Large Eddy simulation for engineering applications

Kobayashi, Toshio

doi:10.1016/j.fluiddyn.2005.06.004

Cited by 12 publications

(6 citation statements)

References 35 publications

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“…highest. It is obvious that the spatial filtering function of the incompressible flow equations to define the large eddy and the subgrid modelling problem mainly affect the predict errors [14,15]. Reference to the LES simulation construction for propeller crashback in Vysohlid Ph.D dissertation (2007), the dynamic Smagorinsky model with modification by Lilly (1992) (DSM-Lilly) is used as the SGS in this paper, and it reads…”

Section: Les and Bem Acoustics Methodologymentioning

confidence: 99%

Calculation of propeller’s load noise using LES and BEM numerical acoustics coupling methods

Yang¹,

Wang²,

Zhang³

2011

Boundary Elements and Other Mesh Reduction Methods XXXIII

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Coupling large eddy simulation (LES) and boundary element numerical acoustics methods in the frequency domain to predict the underwater noncavitation far-field load noise in the ship wake flow, which presents a new method to measure the propeller noise level in the ship engineering. The Dynamic Smagorinsky-Lilly model (DSM) is applied to subgrid-scale (SGS) stress tensor in the process of unsteady field LES simulation. Then the sound pressure field is determined solely by the pressure distribution and normal velocity distribution on the closed surface including blades and hub surface after node numbers conservative transfer of the acoustic nodal sources to the acoustic grid. The predicted results show that the steady thrust and torque coefficients of the propeller differ by less than 2% on design point to the experiment data, and the pressure coefficients fit very well. The unsteady calculation can present precisely the blade passing frequency (BPF), its harmonics and wake axis passing frequency (APF) information. Under low frequency, the concentrated area contributing mainly to the noise lies in the blade tip and trailing edge near the root section, whereas for high frequency the source intensity transfers to the blade surface with a centralized pressure load. The spherical surface sound pressure distribution and wake point frequency spectra line of the propeller just get quantitative agreement with the reference calculated results because of the slight difference of ship wake distribution, and the calculated total sound pressure level below 200Hz is 126.4dB.

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Section: Les and Bem Acoustics Methodologymentioning

confidence: 99%

Calculation of propeller’s load noise using LES and BEM numerical acoustics coupling methods

Yang¹,

Wang²,

Zhang³

2011

Boundary Elements and Other Mesh Reduction Methods XXXIII

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“…20 Atualmente, as técnicas de CFD constituem ferramentas capazes de prover soluções adequadas para problemas de avaliação de risco, substituindo modelos resultantes de situações particulares, como os que envolvem dispersão de gás em geometrias regulares. O aumento da velocidade das CPU tem proporcionado a solução de problemas de escoamento em ambientes com geometrias complexas, fornecendo previsões confiáveis a respeito das influências físicas e químicas nos problemas de dispersão de gases sobre obstáculos.…”

Section: Os Modelos De Fluidodinâmica Computacional (Cfd)unclassified

Multiphase Computational Fluid Dynamics Simulation as a Tool for Planning Emergencies with Chemical Agents

Barbosa¹,

Pinto²,

Nogueira³

2014

Revista Virtual De Química

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Numerical simulations provided by fluid dynamic studies have been widely used as effective tools to determine the physical behavior of flows in different situations and geometries. The dispersion of hazardous chemicals gases constitutes one of these branches. In this work, computational fluid dynamics (CFD), combined with dose-response probit functions, is used as a tool for evaluation of environmental risk analysis. The main objective pursued is the integration among the various fields that are responsible for preparing the preliminary design environment and the protective or corrective measures. Given the importance of the proposed approach, coupled with the realization of major world events in Brazil such as 2014 World Cup and 2016 Olympics, the fact that the country is not immune to the actions of terrorist groups, the present study shows the importance of the integration proposed for minimization of harmful effects in case of occurrence of undesirable events.Keywords: OPCW; CFD; Multiphase; emergency response; Chemical Weapons. ResumoAs simulações numéricas relacionadas ao estudo da dinâmica dos fluidos são amplamente utilizadas como uma maneira eficaz para determinar o comportamento físico dos escoamentos nas mais diversas situações e geometrias consideradas. A dispersão de gases de produtos químicos perigosos no ambiente é um dos ramos desses estudos. Dentro deste contexto emprega-se neste trabalho, a fluidodinâmica computacional (CFD), aliada às funções de dose-resposta tipo probit, como ferramenta para análise de risco ambiental, com o objetivo de auxiliar a integração entre os diversos ramos responsáveis pela elaboração prévia do projeto do ambiente e das medidas protetivas ou corretivas em casos de estudos de situações de emergência. Considerando a importância da abordagem proposta e a inserção do Brasil nos quadros de realização de grandes eventos mundiais, como a Copa do Mundo de 2014 e a Olimpíada de 2016, em que o País não estará imune à ações eventuais de grupos terroristas, mostra-se a importância da integração proposta para minimização dos efeitos danosos sobre as pessoas no caso da ocorrência de eventos indesejados.Palavras-chave: CFD multifásico; resposta a emergências; armas químicas.

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“…Then, the generated instantaneous flow data at the outflow boundary of the auxiliary domain were used as the turbulent inflow boundary of the calculation domain for areaway model. In the LES calculations, the code FrontFlow/Red based on the unstructured finite volume method was used, which was developed at the University of Tokyo under the national project "Revolutionary Simulation Software (RSS)" (Kobayashi 2006). The Smagorinsky model with the Smagorinsky constant, C s = 1.2, was used for subgrid-scale modeling.…”

Section: Calculation Descriptionmentioning

confidence: 99%

Measurements and numerical modeling of flow field and pollutant dispersion in areaway space

Kato

Takahashi

2010

Build. Simul.

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In residential building design, areaway can act as an open subsurface space to help improve the living environment in adjacent basement by natural ventilation. To study this particular ventilation phenomenon mainly driven by wind force, the first part of this paper presents an investigation of flow field and pollution dispersion inside areaway space based on a wind tunnel experiment. In the experiment, the measurement of mean velocity, turbulence and concentration as well as the flow visualization were carried out for a rectangular cavity-like areaway model with the width to height (w/h) ratio ranging from 0.3 to 1.0 and the influence of above-ground building has also been investigated. The experimental results reveal quite different airflow patterns characterized with unsteady vortex movement inside the areaway model, which indicates that the w/h ratio and the above-ground building are important factors for ventilating the areaway space. Furthermore, for the purpose of computational fluid dynamics (CFD) model validation, the experimental results of flow fields were compared with the simulation results. The areaway model of w/h = 1 was used for this study and the simulations were performed using large-eddy simulation (LES) and standard k-ε turbulence model. The numerical results show a good agreement with the experimental results when using LES with inflow turbulence. The further investigations with regard to the characteristics of flow field and pollutant removal as well as ventilation performance were also performed by LES.

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Large Eddy simulation for engineering applications

Cited by 12 publications

References 35 publications

Calculation of propeller’s load noise using LES and BEM numerical acoustics coupling methods

Calculation of propeller’s load noise using LES and BEM numerical acoustics coupling methods

Multiphase Computational Fluid Dynamics Simulation as a Tool for Planning Emergencies with Chemical Agents

Measurements and numerical modeling of flow field and pollutant dispersion in areaway space

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