Fast Surface Denoising Using Finite Volumes of the Dual Mesh

2012 ◽  
Author(s):  
Anis Kacem ◽  
A. Ben Hamza
Keyword(s):  
Finite Volumes ◽  
Dual Mesh

scholarly journals A dual mesh method with adaptivity for stress-constrained topology optimization

2019 ◽  
Vol 61 (2) ◽  
pp. 749-762 ◽  
Author(s):  
Daniel A. White ◽  
Youngsoo Choi ◽  
Jun Kudo
Keyword(s):  
Topology Optimization ◽  
Mesh Method ◽  
Dual Mesh

Dual-Primal Mesh Optimization for Polygonized Implicit Surfaces With Sharp Features

2002 ◽  
Vol 2 (4) ◽  
pp. 277-284 ◽  
Author(s):  
Yutaka Ohtake ◽  
Alexander G. Belyaev
Keyword(s):  
Adaptive Mesh ◽  
Implicit Surfaces ◽  
Marching Cubes ◽  
Triangle Mesh ◽  
Implicit Surface ◽  
Weighted Vertex ◽  
Visualization Toolkit ◽  
Object Oriented Approach ◽  
Speed And Accuracy ◽  
Dual Mesh

A new method for improving polygonizations of implicit surfaces with sharp features is proposed. The method is based on the observation that, given an implicit surface with sharp features, a triangle mesh whose triangles are tangent to the implicit surface at certain inner triangle points gives a better approximation of the implicit surface than the standard Marching Cubes mesh [Lorensen, W.E., and Cline, H.E., 1987, Computer Graphics (Proceedings of SIGGRAPH ’87), 21(3), pp. 163–169] (in our experiments we use VTK Marching Cubes [Schroeder, W., Martin, K., and Lorensen, W., 1998, The Visualization Toolkit: An Object-Oriented Approach to 3-D Graphics, Prentice Hall]). First, given an initial triangle mesh, its dual mesh composed of the triangle centroids is considered. Then the dual mesh is modified such that its vertices are placed on the implicit surface and the mesh dual to the modified dual mesh is considered. Finally the vertex positions of that “double dual” mesh are optimized by minimizing a quadratic energy measuring a deviation of the mesh normals from the implicit surface normals computed at the vertices of the modified dual mesh. In order to achieve an accurate approximation of fine surface features, these basic steps are combined with adaptive mesh subdivision and curvature-weighted vertex resampling. The proposed method outperforms approaches based on the mesh evolution paradigm in speed and accuracy.

scholarly journals ON QUANTUM MARKOV CHAINS ON CAYLEY TREE I: UNIQUENESS OF THE ASSOCIATED CHAIN WITH XY-MODEL ON THE CAYLEY TREE OF ORDER TWO

2011 ◽  
Vol 14 (03) ◽  
pp. 443-463 ◽  
Author(s):  
LUIGI ACCARDI ◽  
FARRUKH MUKHAMEDOV ◽  
MANSOOR SABUROV
Keyword(s):  
Markov Chains ◽  
Boundary Conditions ◽  
Cayley Tree ◽  
Weak Limit ◽  
Finite Volumes ◽  
Xy Model ◽  
Quantum Markov Chains

In this paper we study forward quantum Markov chains (QMC) defined on Cayley tree. A construction of such QMC is provided, namely we construct states on finite volumes with boundary conditions, and define QMC as a weak limit of those states which depends on the boundary conditions. Using the provided construction, we investigate QMC associated with XY-model on a Cayley tree of order two. We prove uniqueness of QMC associated with such a model, this means the QMC does not depend on the boundary conditions.

A Dual-Mesh Unstructured Adaptive Cartesian Computational Fluid Dynamics Approach for Hover Prediction

2016 ◽  
Vol 61 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Andrew M. Wissink ◽  
Mark Potsdam ◽  
Venkateswaran Sankaran ◽  
Jayanarayanan Sitaraman ◽  
Dimitri Mavriplis
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Dual Mesh

scholarly journals Un Modelo Numérico 1D en Volúmenes Finitos para la Solución de las Ecuaciones de Flujo e Infiltración del Riego por Gravedad en Melgas

2019 ◽  
pp. 22-30
Keyword(s):  
Numerical Scheme ◽  
Finite Volumes ◽  
Computational Tool ◽  
Important Paper ◽  
Water Load ◽  
El Sistema ◽  
Longitudinal Slope ◽  
Richards’S Equation ◽  
Supercritical Flows ◽  
The Mathematical Model

Un Modelo Numérico 1D en Volúmenes Finitos para la Solución de las Ecuaciones de Flujo e Infiltración del Riego por Gravedad en Melgas A Numerical Model 1D in Finite Volumes for the Solution of the Equations of Flow and Infiltration of the Gravity in Border Irrigation Pino Vargas Edwin, Mejía Marcacuzco J. Abel, Chávarri Velarde Eduardo Universidad Nacional Jorge Basadre Grohmann, Tacna, Perú Universidad Nacional Agraria La Molina, Lima, Perú DOI: https://doi.org/10.33017/RevECIPeru2012.0006/ RESUMEN El desarrollo de este modelo permitirá contar con una herramienta computacional para diseñar adecuadamente el sistema de riego por melgas, reduciendo las pérdidas de agua y utilizándola de manera optima para mejorar la productividad de los cultivos, bajo las premisas de uso eficiente de agua, es decir cultivos de mayor productividad, al más bajo consumo de agua, usando metodologías de producción óptimas. Se implemento el esquema numérico en volúmenes finitos para las ecuaciones de flujo Saint Venant, lo cual permitió conocer el perfil de flujo superficial y la infiltración en el suelo según el avance del riego. Luego del proceso de simulación de varios casos se logro establecer que pendiente longitudinal juega un papel importante en el flujo para las melgas según el modelo planteado se tiene que la pendiente debe ser menor 0,001 m/m. Las pendientes mayores generan flujos rápidos o súper críticos lo cual no es recomendable en el diseño de las melgas, puesto que será una fuente directa de erosión. En cuanto a los caudales de ingreso a las melgas la bibliografía señala un rango para melgas de 1 a 5 l/s/m, lo cual ha sido empleado en el modelo sin ningún inconveniente. En este trabajo se reduce la ecuación de Richards a su expresión unidimensional más su componente temporal y los resultados cumplen satisfactoriamente el objetivo de predecir el movimiento del agua en el subsuelo a partir de datos de propiedades físicas de los suelos y condiciones impuestas tipo dirichlet de carga de agua sobre el suelo. En cuanto a la validación del modelo matemático con datos referenciales de trabajos de investigación se uso el trabajo realizado por Saucedo (2005) para el flujo en superficie y Dahualde G. (2005) para el proceso de infiltración. Se puede contrastar los resultados con algunas diferencias atribuibles a la solución de las ecuaciones, al método numérico empleado y el esquema de solución. Descriptores: Flujo Superficial, Volúmenes Finitos, Infiltración, Modelamiento Numérico 1D, Melgas. ABSTRACT The development of this model will allow to possess a computational tool to design adequately the system of border irrigation, reducing the water loss and using in an ideal way to improve the productivity of the cultures, under the premises of efficient use of water, that is to say cultures of major productivity, to the lowest consumption of water, using methodologies of production optimal. Was implemented the numerical scheme in finite volumes for the equations of flow Saint Venant, which allowed knowing the profile of superficial flow and the infiltration in the soil according to the advance of the irrigation. After the process of simulation of several, cases, was managed to establish that the longitudinal slope plays an important paper in the flow for the border irrigation according to the raised model the slope must be minor 0,001 m/m. The major slopes generate rapid or supercritical flows, which is not advisable in the design of the border irrigation, since it will be a direct source of erosion. As for flows of revenue of border irrigation the bibliography indicates a range from 1 to 5 l/s/m, which has been an employee in the model without any disadvantage. In this work Richards's equation is diminishes to his expression unidimensional more his temporary component and the results fulfill satisfactorily the aim to predict the movement of the water in the subsoil, from information of physical properties of the soils 23 and imposed conditions dirichlet type of water load on the soil. As for the validation of the mathematical model with referential data of works of investigation was used the work realized by Osier-bed (2005) for the flow in surface and Dahualde G. (2005) for the process of infiltration. It is possible to confirm the results with some differences attributable to the solution of the equations, to the numerical used method and the scheme of solution. Keywords: Superficial flow, Finite Volumes, Infiltration, Numerical Modeling 1D, Border Irrigation.

scholarly journals Additivity of relative magnetic helicity in finite volumes

2020 ◽  
Vol 643 ◽  
pp. A26
Author(s):  
Gherardo Valori ◽  
Pascal Démoulin ◽  
Etienne Pariat ◽  
Anthony Yeates ◽  
Kostas Moraitis ◽  
...  
Keyword(s):  
Complex Dynamics ◽  
Flux Rope ◽  
Dynamical Evolution ◽  
Finite Volumes ◽  
Magnetic Helicity ◽  
Relaxation Processes ◽  
Gauge Invariant ◽  
Hydrodynamic Evolution ◽  
Solar Eruptions ◽  
Unified View

Context. Relative magnetic helicity is conserved by magneto-hydrodynamic evolution even in the presence of moderate resistivity. For that reason, it is often invoked as the most relevant constraint on the dynamical evolution of plasmas in complex systems, such as solar and stellar dynamos, photospheric flux emergence, solar eruptions, and relaxation processes in laboratory plasmas. However, such studies often indirectly imply that relative magnetic helicity in a given spatial domain can be algebraically split into the helicity contributions of the composing subvolumes, in other words that it is an additive quantity. A limited number of very specific applications have shown that this is not the case. Aims. Progress in understanding the nonadditivity of relative magnetic helicity requires removal of restrictive assumptions in favor of a general formalism that can be used in both theoretical investigations and numerical applications. Methods. We derive the analytical gauge-invariant expression for the partition of relative magnetic helicity between contiguous finite volumes, without any assumptions on either the shape of the volumes and interface, or the employed gauge. Results. We prove the nonadditivity of relative magnetic helicity in finite volumes in the most general, gauge-invariant formalism, and verify this numerically. We adopt more restrictive assumptions to derive known specific approximations, which yields a unified view of the additivity issue. As an example, the case of a flux rope embedded in a potential field shows that the nonadditivity term in the partition equation is, in general, non-negligible. Conclusions. The nonadditivity of relative magnetic helicity can potentially be a serious impediment to the application of relative helicity conservation as a constraint on the complex dynamics of magnetized plasmas. The relative helicity partition formula can be applied to numerical simulations to precisely quantify the effect of nonadditivity on global helicity budgets of complex physical processes.

Spatial Transients in Finite Volumes

2004 ◽  
Vol 33 (3-4) ◽  
pp. 311-329
Author(s):  
Mihály Makai
Keyword(s):  
Finite Volumes
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