On overset interpolation strategies and conservation on unstructured grids in OpenFOAM

Chandar, Dominic

doi:10.1016/j.cpc.2019.01.009

Cited by 26 publications

(25 citation statements)

References 9 publications

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“…(1) The significantly higher computational cost (Jung and Kwon, 2009) (2) The introduction of numerical errors in the volume of fluid environment, such as violation of mass conservation (Chandar, 2019;Ferziger and Peric, 2001) (3) The limited availability of the overset grid method in commonly used CFD software.…”

Section: Related Studiesmentioning

confidence: 99%

“…The updated overset grid method in v1812 is assessed by Windt et al (2019a), finding a significant improvement compared to the initial v1706 implement-ation assessed (Windt et al, 2018a) and, thus, showing potential for the application of WEC experiments, specifically for control studies. In (Windt et al, 2019a), the overset implementation in v1812 is also compared to the in-house overset toolbox, opera (Chandar, 2019). While the two overset implementations are found to display good agreement in terms of WEC motion, opera shows considerably better computational efficiency.…”

Section: Related Studiesmentioning

confidence: 99%

“…For multi-phase problems, the conservation issues can results in artificial water convection, indicated by a change of the water level. For a detailed analysis of interpolation strategies and their implications on the solution accuracy, the interested reader is referred to Chandar (2019). This section presents the case studies, used to assess the performance of the opera overset grid method, and to model a WEC under controlled conditions.…”

Section: Identification Of Hole Cells 2 Identification Of Fringe Cells 3 Identification Of Donor Cells 4 Interpolation Between Fringe Andmentioning

confidence: 99%

“…For a more detailed description of the opera algorithm, and some performance assessment studies, the interested reader is referred to Chandar (2019).…”

Section: Operamentioning

confidence: 99%

“…Among these methods, the overset grid method shows particular potential for handling large amplitude, multi-degree of freedom, WEC motion (Windt et al, 2018a(Windt et al, , 2019a. The overset grid method, implemented in the OpenFOAM CFD toolbox opera, developed at the Institute Of High Performance Computing, Singapore (Chandar, 2019), is used here to assess its feasibility for WEC control studies.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Evaluation of the overset grid method for control studies of wave energy converters in OpenFOAM numerical wave tanks

Windt

Davidson

Chandar

et al. 2019

J. Ocean Eng. Mar. Energy

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Computational fluid dynamics (CFD) based numerical wave tanks are valuable tools for the development and evaluation of energy maximising control systems for wave energy converters (WECs). However, the exaggerated body motion amplitude, which can be induced by the energy maximising control system, challenges the commonly applied mesh morphing method in CFD, due to the resulting mesh distortion and subsequent numerical instability. A more advanced mesh motion method is the overset grid method, which can inherently handle large amplitude body motions and has recently become freely available in the open source CFD software OpenFOAM. The overset grid method can, therefore, potentially eliminate the mesh distortion problem, hindering the simulation of WECs under controlled conditions. To evaluate the capability of the overset grid method for control studies of WECs in an OpenFOAM numerical wave tank, this paper presents a detailed comparison of the overset grid and mesh morphing methods, considering five test cases of increasing complexity. The test cases range from a static equilibrium test to the modelling of a controlled WEC, and good agreement is demonstrated between the two mesh motion methods, except for the case of the controlled WEC, when the device motion becomes

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Section: Related Studiesmentioning

confidence: 99%

Section: Related Studiesmentioning

confidence: 99%

Section: Identification Of Hole Cells 2 Identification Of Fringe Cells 3 Identification Of Donor Cells 4 Interpolation Between Fringe Andmentioning

confidence: 99%

“…For a more detailed description of the opera algorithm, and some performance assessment studies, the interested reader is referred to Chandar (2019).…”

Section: Operamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation of the overset grid method for control studies of wave energy converters in OpenFOAM numerical wave tanks

Windt

Davidson

Chandar

et al. 2019

J. Ocean Eng. Mar. Energy

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On the accuracy, robustness, and performance of high order interpolation schemes for the overset method on unstructured grids

Lemaire

Vaz

Rijswijk

et al. 2021

Numerical Methods in Fluids

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A comprehensive study on interpolation schemes used in overset grid techniques is here presented. Based on a literature review, numerous schemes are implemented, and their robustness, accuracy, and performance are assessed. Two code verification exercises are performed for this purpose: a 2D analytical solution of a laminar Poiseuille steady flow; and an intricate manufactured solution of a turbulent flow case, characteristic of a boundary layer flow combined with an unsteady separation bubble. For both cases, the influence of grid layouts, grid refinement, and time-step is investigated. Local and global errors, convergence orders, and mass imbalance are quantified. In terms of computational performance, strong scalability, cpu timings, load imbalancing, and domain connectivity information (DCI) overhead are reported. The effect of the overset-grid interpolation schemes on the numerical performance of the solver, that is, number of nonlinear iterations, is also scrutinized. The results show that, for a second order finite volume code, once diffusion is dominant (low Reynolds number), interpolation schemes higher than second order, for example, least squares of degree 2, are needed not to increase the total discretization errors. For convection dominated flows (high Reynolds numbers), the results suggest that second order schemes, for example, nearest cell gradient, are sufficient to prevent overset grid schemes to taint the underlying discretization errors. In terms of performance, by single-process and parallel communication optimization, the total overset-grid overhead (with DCI done externally to the CFD code) may be less than 4% of the total run time for second-order schemes and 8% for third-order ones, therefore empowering higher-order schemes and more accurate solutions.

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High-fidelity modelling of lift-based wave energy converters in a numerical wave tank

Olbert

Abdel‐Maksoud

2023

Applied Energy

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On overset interpolation strategies and conservation on unstructured grids in OpenFOAM

Cited by 26 publications

References 9 publications

Evaluation of the overset grid method for control studies of wave energy converters in OpenFOAM numerical wave tanks

Evaluation of the overset grid method for control studies of wave energy converters in OpenFOAM numerical wave tanks

On the accuracy, robustness, and performance of high order interpolation schemes for the overset method on unstructured grids

High-fidelity modelling of lift-based wave energy converters in a numerical wave tank

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