Boundary layer mesh generation for viscous flow simulations

Garimella, Rao V.; Shephard, Mark S.

doi:10.1002/1097-0207(20000910/20)49:1/2<193::aid-nme929>3.0.co;2-r

Cited by 112 publications

(61 citation statements)

References 20 publications

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“…Figure 3 shows the dark gray layer as an extrusion of the unstructured light gray surface mesh. A simplified implementation of a generalized advancing layer technique is used to create the prismatic elements [8]. In the following a vertex positioned on a G 2 entity is called ordinary vertex and a vertex located at a G 1 or G 0 entity is called either sliding or fixed vertex.…”

Section: Prismatic Layermentioning

confidence: 99%

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Sensitivity Study of the Numerical Setup for an Automatic Optimization Procedure for a Hydraulic Machine

Tismer¹,

Schlipf²,

Riedelbauch³

2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Abstract. For an automatic optimization using Computational Fluid Dynamics, all design iterations of a turbo-machine require the generation of geometry and computational mesh as well as the simulation of the flow and the evaluation of one or more characteristic properties. All steps can be expensive regarding time or manpower. In addition, all meshes of the design iterations differ in total number of cells, percentage of a particular element type, local refinement sections or structured mesh block thickness being summarized as mesh characteristics. An object-oriented framework focused on hydraulic machinery is used to generate different geometry variants. Furthermore, the framework is extended to create hybrid meshes consisting of a structured part surrounding the blades and an unstructured part within the remaining flow channel. The structured-unstructured mesh coupling is realized with the Pyramid Open Method. In order to take care of the boundary layer flow effects along the meridional contour upstream and downstream of the runner blade rows a prismatic layer creation algorithm is also implemented. OpenFOAM software is applied to simulate the flow through the hydraulic machine. Each step in the process chain is implemented as part of the framework. The complete study is done using open source applications, libraries and tools. In terms of performing an automatic optimization procedure an assessment for the numerical behavior of the hybrid mesh in a real-engineering application is desired. To limit the number of optimization parameters and the amount of computation time the sensitivity analysis tool supports the identification of relevant geometry input parameters with significant influence on the flow field. On the one hand it is important to discover the influence of geometry variations on the predicted physical behavior (e.g. flow losses, torque and head) of the simulation results. On the other hand it is investigated if the uncontrollable changes of mesh characteristics or user controlled numerical discretization parameters, such as flux gradients affect the physical quantities on the same level as the geometric variations. The goal is to achieve a dominating geometry influence and a minor effect of mesh characteristics on the predicted flow field solution. For both, a typical Francis and a Propeller turbine runner, the fluctuations and absolute values of physical properties are shown for a number of varying meshes, numerical and geometrical setup parameters.

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Section: Prismatic Layermentioning

confidence: 99%

“…It is important to mention that the simplified algorithm in the framework does not provide all features mentioned in [8]. Caused by the predefined transfinite layers, it is not necessary to calculate multiple growth curves of mesh vertices.…”

Section: Prismatic Layermentioning

confidence: 99%

Sensitivity Study of the Numerical Setup for an Automatic Optimization Procedure for a Hydraulic Machine

Tismer¹,

Schlipf²,

Riedelbauch³

2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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“…A common method to construct boundary layer meshes, referred to as the advancing layers method [12,15,17], inflates the unstructured surface mesh on no-slip walls, where boundary layers form. This inflation is done into the volume, along the local surface normals as a structured stack of layers, up to a specified distance and fills the rest of the domain with unstructured elements.…”

Section: Meshes With Boundary Layersmentioning

confidence: 99%

“…In these regions carefully constructed boundary layers that consider the physics of the flow and the abilities of the flow models used result in the most effective means to construct the local portions of the mesh [11][12][13][14]. The best method of construction of such boundary layer meshes is to decompose the mesh in an unstructured mesh in the "plane of the surface" and a graded and structured mesh in the normal direction [11,12,[15][16][17]. Layered structure of elements in boundary layer meshes near no-slip walls plays a critical role.…”

Section: Introductionmentioning

confidence: 99%

Parallel Adaptive Boundary Layer Meshing for CFD Analysis

Ovcharenko

Chitale

Sahni

et al. 2013

Proceedings of the 21st International Meshing Roundtable

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Summary. This paper describes a parallel procedure for anisotropic mesh adaptation with boundary layers for use in scalable CFD simulations. The parallel mesh adaptation algorithm operates with local mesh modification operations developed for both unstructured and boundary layer parts of the mesh. The adaptive approach maintains layered elements near the viscous walls and accounts for the mesh modification operations that are carried out in parallel on a distributed mesh. In the process mesh relationships and approximations with respect to curved complex 3D geometries of interest are properly maintained. The parallel mesh adaptation procedures are applied to two problems: a heat transfer manifold and a scramjet engine.

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“…Criteria chosen and algorithmic modifications make use of similar principles as in earlier work [12][13][14], but are adapted for the specific requirements of mesh generation for aircraft configurations. An existing set of open-source tools is exploited for mesh data structures, file format support, surface mesh generation and the creation of tetrahedral volume meshes.…”

Section: Introductionmentioning

confidence: 99%

Implementation and evaluation of automated tetrahedral–prismatic mesh generation software

Eller¹,

Tomac²

2016

Computer-Aided Design

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An open-source implementation of an efficient mesh generation procedure for hybrid prismatic-tetrahedral meshes intended for use in Reynolds-averaged Navier-Stokes solutions is presented. The method employed combines the established, and very fast, Delaunay-based tetrahedral mesh generator TetGen with a novel technique for the creation of a prismatic layer, where constrained global optimization of the envelope is employed. Once a well-shaped envelope is thus obtained, a semi-structured layer of pentahedral elements is extruded between wall and envelope surface. Satisfactory mesh quality is demonstrated by comparing solutions obtained using the new meshes with reference data computed on high-quality advancing-front grids. Mesh generation time is shown to be substantially smaller than with many other methods. Overall, the presented implementation is deemed a valuable tool for cases where many meshes need to be generated for routine analyses and turnaround time is critical.

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Boundary layer mesh generation for viscous flow simulations

Cited by 112 publications

References 20 publications

Sensitivity Study of the Numerical Setup for an Automatic Optimization Procedure for a Hydraulic Machine

Sensitivity Study of the Numerical Setup for an Automatic Optimization Procedure for a Hydraulic Machine

Parallel Adaptive Boundary Layer Meshing for CFD Analysis

Implementation and evaluation of automated tetrahedral–prismatic mesh generation software

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