Influence of mesh non-orthogonality on numerical simulation of buoyant jet flows

Ishigaki, Masahiro; Abe, Satoshi; Sibamoto, Yasuteru; Yonomoto, Taisuke

doi:10.1016/j.nucengdes.2017.02.010

Cited by 9 publications

(7 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The convergence criterion for the pressure was the residual <10 −8 , and those of the other quantities were the residual <10 −7 . In the previous study, we investigated the influence of the mesh non-orthogonality on the buoyant flows [21]. Then, we applied the non-orthogonal correction to reduce the influence of the mesh non-orthogonality [22].…”

Section: Simulation Methodsmentioning

confidence: 99%

Estimation of Flow Field in Natural Convection with Density Stratification by Local Ensemble Transform Kalman Filter

Ishigaki

Hirose

Abe

et al. 2022

Fluids

Self Cite

View full text Add to dashboard Cite

For estimating thermal flow in a nuclear reactor during an accident accurately, it is important to improve the accuracy of computational fluid dynamics simulations. The temperature and flow velocity are not homogeneous and have large variations in a reactor containment vessel because of its very large volume. In addition, Kelm’s work pointed out that the influence of variations of initial and boundary conditions was important. Therefore, it is necessary to set the initial and boundary conditions taking into account the variations of these physical quantities. However, it is a difficult subject to set such complicated initial and boundary conditions. Then, we can obtain realistic initial and boundary conditions and an accurate flow field by data assimilation, and we can improve the accuracy of the simulation result. In this study, we applied data assimilation by a local ensemble transform Kalman filter to a simulation of natural convection behavior in density stratification, and we performed a twin model experiment. We succeeded in estimating the flow fields and improving the simulation accuracy by the data assimilation, even if we applied the boundary condition with error for the true condition.

show abstract

Section: Simulation Methodsmentioning

confidence: 99%

Estimation of Flow Field in Natural Convection with Density Stratification by Local Ensemble Transform Kalman Filter

Ishigaki

Hirose

Abe

et al. 2022

Fluids

Self Cite

View full text Add to dashboard Cite

show abstract

“…Tetrahedron cells are easy to design, but are known to cause numerical errors and diffusion because of their low quality [25,26]. In contrast, hexahedron cells have advantages in terms of their accuracy and computational efficiency in analysis, although it is difficult to design high-quality cells in the case of complex geometries [7,9]. In addition, with hexahedron cells, a mesh containing a relatively small number of cells can be designed, thereby reducing the computational cost of the numerical analysis.…”

Section: Mesh Qualitymentioning

confidence: 99%

“…Non-orthogonal cells and skewed cells that are generated near complex surfaces are the main sources of numerical errors. In particular, analyses of buoyancy-driven environments, such as those with natural ventilation, are significantly affected by the mesh quality [8,9].…”

Section: Introductionmentioning

confidence: 99%

Building Geometry Simplification for Improving Mesh Quality of Numerical Analysis Model

et al. 2020

View full text Add to dashboard Cite

Numerical analysis, especially the finite volume method (FVM), is one of the primary approaches employed when evaluating a building environment. A complicated geometry can degrade the mesh quality, leading to numerical diffusions and errors. Thus, this study develops and evaluates an automatic building geometry simplification method based on integrating similar surfaces for the geometry of an indoor space. A regression model showed that the complexity of the simplified geometry and its similarity to the original geometry decreased linearly with the threshold of the method. The mesh quality was significantly improved by the simplification. In particular, the maximum skewness decreased exponentially with the threshold of the method. It is expected that the simplification method and regression model presented in this study can be used to quantitatively control the mesh quality.

show abstract

“…In OpenFOAM, the correction method proposed in [111] is available, however, the pressure correction method outlined in the following implicitly includes such a non-orthogonal corrector. For details on this issue, common to most finite volume methods, see [109].…”

Section: Space and Time Discretizationmentioning

confidence: 99%

A partitioned solution approach for fluid-structure interaction problems in the arterial system

Radtke¹

2020

View full text Add to dashboard Cite

The present work is concerned with the partitioned solution of the multifeld problem arising from a hierarchical modeling approach to cardiovascular ﬂuid-structure interaction. Different strategies to couple the participating feld solvers are investigated in detail. This includes staggered and parallel coupling algorithms as well as different methods for convergence acceleration, spatial interpolation and temporal extrapolation of coupling quantities. In the developed modeling and simulation approach, a fully resolved model of a segment of the arterial network is coupled to reduced order models in order to account for the inﬂuence of the surrounding. There is experimental evidence that hemodynamic quantities such as the wall shear stress promote the progression cardiovascular disease. Cardiovascular FSI simulations, that can predict these quantities, are therefore of great interest and can aid in surgical planning and optimization of anastomoses shapes and graft materials. Contents...

show abstract

Influence of mesh non-orthogonality on numerical simulation of buoyant jet flows

Cited by 9 publications

References 14 publications

Estimation of Flow Field in Natural Convection with Density Stratification by Local Ensemble Transform Kalman Filter

Estimation of Flow Field in Natural Convection with Density Stratification by Local Ensemble Transform Kalman Filter

Building Geometry Simplification for Improving Mesh Quality of Numerical Analysis Model

A partitioned solution approach for fluid-structure interaction problems in the arterial system

Contact Info

Product

Resources

About