Medial Axis for Mesh Generation

Hybrid mesh generation with embedded surfaces using a multiple marching direction approach

Conformal adaptive hexahedral-dominant mesh generation for CFD simulation in architectural design applications

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