An hybrid RANS/LES model for simulation of complex turbulent flow

Wei, Qun; Chen, Hongxun; Ma, Zheng

doi:10.1016/s1001-6058(16)60684-4

Cited by 20 publications

(5 citation statements)

References 13 publications

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“…Where  is the turbulent dissipation rate, μ C denotes the eddy viscosity coefficient. According to the results of experiments (Champagne et al 1970;Tavoularis and Corrsin 1981) and the DNS (Lee et al 1990;Rogers and Moin 1987), the non-linear eddy viscosity model had been proposed by Wei et al (2016) and was applied first to investigate the pressure fluctuation characteristics of the centrifugal pump.…”

Section:  mentioning

confidence: 99%

“…The URANS_SSTNL model diminishes deviation, but the DDES_NL model offers the smallest discrepancy. Figure 3 shows the comparison of the calculated turbulent structures and the experimental (Htun 2004;Wei et al 2016) (The second invariant of velocity gradient tensor is used to describe (Q-criterion(Q = S 2 − Ω 2 , S being the strain rate and Ω the vorticity))), Htun M studied the influence of the size and direction of the top angle and the angle of attack on the structure of the flow through the triangular cylinder in a wind tunnel and conducted an experimental study; colored according to the velocity), it is apparent that all models can capture the periodic vortex shedding, the conventional URANS method only obtains the vortex structure of a single mode, while the DDES_NL method exhibits the ability to automatically detect the separation zone and switch to the LES mode for solving in the separation zone, thus capturing a richer large-scale turbulence structure.…”

Section: Front and Backmentioning

confidence: 99%

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A Delayed Detached Eddy Simulation Model for the Simulation of Complex Turbulent Flow

2022

JAFM

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A new turbulent model based on Delayed Detached Eddy Simulation (DDES) with non-linear eddy viscosity model (NLEVM) was developed to predict the complex turbulent flow. The numerical simulation of the triangular cylinder and the centrifugal pump was carried out to investigate the ability and applicability of the DDES model based on NLEVM (DDES_NL). Compared to the turbulent model based on the eddy viscosity model, the computational results of the triangular cylinder showed the advantage of the non-linear eddy viscosity modification in the DDES_NL model which can improve the accuracy of the prediction in the flow phenomenon with a relatively simple turbulence structure. Regrettably, some small-scale turbulent structures among those still cannot be captured accurately. The numerical simulation of the centrifugal pump predicted by the DDES_NL model shows more abundant flow structures and gets close to the realistic statistical characteristics. It also proves the good applicability of the DDES_NL model in complex flow. This study aims to contribute to the growing area of turbulence modeling by exploring it.

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Section:  mentioning

confidence: 99%

Section: Front and Backmentioning

confidence: 99%

A Delayed Detached Eddy Simulation Model for the Simulation of Complex Turbulent Flow

2022

JAFM

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“…Then the turbulence model was replaced as LES with the Smargorinsky-Lily mode, and the unsteady force and flow field were simulated [27,28,29]. In all the simulations which were run by using the Pressure-Based solver [30,31], the SIMPLEC algorithm was applied for Pressure-Velocity Coupling, with Least Squares Cell Based for gradient discretization, with PRESTO for pressure discretization, and with Bounded Central Differencing for momentum discretization. Sliding mesh technique was applied to the rotation motion simulation.…”

Section: Turbulence Modelmentioning

confidence: 99%

Numerical Prediction on Vibration and Noise Reduction Effects of Propeller Boss Cap Fins on a Propulsion System

Sun

et al. 2020

brod

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To investigate the vibration and noise reduction effects of Propeller Boss Cap Fins (PBCF), the Large Eddy Simulation (LES) method has been employed in the noise performance estimation of a propeller-rudder system. The hydrodynamic performance of the propulsion system is predicted after the grid independence analysis, then further compared with the result of cavitation tunnel experiment. The acoustic simulation is performed based on Ffowcs Williams and Hawkings (FW-H) equation. After the observation of the hydrodynamic noise performance changes, the forces of propulsion systems and noise reduction effects of PBCF are analyzed. It's indicated from the research results that PBCF can not only improve the propulsion efficiency, but also reduce the radiation noise intensity significantly. Meanwhile, the lateral force fluctuation of hub cap can be decreased by suppressing the vibration of propeller shaft. In addition, the time-averaged value of the rudder lateral force has been decreased by about 15.5%. It has been well known that the radiation of propulsion noise is directional. Accordingly, it is found that the noise reduction effects due to PBCF are also directional, which is the most noticeable in the axial direction.

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“…Furthermore, the DES method has great advantages: it can be applied at high Reynolds numbers, and it is suitable to solve geometry-dependent, unsteady three-dimensional turbulent motions, similar to the large eddy simulation (LES) model. The model combines the advantages of the RANS (for the near-wall regions) and LES (used in the free-stream) models; consequently, it has the potential to offer more accuracy than RANS at less cost than LES [33].…”

Section: Analysis Turbulence Model Guide Vanes' State Iterations/timementioning

confidence: 99%

Numerical Study on the Internal Flow Field of a Reversible Turbine during Continuous Guide Vane Closing

et al. 2017

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The unsteady flow field in a reversible pump-turbine is investigated during the continuous load rejection using a 3D computational fluid dynamic analysis. Numerical calculations are carried out using the detached eddy simulation (DES) turbulence model and a new approach involving automatic mesh motion. In this way, the instability of the flow field is analyzed by continuously changing the guide vane openings from the best efficiency point (BEP). Unsteady flow characteristics are described by post-processing signals for several monitoring points including mass flow, torque, head and pressure in the frequency and time-frequency domains. The formation of vortices of different scales is observed from the origin to further enlargement and stabilization; the effect of the rotating structures on the flow passage is analyzed, and the influence of unsteady flow development on the performance of the turbine is investigated. Finally, the evolution during the period of load rejection is characterized in order to determine the hydrodynamic conditions causing the vibrations in the machine.

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An hybrid RANS/LES model for simulation of complex turbulent flow

Cited by 20 publications

References 13 publications

A Delayed Detached Eddy Simulation Model for the Simulation of Complex Turbulent Flow

A Delayed Detached Eddy Simulation Model for the Simulation of Complex Turbulent Flow

Numerical Prediction on Vibration and Noise Reduction Effects of Propeller Boss Cap Fins on a Propulsion System

Numerical Study on the Internal Flow Field of a Reversible Turbine during Continuous Guide Vane Closing

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