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This paper aims to simulate unsteady flows with surfaces in relative motion using a multi-block structured flow solver.

A procedure for simulating unsteady flows with surfaces in relative motion was developed, based upon a multi-block structured U-RANS flow solver1. Meshes produced in zones of the flow field with different rotation speed are connected by sliding boundaries. The procedure developed guarantees that the flux conservation properties of the original scheme are maintained across the sliding boundaries during the rotation at every time step.

The solver turns out to be very efficient, allowing computation in scalar mode with single core processors as well as in parallel. It was tested by simulating the unsteady flow on a propfan configuration with two counter-rotating rotors. The comparison of results and performances with respect to an existing commercial flow solver (unstructured) is reported.

This paper fulfils an identified need to allow for efficient unsteady flow computations (structured solver) with different bodies in relative motion.

In this work, a mortar method is implemented for tying arbitrary dissimilar 3D meshes, i.e. 3D meshes with curved, non‐matching interfaces. The 3D method requires approximations to the surface integrals specified by the projection of the displacement jump across the interface onto the Lagrange multiplier space. The numerical integration scheme is presented and several Lagrange multiplier interpolation schemes are considered. Furthermore, some implementational issues such as how to handle boundary conditions will be described such that stability is retained. Finally, the implementation will be demonstrated in numerical simulations and comparison of different formulations will be made.

Integrality of surface mesh is requisite for computational engineering. Nonwatertight meshes with holes can bring inconvenience to applications. Unlike simple modeling or visualization, the downstream industrial application scenarios put forward higher requirements for hole-filling, although many related algorithms have been developed. This study aims at the hole-filling issue in industrial application scenarios.

This algorithm overcomes some inherent weakness of general methods and generates a high-level resulting mesh. Initially, the primitive hole boundary is filled with a more appropriate triangulation which introduces fewer geometric errors. And in order for better performances on shape approximation of the background mesh, the algorithm also refines the initial triangulation with topology optimization. When obtaining the background mesh defining the geometry and size field, spheres on it are packed to determine the vertex configuration and then the resulting high-level mesh is generated.

Through emphasizing geometry recovery and mesh quality, the proposed algorithm works well in hole-filling in industrial application scenarios. Many experimental results demonstrate the reliability and the performance of the algorithm. And the processed meshes are capable of being used for industrial simulation computations directly.

This paper makes input meshes more adaptable for solving programs through local modifications on meshes and perfects the preprocessing technology of finite element analysis (FEA).

Contact detection for convex polygons/polyhedra has been a critical issue in discrete/discontinuous modelling, such as the discrete element method (DEM) and the discontinuous deformation analysis (DDA). The recently developed 3D contact theory for polyhedra in DDA depends on the so-called entrance block of two polyhedra and reduces the contact to evaluate the distance between the reference point to the corresponding entrance block, but effective implementation is still lacking.

In this paper, the equivalence of the entrance block and the Minkowski difference of two polyhedra is emphasised and two well-known Minkowski difference-based contact detection and overlap computation algorithms, GJK and expanding polytope algorithm (EPA), are chosen as the possible numerical approaches to the 3D contact theory for DDA, and also as alternatives for computing polyhedral contact features in DEM. The key algorithmic issues are outlined and their important features are highlighted.

Numerical examples indicate that the average number of updates required in GJK for polyhedral contact is around 6, and only 1 or 2 iterations are needed in EPA to find the overlap and all the relevant contact features when the overlap between polyhedra is small.

The equivalence of the entrance block in DDA and the Minkowski difference of two polyhedra is emphasised; GJK- and EPA-based contact algorithms are applied to convex polyhedra in DEM; energy conservation is guaranteed for the contact theory used; and numerical results demonstrate the effectiveness of the proposed methodologies.

This study aims to provide a novel method for sport places site selection, although instead of using decision-making methods, the focus is on analytic functions in geographic information systems (GIS).

Researchers today have combined site selection science to a large extent with GIS and different decision-making methods to provide methods with higher confidence coefficients, however, it seems that there is a long way left to the best result.

After making a study database including data related to uses and urban elements, sports places, population density in study territory and drawing map of the region, by exporting data to GIS environment this database was prepared to use as separate layers. In the next step, the final map was made by shared overlapping of layer resulted from combining determining factors in sport places site selection and a layer of the sphere of influence of sport places available.

As with other research studies done for site selection, the region determined as high value in the final map was wide, a method of minimizing the difference of maximum and minimum standard deviation of polygons was used to minimize these lands. This method made it possible to plan to construct multiple sport places in succession.

ETL format is a newly proposed CAD format, which is both simple enough that CAD models in this format can be easily sliced, and capable of describing solids with arbitrarily complex surface details. This paper aims to provide a method for slicing CAD models in ETL format.

The proposed slicing method is based on a method for slicing CAD models in colour STL format. Affine mapping method is used to calculate the colour of the intersection polygon of a voxel in the slicing result volume dataset, and a triangular facet that constitutes the geometry of the described object, when the facet has texture mapping definition.

The proposed slicing method is simple and robust. Implementations have demonstrated its feasibility.

The proposed slicing method is meaningful to preparing data for the rapid formation of models with complex surface details, including colour and textures.

A finite element mesh generator is described based on a conformal mapping which requires little more than the definition of boundary geometry to generate a mesh. The method is restricted to plane regions which are simply connected. The interior of a region containing a uniform mesh of regularly shaped 8‐node quadrilateral elements is mapped conformally to the physical domain with the result that bandwidth is automatically minimized and that smooth transitions are made between large and small elements. Although the procedure is not satisfactory for general applications, most common geometrical shapes can be modelled with meshes of good quality. The method is based primarily on boundary data but the user can specify a region of high mesh density. Examples are given to illustrate typical results.

The concept of the virtual reality library is introduced and defined as a new form of OPAC. Since a desktop virtual reality package is needed to construct a virtual reality library the expected functionality of such software is discussed in general terms. One such desktop virtual reality package, REND386, is then discussed in detail and used to build a working prototype of a virtual reality library.

The University of Michigan (U-M) is planning its course toward carbon neutrality. A key component in U-M carbon accounting is the calculation of carbon sinks via estimation of carbon storage and biosequestration on U-M landholdings. Here, this paper aims to compare multiple remote sensing methods across U-M natural lands and urban campuses to determine the accurate and efficient protocol for land assessment and ecosystem service valuation that other institutions may scale as relevant.

This paper tested three remote sensing methods to determine land use and land cover (LULC), namely, unsupervised classification, supervised classification and supervised classification incorporating delineated wetlands. Using confusion matrices, this paper tested remote sensing approaches to ground-truthed data, the paper obtained via field-based vegetation surveys across a subset of U-M landholdings.

In natural areas, supervised classification incorporating delineated wetlands was the most accurate and efficient approach. In urban settings, maps incorporating institutional knowledge and campus tree surveys better estimated LULC. Using LULC and literature-based carbon data, this paper estimated that U-M lands store 1.37–3.68 million metric tons of carbon and sequester 45,000–86,000 Mt CO₂e/yr, valued at $2.2m–$4.3m annually ($50/metric ton, social cost of carbon).

This paper compared methods to identify an efficient and accurate remote sensing methodology to identify LULC and estimate carbon storage, biosequestration rates and economic values of ecosystem services provided.

The purpose of this paper is to give a comprehensive survey on the physics-based virtual assembly (PBVA) technology in a novel perspective, to analyze current drawbacks and propose several promising future directions.

To provide a deep insight of PBVA, a discussion of the developing context of PBVA and a comparison against constraint-based virtual assembly (CBVA) is put forward. The core elements and general structure are analyzed based on typical PBVA systems. Some common key issues as well as common drawbacks are discussed, based on which the research trend and several promising future directions are proposed.

Special attention is paid to new research progresses and new ideas concerning recent development as well as new typical systems of the technology. Advantages of PBVA over CBVA are investigated. Based on the analysis of typical PBVA systems and the evolution of PBVA, the core elements of the technology and the general structure of its implementation are identified. Then, current PBVA systems are summarized and classified. After that, key issues in the technology and current drawbacks are explored in detail. Finally, promising future directions are given, including both the further perfecting of the technology and the combination with other technologies.

The PBVA technology is put into a detailed review and analysis in a novel way, providing a better insight of both the theory and the implementation of the technology.