Preconditioning the Quad Dominant Mesh Generator for Ship Structural Analysis

Grubišić, Luka; Lacmanović, Domagoj; Tambača, Josip

doi:10.3390/a15010002

“…The set of surfaces consists of two types of entities: web surfaces (parallelograms with one dimension much smaller than the other) and regular surfaces (convex quadrilaterals defined by four co-planar nodes) [8,22]. Dictionaries which also include warped surfaces have been considered in a followup paper, see [23] for further details. Let us note the following geometrical observation from ([9], Section 4.3).…”

Section: Methodsmentioning

confidence: 99%

An Open-Source Processing Pipeline for Quad-Dominant Mesh Generation for Class-Compliant Ship Structural Analysis

Grubišić

¹

,

Lacmanović

²

,

Palaversa

³

et al. 2022

JMSE

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We present an algorithm for the fully automatic generation of a class-compliant mesh for ship structural analysis. Our algorithm is implemented as an end-to-end solution. It starts from a description of a geometry and produces a class conforming surface mesh as a result. The algorithm consists of two parts, the automatic geometry refinement and the preconditioned Delaunay frontal quad dominant mesh generator. A geometry is described by a dictionary of elements and it contains points, rods, plates, and openings. A dictionary can contain modeling errors such as unintended overlaps or an unintended loss of connectivity between elements. The main contribution of the paper is the automatic geometry refinement algorithm and the virtual stiffener procedure designed to control the local mesh orientation of a marching front meshing algorithm. The geometry refinement algorithm guarantees that the output dictionary will be such that intersections of the boundary edges of plates are guaranteed to be nodes of any mesh generated by tessellating such geometry. The algorithm is implemented in Python, using the open-source Gmsh system together with the Open CASCADE kernel which is used to implement the automatic geometry refinement. We present several benchmark models from an engineering practice to illustrate our claims as well as to benchmark the efficiency of the various stages of the processing pipeline.

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“…The computational mesh is composed of 254 cells that consist of the solid part, contributing to, in total, 10,354 initial cells that compose the whole computational mesh, generated using GMSH open source mesh generator [25], that was also applied in structural ship analysis in Grubišić et al [26]. The mesh sensitivity check, however, has not been carried out, since the Eulerian two-fluid model is used within the study.…”

Section: Generating a Finite Volume Meshmentioning

confidence: 99%

Water Entry of a Heated Axisymmetric Vertical Cylinder

Cukrov,

Landek,

Sato

et al. 2023

Energies

1

0

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The computational model that is able to estimate the temperature distribution inside a solid specimen during the film boiling phase of immersion quenching (water entry) process has been presented in this paper. It is based on the prescribed initial temperatures of the solid specimen and the liquid quenchant. In addition, the turbulence effects have to be considered using the assumed turbulence kinetic energy value, i.e., the “frozen turbulence” approach, that remains constant thorough the simulation. The studied material is nickel alloy, Inconel 600, for which extensive experimental data are available. The work has been carried out using ANSYS Fluent computational fluid dynamics software and the methods for solution of Stefan problem by Eulerian two fluid VOF model. A satisfactory agreement between the experimental and the calculated data has been achieved, yielding thereby the computationally obtained data that fit to a great extent the prescribed error band of ±10% during the estimated film boiling phase of the immersion quenching process itself. It was, however, found that the temperature calculated in the center of a specimen fits this error band until reaching somewhere t < 6 s due to low presumed turbulence level in the domain. In addition, the explosion of the vapor phase after the body reaches the free surface of the quenchant has also been successfully tracked using the numerical simulation model proposed herein. The major novelty of the present research lies in the fact that a moving boundary problem has been successfully resolved in conjunction with, to a great extent, basic-principle-based heat and mass transfer in a turbulent flow conjugate heat transfer (CHT) numerical simulation using moderate computational resources.

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“…The hybrid mesh composed of both the triangular and quadrilateral cells is used in the present numerical simulation, as depicted in Figure 3. The computational mesh is composed of 254 cells that consist of the solid part, contributing to, in total, 10354 initial cells that compose the whole computational mesh, generated using GMSH open source mesh generator [23], that was also applied in structural ship analysis in Grubišić et al [24]. This mesh size is not constant during the computation; yet it is increased due to remeshing procedure.…”

Section: Generating a Finite Volume Meshmentioning

confidence: 99%

Water <span aria-describedby="tippy-18">Entry: A Classical Naval Hydrodynamics Problem Enhanced with the Heat and Mass Transfer, and Applied in an Immersion Quenching Simulation

Cukrov,

Landek,

Sato

et al. 2023

Preprint

0

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The computational model that is able to estimate the temperature distribution inside a solid specimen during the film boiling phase of immersion quenching (water entry) process has been presented in paper, and it is based on the prescribed initial temperatures of the solid specimen and the liquid quenchant. In addition, the turbulence effects have to be considered using the assumed turbulence kinetic energy value, i.e., the “frozen turbulence” approach, that remains constant thorough the simulation. The studied material is nickel alloy, Inconel 600, for which the extensive experimental data is available. The work has been carried out using ANSYS Fluent computational fluid dynamics software and the methods for solution of Stefan problem by Eulerian two fluid VOF model.. A satisfactory agreement between the experimental and the calculated data has been achieved, yielding thereby the computationally obtained data that fits to a great extent to the prescribed error band of ± 10 % during the estimated film boiling phase of the immersion quenching process itself.

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Preconditioning the Quad Dominant Mesh Generator for Ship Structural Analysis

Cited by 3 publications

References 12 publications

An Open-Source Processing Pipeline for Quad-Dominant Mesh Generation for Class-Compliant Ship Structural Analysis

An Open-Source Processing Pipeline for Quad-Dominant Mesh Generation for Class-Compliant Ship Structural Analysis

Water Entry of a Heated Axisymmetric Vertical Cylinder

Water <span aria-describedby="tippy-18">Entry: A Classical Naval Hydrodynamics Problem Enhanced with the Heat and Mass Transfer, and Applied in an Immersion Quenching Simulation

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