One-Equation Subgrid Scale Model Using Dynamic Procedure for the Energy Production

Kajishima, Takeo; Nomachi, Takayuki

doi:10.1115/fedsm2003-45348

Cited by 7 publications

(12 citation statements)

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“…Apart from the above-mentioned versions of dynamic SGS models, a new dynamic one-equation SGS model (OD model) was recently proposed by Kajishima and Nomachi [27]. In the OD model, the energy gain in SGS portion and the energy loss in GS portion are considered to be not identical locally and instantaneously; they can be approximated by two different eddy viscosity formulations, respectively.…”

Section: And M Ij = (¯ T /¯ ) 2 |S T |S T Ij −(|S|s Ij )mentioning

confidence: 99%

A new dynamic one‐equation subgrid‐scale model for large eddy simulations

Huang

2009

Numerical Meth Engineering

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(2) no test-filtering operation is needed in determination of dynamic parameters, suitable for low-order numerical discretization and unstructured or hybrid grid situations; and (3) treating the production of SGS kinetic energy and energy loss in grid-scale (GS) portion due to SGS motion with different dynamic mechanisms, which is considered to be more reasonable than the local and instantaneous dynamic mechanism as adopted by most existing one-equation dynamic SGS models. Computational examinations have been conducted for flows with Reynolds number ranging from 3000-70 000, revealing that there are three promising aspects of the new SGS model: (1) adaptability for a wide range of flow regime; (2) less grid dependence; and (3) potential of wide applications in complex geometries and high Reynolds number turbulent flows.

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Section: And M Ij = (¯ T /¯ ) 2 |S T |S T Ij −(|S|s Ij )mentioning

confidence: 99%

A new dynamic one‐equation subgrid‐scale model for large eddy simulations

Huang

2009

Numerical Meth Engineering

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“…The prime objective of the SGS models is to accurately capture small dissipative scales by representing kinetic energy losses due to the viscous forces by accounting for their effect in a statistical manner. Numerous SGS models were developed and most of them are based on the Boussinesq hypothesis [56][57][58][59]. A brief description of the basic and dynamic SGS models is given in the following section.…”

Section: Large Eddy Simulation (Les) Approachmentioning

confidence: 99%

CFD for the Design and Optimization of Slurry Bubble Column Reactors

Basha¹,

Morsi²

2018

Computational Fluid Dynamics - Basic Instruments and Applications in Science

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Despite the notion that computational fluid dynamics (CFD) models are considered complicated, expensive, time-consuming and difficult to formulate, their implementation offers an advanced prospect to move beyond empirical models, which inherit severe limitations in terms of flexibility, scale-up, and optimization of slurry bubble column reactors (SBCRs). This is because complex hydrodynamics coupled with chemical reactions in such reactors increase the uncertainty in using empirical models, leading to significant startup delays and overruns. Recent work by Basha et al. has shown that properly validated CFD models provide an exceptional opportunity to gain detailed temporal and spatial information about the local hydrodynamics and overall behavior as well as performance of SBCRs. This chapter provides a comprehensive overview of different CFD frameworks which could be used to model SBCRs, namely the multi-Eulerian, direct numerical simulations (DNS) and large Eddy simulation (LES). The steps required in developing CFD models and the optimization of different sub-models, such as interphase interactions, solid-phase representation, bubble population balance, bubble-induced turbulence, mass transfer and reaction kinetics are highlighted. Different convergence criteria for meshing, solution stability and techniques for maximizing the CFD model scale without compromising accuracy are addressed. An example of using CFD multi-Eulerian frameworks to describe the local hydrodynamics in a pilot-scale SBCR (0.3-m ID, 3-m height) operating under the Fisher-Tropsch (F-T) synthesis process are also provided.

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“…where V , , , and are the constant [27,28] and Δ is the length scale of filter and can be determined according to Huang and Li's work [26]. The improved LES approach proposed by Huang and Li [26] has been developed as a Fluent User Defined Function (UDF) library, which has been applied in conducting LES simulations of tall buildings and long-span complex roof structures in the previous studies [10,12].…”

Section: Les Turbulence Modelmentioning

confidence: 99%

Numerical Simulation of Fluctuating Wind Effects on an Offshore Deck Structure

Zhou

Han

et al. 2017

Shock and Vibration

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The offshore structures that play a vital role in oil and gas extraction are always under complicated environmental conditions such as the random wind loads. The structural dynamic response under the harsh wind is still an important issue for the safety and reliable design of offshore structures. This study conducts an investigation to analyze the wind-induced structural response of a typical offshore deck structure. An accurate and efficient mixture simulation method is developed to simulate the fluctuating wind speed, which is then introduced as the boundary condition into numerical wind tunnel tests. Large eddy simulation (LES) is utilized to obtain the time series of wind pressures on the structural surfaces and to determine the worst working condition. Finally, the wind-induced structural responses are calculated by ANSYS Parametric Design Language (APDL). The numerically predicted wind pressures are found to be consistent with the existing experimental data, demonstrating the feasibility of the proposed methods. The wind-induced displacements have the certain periodicity and change steadily. The stresses at the top of the derrick and connections between deck and derrick are relatively larger. These methods as well as the numerical examples are expected to provide references for the wind-resistant design of the offshore structures.

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One-Equation Subgrid Scale Model Using Dynamic Procedure for the Energy Production

Cited by 7 publications

References 0 publications

A new dynamic one‐equation subgrid‐scale model for large eddy simulations

A new dynamic one‐equation subgrid‐scale model for large eddy simulations

CFD for the Design and Optimization of Slurry Bubble Column Reactors

Numerical Simulation of Fluctuating Wind Effects on an Offshore Deck Structure

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