Analytical interface reconstruction algorithms in the PLIC‐VOF method for 3D polyhedral unstructured meshes

Dai, Dezhi; Tong, Albert Y.

doi:10.1002/fld.4750

Cited by 21 publications

(13 citation statements)

References 22 publications

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“…Piecewise linear interface calculation (PLIC) schemes have been extensively employed in the volume-of-fluid (VOF) method for interface capturing in numerical simulations of multiphase flows. The PLIC scheme can keep the interface sharp while maintaining mass conservation at the expense of an extra reconstruction step [21]. In each mixed cell with the fraction value ranges from zero to unity, the interface in the PLIC method is approximated by:…”

Section: Interface Reconstruction Modelmentioning

confidence: 99%

“…In the PLIC-VOF method, the solution of the VOF equation can be decomposed into three steps: interface orientation, reconstruction, and advection [21]. In the orientation step, the vector �⃑ is evaluated by using the volume fraction gradient ∇ , i.e., �⃑ = − ∇α ‖∇ ‖ (16) where the negative sign indicates that the orientation vector �⃑ point from liquid to gas.…”

Section: Interface Reconstruction Modelmentioning

confidence: 99%

“…In the orientation step, the vector �⃑ is evaluated by using the volume fraction gradient ∇ , i.e., �⃑ = − ∇α ‖∇ ‖ (16) where the negative sign indicates that the orientation vector �⃑ point from liquid to gas. Then, the interface signed distance is calculated by employing an analytical scheme developed in [21].…”

Section: Interface Reconstruction Modelmentioning

confidence: 99%

See 2 more Smart Citations

Development and Validation of a Two-Phase Thermal-Hydraulic CFD Code NEK-2P

Vegendla

Tentner

Dai

2020

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A project is underway to develop, verify and validate an advanced two-phase flow modeling capability for the highly-scalable, high-performance Computational Fluid Dynamics (CFD) code NEK5000 [1]. The goal of this work is to verify and validate the two-phase version of the NEK5000 code, named NEK-2P, to simulate the two-phase flow and heat transfer phenomena that occur in a Boiling Water Reactor (BWR) fuel bundle under various operating conditions. The NEK-2P two-phase flow models follow the approach used for the Extended Boiling Framework (EBF) [2-3] previously developed at Argonne but include more fundamental physical models of boiling phenomena and advanced numerical algorithms for improved computational accuracy, robustness, and computational speed. The development of the NEK-2P two-phase solver and the implementation of the Extended Boiling Framework two-phase models were initially supported by Argonne National Laboratory (Argonne) through a Laboratory Directed Research and Development (LDRD) project during FY2014-2016. The development and validation of the two-phase models through analyses of selected two-phase boiling flow experiments was supported by the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program in FY2017-2020. This report focuses on verification and validation of the water-steam boiling model NEK-2P Two-Phase, CFD code. The NEK-2P was validated with Nuclear Power Engineering Corporation (NUPEC) Pressurized Water Reactor (PWR) Sub-channel and Bundle Test (PSBT) void distribution benchmark. Three different simulations were performed and analyzed for various operating conditions such as wall-heat flux and sub-cooled inlet temperatures. Reasonably good agreement with measured data was obtained in predicting the measured void distributions. Simulations were performed for Virginia Tech. (VT) 3x3 rod bundle geometry with and without spacers. The preliminary results were presented for Simplified Spacer Grid (SSG). In addition, the implementation of interface reconstruction model was tested with one of the Becker benchmark Critical Heat Flux (CHF) experiments.

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Section: Interface Reconstruction Modelmentioning

confidence: 99%

Section: Interface Reconstruction Modelmentioning

confidence: 99%

Section: Interface Reconstruction Modelmentioning

confidence: 99%

See 1 more Smart Citation

Development and Validation of a Two-Phase Thermal-Hydraulic CFD Code NEK-2P

Vegendla

Tentner

Dai

2020

Self Cite

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“…To date, many studies have used PLIC for interface reconstruction on structured and unstructured grids, and also for related calculations such as calculating the distance between two interfaces, and have proposed improvements to reduce the implementation complexity and increase its efficiency (López et al 2005;Ataei et al 2021b;Dai and Tong 2019;Ataei et al 2021a;Nahed and Dgheim 2020;Scheufler and Roenby 2019). A simple analytical solution can be used to solve PLIC in 2D for a square cell.…”

Section: Introductionmentioning

confidence: 99%

NPLIC: A machine learning approach to piecewise linear interface construction

et al. 2021

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Piecewise Linear Interface Construction (PLIC) is frequently used to geometrically reconstruct fluid interfaces in Computational Fluid Dynamics (CFD) modeling of two-phase flows. PLIC reconstructs interfaces from a scalar field that represents the volume fraction of each phase in each computational cell. Given the volume fraction and interface normal, the location of a linear interface is uniquely defined. For a cubic computational cell (3D), the position of the planar interface is determined by intersecting the cube with a plane, such that the volume of the resulting truncated polyhedron cell is equal to the volume fraction. Yet it is geometrically complex to find the exact position of the plane, and it involves calculations that can be a computational bottleneck of many CFD models. However, while the forward problem of 3D PLIC is challenging, the inverse problem, of finding the volume of the truncated polyhedron cell given a defined plane, is simple. In this work, we propose a deep learning model for the solution to the forward problem of PLIC by only making use of its inverse problem. The proposed model is up to several orders of magnitude faster than traditional schemes, which significantly reduces the computational bottleneck of PLIC in CFD simulations.

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“…In comparison to the bisection/secant method of Ahn and Shashkov [1], Chen and Zhang [4] report a reduction of iterations by 60 to 66%. Dai and Tong [6], following an idea of Diot and François [8], apply a cell rotation to align the PLIC normal with e 3 along with a decomposition of the convex cell into N − 1 prismatoids, where N is the number of unique signed distances of the rotated vertices.…”

Section: Introductionmentioning

confidence: 99%

Face-based Volume-of-Fluid interface positioning in arbitrary polyhedra

Kromer,

Bothe

2021

Preprint

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We introduce a fast and robust algorithm for finding a plane Γ with given normal nΓ, which truncates an arbitrary polyhedron P such that the remaining sub-polyhedron admits a given volume α * |P|. In the literature, this is commonly referred to as Volume-of-Fluid (VoF) interface positioning problem. The novelty of our work is twofold: firstly, by recursive application of the Gaussian divergence theorem, the volume of a truncated polyhedron can be computed at high efficiency, based on summation over quantities associated to the faces of the polyhedron.One obtains a very convenient piecewise parametrization (within so-called brackets) in terms of the signed distance s to the plane Γ. As an implication, one can restrain from the costly necessity to establish topological connectivity, rendering the present approach most suitable for the application to unstructured computational meshes. Secondly, in the vicinity of the truncation position s, the volume can be expressed exactly, i.e. in terms of a cubic polynomial of the normal distance to the PLIC plane. The local knowledge of derivatives enables to construct a root-finding algorithm that pairs bracketing and higher-order approximation. The performance is assessed by conducting an extensive set of numerical experiments, considering convex and non-convex polyhedra of genus (i.e., number of holes) zero and one in combination with carefully selected volume fractions α * (including α * ≈ 0 and α * ≈ 1) and normal orientations nΓ. For all configurations we obtain a significant reduction of the number of (computationally costly) truncations required for the positioning: on average, our algorithm requires between one and two polyhedron truncations to find the position of the plane Γ, outperforming existing methods.

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Analytical interface reconstruction algorithms in the PLIC‐VOF method for 3D polyhedral unstructured meshes

Cited by 21 publications

References 22 publications

Development and Validation of a Two-Phase Thermal-Hydraulic CFD Code NEK-2P

Development and Validation of a Two-Phase Thermal-Hydraulic CFD Code NEK-2P

NPLIC: A machine learning approach to piecewise linear interface construction

Face-based Volume-of-Fluid interface positioning in arbitrary polyhedra

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