70 results about "Volume mesh" patented technology

A multi-scale finite-volume (MSFV) method to solve elliptic problems with a plurality of spatial scales arising from single or multi-phase flows in porous media is provided. Two sets of locally computed basis functions are employed. A first set of basis functions captures the small-scale heterogeneity of the underlying permeability field, and it is computed to construct the effective coarse-scale transmissibilities. A second set of basis functions is required to construct a conservative fine-scale velocity field. The method efficiently captures the effects of small scales on a coarse grid, is conservative, and treats tensor permeabilities correctly. The underlying idea is to construct transmissibilities that capture the local properties of a differential operator. This leads to a multi-point discretization scheme for a finite-volume solution algorithm. Transmissibilities for the MSFV method are preferably constructed only once as a preprocessing step and can be computed locally. Therefore, this step is well suited for massively parallel computers. Furthermore, a conservative fine-scale velocity field can be constructed from a coarse-scale pressure solution which also satisfies the proper mass balance on the fine scale. A transport problem is ideally solved iteratively in two stages. In the first stage, a fine scale velocity field is obtained from solving a pressure equation. In the second stage, the transport problem is solved on the fine cells using the fine-scale velocity field. A solution may be computed on the coarse cells at an incremental time and properties, such as a mobility coefficient, may be generated for the fine cells at the incremental time. If a predetermined condition is not met for all fine cells inside a dual coarse control volume, then the dual and fine scale basis functions in that dual coarse control volume are reconstructed.

In a method for domain decomposition for generating unstructured grids, a surface mesh is generated for a spatial domain. A location of a partition plane dividing the domain into two sections is determined. Triangular faces on the surface mesh that intersect the partition plane are identified. A partition grid of tetrahedral cells, dividing the domain into two sub-domains, is generated using a marching process in which a front comprises only faces of new cells which intersect the partition plane. The partition grid is generated until no active faces remain on the front. Triangular faces on each side of the partition plane are collected into two separate subsets. Each subset of triangular faces is renumbered locally and a local / global mapping is created for each sub-domain. A volume grid is generated for each sub-domain. The partition grid and volume grids are then merged using the local-global mapping.

Methods for indoor 3D surface reconstruction and 2D floor plan recovery by segmenting a number of objects and building structure elements from a building scan using an electronic computing device are presented, the methods including: causing the electronic computing device to capture the building scan, where the building scan includes a number of scan points; pre-processing scan data from the building scan; generating an octree and a 2.5D model from the pre-processed scan data; extracting interior and exterior volumes from the octree model and the 2.5D model; and meshing the extracted volumes to generate a 3D object geometry and a 3D building geometry, where the 3D object geometry corresponds with the number of objects and the 3D building geometry corresponds with the indoor 3D surface reconstruction of building structure elements.

Four-dimensional (4D) computed tomography (CT) is simulated by first generating a surface mesh from a single thoracic CT scan. Tetrahedralization is applied to the surface mesh to obtain a first volume mesh. Finite element analysis, using boundary constraints and load definitions, is applied to the first volume mesh to obtain a lung deformation according to an Ogden model. Constrained tetrahedralization, using control points, is applied to the lung deformation to obtain a second volume mesh, which is then deformed using mass-spring-damper simulation to produces the 4DCT.

The method enables a non-homogeneous diffusing object to be examined by illuminating the object with a continuous light by means of a light source. It previously comprises reconstruction of the three-dimensional spatial mapping of an attenuation variable representative of the diffusion and absorption non-homogeneities of the object, by resolving a diffusion equation∇2F({right arrow over (r)}S, {right arrow over (r)})−k′2({right arrow over (r)})F({right arrow over (r)}S, {right arrow over (r)})=ASδ({right arrow over (r)}−{right arrow over (r)}S).In the diffusion equation, AS is a constant, {right arrow over (r)} the spatial coordinate of any point of the mesh of a volume at least partially containing the object, and {right arrow over (r)}S the spatial coordinate of the light source. The transfer functions of an equation used for reconstructing the distribution of fluorophores integrate the attenuation variable reconstituted in this way.

The invention is a computer implemented method, device, system, or article for reconstructing a surface of an object. In particular, the invention comprises estimating a non-convex hull signed distance function parameters from a data set of an object and evaluating the non-convex hull signed distance function on vertices of a volumetric mesh. The invention further comprises approximating the zero level set of the non-convex hull signed distance function by a polygonal mesh using an isosurface algorithm to provide surface reconstruction of an object.

A method and machine-readable medium provide a technique to modify a hexahedral finite element volume mesh using dual generation and sheet insertion. After generating a dual of a volume stack (mesh), a predetermined algorithm may be followed to modify (refine) the volume mesh of hexahedral elements. The predetermined algorithm may include the steps of locating a sheet of hexahedral mesh elements, determining a plurality of hexahedral elements within the sheet to refine, shrinking the plurality of elements, and inserting a new sheet of hexahedral elements adjacently to modify the volume mesh. Additionally, another predetermined algorithm using mesh cutting may be followed to modify a volume mesh.

In a method for domain decomposition for generating unstructured grids, a surface mesh is generated for a spatial domain. A location of a partition plane dividing the domain into two sections is determined. Triangular faces on the surface mesh that intersect the partition plane are identified. A partition grid of tetrahedral cells, dividing the domain into two sub-domains, is generated using a marching process in which a front comprises only faces of new cells which intersect the partition plane. The partition grid is generated until no active faces remain on the front. Triangular faces on each side of the partition plane are collected into two separate subsets. Each subset of triangular faces is renumbered locally and a local / global mapping is created for each sub-domain. A volume grid is generated for each sub-domain. The partition grid and volume grids are then merged using the local-global mapping.

Method for generating a 3D grid, and for defining a material property model on the grid, to use, for example, in a reservoir simulator. A mapping is defined (61,71) to a design space in which the material property is described as a piecewise smooth implicit or explicit function in three dimensions. Grid geometry is constructed only in the physical space of the model (62-65,73-76), and no grid is required in the design space. The material property, for example permeability, is sampled in the design space (66,77) to populate the cells in the grid constructed in the physical domain. Prismatic grid cells may be truncated based on faults and horizons (65), or maybe conformed to fault surfaces using a 3D parameterization of the model (76). Only forward mapping, i.e. from the physical domain to the design space, is required.

A method of computer simulation of an aerodynamic behavior of an aircraft in flight close to the ground includes generating a volume mesh of a three-dimensional geometric domain. The volume mesh is at least partly delimited by a three-dimensional geometric model of the aircraft and by a plane modelling the ground. The volume mesh defines a computational domain. The method also includes imposing a uniform boundary condition on the plane comprising a predetermined speed vector with a non-zero tangential component and a non-zero normal component, and solving a discrete numerical model of the Navier-Stokes equations by computer on the volume mesh with the uniform boundary condition imposed on the plane to obtain a numerical solution of a fluid flow inside said computational domain.

The invention provides a bottom water reservoir horizontal well water flooding numerical simulation method based on a quasi-streamline method, which comprises the following steps: step 1, collecting basic static and dynamic information of a reservoir, and providing parameters for numerical simulation calculation; step 2, calculating parameter tables such as Kro, Krw, fw, fw 'and PV under each water saturation according to the relative permeability experiment data; 3, determining quasi-streamline distribution according to the form of the bottom water ridge, and performing isovolumetric mesh generation along the streamline; 4, initializing a model, and setting initial saturation, a pressure boundary and the like of a grid according to the actual condition of an oil reservoir; step 5, calculating simulation parameters such as saturation field distribution, seepage resistance and the like according to a water drive leading edge displacement theory. Aiming at the understanding problem of the water displacement rule of the bottom water reservoir, a bottom water displacement theoretical model is established by adopting a quasi-streamline method, the development dynamics of a horizontal well of the bottom water reservoir are simulated, and theoretical and technical support is provided for making a bottom water reservoir development technical policy.

The invention provides and discloses a simulation method and a simulation device of a passenger compartment refrigeration effect. The method comprises the following steps: reading the three-dimensional graph of a passenger compartment and the three-dimensional graph of a human body in the passenger compartment; executing surface mesh division on the passenger compartment and the surface of the human body; repeatedly repairing the mesh quality of surface meshes; on the basis of the repaired surface mesh, dividing space in the passenger compartment into volume meshes; calling a fluid physical model, and loading the three-dimensional graph of the passenger compartment, the three-dimensional graph of the human body in the passenger compartment, and the volume meshes formed by the division of unfilled space into the fluid physical model; setting a fluid boundary condition, and calculating and outputting fluid performance parameters of volume meshes according to the fluid boundary condition. According to the simulation method, an airflow movement direction in the passenger compartment, the airflow speed of the human body surface, the distribution situation of airflow on the human body surface and the like can be obtained for evaluating whether the refrigeration effect of the passenger compartment conforms to the standard of the comfort level of the passenger compartment. Time is saved, manpower and financial resource consumption can be reduced, and cost is greatly reduced.