Effects of numerical dissipation on the interpretation of simulation results in computational fluid dynamics

Cadieux, Francois; Sun, Gordon H.; Domaradzki, J. Andrzej

doi:10.1016/j.compfluid.2017.06.009

Cited by 27 publications

(34 citation statements)

References 23 publications

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“…non-hyperbolic, dissipative terms must be introduced to obtain stable numerical solutions. 2 where u is the flow velocity in thex-direction, x is the spatial variable, t is the temporal variable, T is the thermodynamic temperature, µ is the viscosity of the fluid, and k is the thermal conductivity of the fluid. Equations (2.3a) to (2.3c) are the reduced one dimensional Euler equations modified by the addition of viscosity and heat conduction.…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…Equations (2.4a) to (2.4c) is the differential system that is solved with a high order finite difference method. 3 Equations (2.4a) to (2.4c) form 2 Dissipation, regardless as to its origin, physical or artificial, acts to decrease or "smooth out" steep gradients or discontinuities, and thereby acts to generally improve numerical stability. 3 As Galilean transforms relate reference frames that differ only by constant relative motion, spatial derivates remain consistent between the frames or are unchanged by the transformation.…”

Section: Non-dimensionalizationmentioning

confidence: 99%

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Analysis into Asymptotic Convergence to Full Nonlinear Solutions and Exploration of the Implication of Numerical Operator Mutation of Differential Systems

Pocher

Morgan

Peery

et al. 2020

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A robust, sufficiently accurate and practical hydrodynamic simulation toolset is required as a key component of the modeling and simulation of air-gap electrostatic discharge events. This work was performed to complement these ongoing efforts. In particular, hydrodynamic simulations must be vetted to ensure they are robust and sufficiently accurate over relevant characteristic scales. Verification models were generated in order to cultivate the technical knowledge and expertise needed to properly create, implement and execute numerical simulations. Furthermore, this effort was utilized extensively to educate students on the mathematical and numerical principles underlying hydrodynamic simulations. This education opportunity, provided in a holistic and rigorous manner, has greatly benefited developing scientists and engineers with the necessary understandings and toolsets required to excel at accomplishing the task at hand, and, more generally, it has enabled them to generate key programmatic deliverables. This report articulates several subtilties; specifically, how perturbations, nonlinear behavior, and dissipative mechanisms influence numerical stability, how to properly structure mathematical and numerical solutions, and how to properly generate error estimation/assignment. A more rigorous discussion of the consequences of such topics can be found in the body of this report in Chapters 2 and 3 with qualitative findings discussed in Chapter 4. CHAPTER 1

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Section: Mathematical Formulationmentioning

confidence: 99%

Section: Non-dimensionalizationmentioning

confidence: 99%

Analysis into Asymptotic Convergence to Full Nonlinear Solutions and Exploration of the Implication of Numerical Operator Mutation of Differential Systems

Pocher

Morgan

Peery

et al. 2020

View full text Add to dashboard Cite

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“…Continuity equation in the FlowVision takes the same form as in the Fluent software. However, momentum (4) and energy (5) equations are treated in a slightly different way [8].…”

Section: Flow Visionmentioning

confidence: 99%

“…Modelling the impulse flow, damping is not only the effect of calculated physical phenomena but is also a numerical dissipation result. Authors in [5] describes the interpretation problems resulting from numerical dissipation. This paper presents impulse flow damping comparison for different shapes using two solvers with the same flow parameters, boundary conditions and additional models (turbulence, wall functions etc.…”

Section: Introductionmentioning

confidence: 99%

The influence of the numerical solver selection on the nozzle impulse flow simulation results

Młynarczyk

2018

MATEC Web Conf.

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Numerical simulations are currently used for different applications in a various fields of science. Certain solutions are not as obvious as the others while the results can give very valuable conclusions. Computational Fluid Dynamics (CFD) is one of the tools that can be used to solve different problems related with the mass and heat transfer. Nowadays it is already known that the impulse flow simulation allows to determine pressure pulsation attenuation parameters by a given geometry. However, the nozzle shape optimization method strongly depends on the numerical results obtained from the impulse flow simulation. In commercial CFD software Ansys-Fluent the obtained results depends strongly on the chosen numerical methods, especially the spatial discretization method. This is the reason to use other software as a benchmark. Alternative software FlowVision was used to perform the impulse flow simulation for the same geometries to compare the results. As there is a different problem definition in both systems the calculations, accuracy and results differ from each other. The paper describes the numerical differences between solvers. Article contains discussion about obtained results and includes hints how to avoid mistakes when user change software, especially in solving unusual CFD problems.

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“…We address numerical and modelling aspects since both are important, as discussed above, for relaxing the resolution requirements of wall-resolved LES. Cadieux et al [25], for instance, have shown how substantial numerical dissipation in a low-order solver can contaminate the results. In cases of significantly under-resolved LES, Cadieux et al claimed that the results can be re-interpreted as implicit LES.…”

Section: Introductionmentioning

confidence: 99%

Improving LES with OpenFOAM by minimising numerical dissipation and use of explicit algebraic SGS stress model

Montecchia

Brethouwer

Wallin

et al. 2019

Journal of Turbulence

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There is a rapidly growing interest in using general-purpose CFD codes based on second-order finite volume methods for Large-Eddy Simulation (LES) in a wide range of applications, and in many cases involving wall-bounded flows. However, such codes are strongly affected by numerical dissipation and the accuracy obtained for typical LES resolutions is often poor. In the present study, we approach the problem of improving the LES capability of such codes by reduction of the numerical dissipation and use of an anisotropycapturing subgrid-scale (SGS) stress model. The latter is of special importance for wall-resolved LES with resolutions where the SGS anisotropy can be substantial. Here we use the Explicit Algebraic (EA) SGS model [Marstorp L, Brethouwer G, Grundestam O, et al. Explicit algebraic subgrid stress models with application to rotating channel flow. J Fluid Mech. 2009;639:403-432], and comparisons are made for channel flow at friction Reynolds numbers up to 934 with the dynamic Smagorinsky model. The numerical dissipation is reduced by using an OpenFOAM based custom-built flow solver that modifies the Rhie and Chow interpolation and allows to control and minimise its effects without causing numerical instability (in viscous, fully turbulent flows). Different resolutions were used and large improvements of the LES accuracy were demonstrated for skin friction, mean velocity and other flow statistics by use of the new solver in combination with the EA SGS model. By reducing the numerical dissipation and using the EA SGS model the resolution requirements for wall-resolved LES can be significantly reduced.

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Effects of numerical dissipation on the interpretation of simulation results in computational fluid dynamics

Cited by 27 publications

References 23 publications

Analysis into Asymptotic Convergence to Full Nonlinear Solutions and Exploration of the Implication of Numerical Operator Mutation of Differential Systems

Analysis into Asymptotic Convergence to Full Nonlinear Solutions and Exploration of the Implication of Numerical Operator Mutation of Differential Systems

The influence of the numerical solver selection on the nozzle impulse flow simulation results

Improving LES with OpenFOAM by minimising numerical dissipation and use of explicit algebraic SGS stress model

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