scholarly journals Curved interface reconstruction for 2D compressible multi-material flows

2020 ◽  
Vol 67 ◽  
pp. 178-190
Author(s):  
Igor Chollet ◽  
Giulia Lissoni ◽  
Théo Corot ◽  
Philippe Hoch ◽  
Thomas Leroy ◽  
...  
Keyword(s):  
Dynamic Programming ◽  
Unstructured Grid ◽  
Reconstruction Method ◽  
Material Flows ◽  
Two Dimension ◽  
Interface Reconstruction ◽  
Partial Volumes ◽  
Curved Interface

In this paper, we describe an interface reconstruction method in two dimension. This method is an extension of DPIR [1], which reconstructs continuous interfaces and preserves partial volumes using dynamic programming. First we extend the method to curved interfaces. Then, we present tools to improve its robustness in order to apply it to unstructured grid. Finally, we describe an extension to three materials.

A content-adaptive unstructured grid based regularized CT reconstruction method with a SART-type preconditioned fixed-point proximity algorithm

2022 ◽  
Author(s):  
Yun Chen ◽  
Yao Lu ◽  
Xiangyuan Ma ◽  
Yuesheng Xu
Keyword(s):  
Integral Equation ◽  
Fixed Point ◽  
Optimization Problem ◽  
Unstructured Grid ◽  
Reconstruction Technique ◽  
Reconstruction Method ◽  
Ct Reconstruction ◽  
Image Domain ◽  
Computational Costs ◽  
Content Adaptive

Abstract The goal of this study is to develop a new computed tomography (CT) image reconstruction method, aiming at improving the quality of the reconstructed images of existing methods while reducing computational costs. Existing CT reconstruction is modeled by pixel-based piecewise constant approximations of the integral equation that describes the CT projection data acquisition process. Using these approximations imposes a bottleneck model error and results in a discrete system of a large size. We propose to develop a content-adaptive unstructured grid (CAUG) based regularized CT reconstruction method to address these issues. Specifically, we design a CAUG of the image domain to sparsely represent the underlying image, and introduce a CAUG-based piecewise linear approximation of the integral equation by employing a collocation method. We further apply a regularization defined on the CAUG for the resulting illposed linear system, which may lead to a sparse linear representation for the underlying solution. The regularized CT reconstruction is formulated as a convex optimization problem, whose objective function consists of a weighted least square norm based fidelity term, a regularization term and a constraint term. Here, the corresponding weighted matrix is derived from the simultaneous algebraic reconstruction technique (SART). We then develop a SART-type preconditioned fixed-point proximity algorithm to solve the optimization problem. Convergence analysis is provided for the resulting iterative algorithm. Numerical experiments demonstrate the outperformance of the proposed method over several existing methods in terms of both suppressing noise and reducing computational costs. These methods include the SART without regularization and with quadratic regularization on the CAUG, the traditional total variation (TV) regularized reconstruction method and the TV superiorized conjugate gradient method on the pixel grid.

Two-Dimension Temperature Field Reconstruction in Furnace by Acoustic Method

2012 ◽  
Vol 249-250 ◽  
pp. 170-174 ◽  
Author(s):  
Li Na Jia ◽  
Yan Gao ◽  
De Cai Lu
Keyword(s):  
Temperature Field ◽  
Temperature Measurement ◽  
Measurement Data ◽  
Acoustic Method ◽  
Measurement Technology ◽  
Reconstruction Method ◽  
Two Dimension ◽  
Accuracy Of Measurement ◽  
Temperature Measurement System ◽  
Temperature Field Reconstruction

Acoustic temperature measurement technology is a new temperature measuring technology which is rising in recent years. This paper discusses a kind of reconstruction method of temperature field based on acoustic pyrometer. First , acoustic sensors has been used to obtain measurement data, and the technique of wavelet has been used to denoise in order to improve the accuracy of measurement , secondly, the least-squares algorithm has been used to reconstruct temperature field. Finally, we work out our own acoustic temperature measurement system and has got the satisfying result using our own acoustic pyrometer to detect two-dimension temperature field in the laboratory.

Towards 3D Volume-of-Fluid Methods Featuring Subgrid-Scale Capturing of Interface Curvature

2014 ◽  
Author(s):  
Petar Liovic
Keyword(s):  
Volume Of Fluid ◽  
Planar Interface ◽  
Interface Tracking ◽  
Reconstruction Method ◽  
Interfacial Flow ◽  
Subgrid Scale ◽  
Order Accuracy ◽  
Interface Reconstruction ◽  
Interface Curvature ◽  
3D Volume

A new interface reconstruction method for Volume of Fluid (VOF) interface tracking is presented here, based on subgrid-scale planar interface segment reconstruction (SGS-PISR). In the SGS-PISR method implemented here, the centroid of the initial single-surface interface reconstruction is shifted along that normal to enclose the correct volume. An additional step then moves the SGS plane segments laterally outwards, to ameliorate the SGS curvature by blunting the protrusion of the centroid. The SGS-PISR method results in promising tendency towards second-order accuracy and more importantly reduced interface reconstruction errors across a range of mesh resolutions, and is targeted at improving VOF performance in resolving small grid-scale details of the interface topologies in interfacial flow CFD computations.

scholarly journals A smoothed two- and three-dimensional interface reconstruction method

2008 ◽  
Vol 12 (7) ◽  
pp. 365-381 ◽  
Author(s):  
Stewart Mosso ◽  
Christopher Garasi ◽  
Richard Drake
Keyword(s):  
Three Dimensional ◽  
Reconstruction Method ◽  
Interface Reconstruction
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