The performance of different turbulence models (URANS, SAS and DES) for predicting high-speed train slipstream

Wang, Shibo; Bell, James; Burton, David; Herbst, Astrid H.; Sheridan, John; Thompson, Mark C.

doi:10.1016/j.jweia.2017.03.001

Cited by 130 publications

(52 citation statements)

References 23 publications

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“…The zonal methods separate the near wall region (resolved using a RANS model) and the outer regions (where LES is used) by a distinct interface (also see Jakirlic and Maduta (2015)), while the non-zonal methods seamlessly bridge the two regions. The comparison/assessment between various turbulence models for canonical/simplistic bluff bodies has been widely reported (Guilmineau et al (2017), Maleki et al (2017), Serre et al (2013) and others); more realistic geometries have also been assessed (Wang et al (2017), Jakirlic et al (2017a), Jakirlic et al (2017b), , Ashton et al (2016) and Pereira et al (2018a)). It may be noted that different methodologies/closure models for turbulence have been proposed over the past few years, and only the major models are mentioned here.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Rao

Minelli

Zhang

et al. 2018

Journal of Wind Engineering and Industrial Aerodynamics

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The near-wake flow topology of a ground transportation system (GTS) is investigated using partially-averaged Navier-Stokes (PANS) simulations at Re ¼ 2:7 Â 10 4. Recent numerical investigations for the GTS model using large eddy simulations (LES) showed an anti-symmetric flow topology (flow state II) in the vertical midplane compared to that observed in previous experimental studies (flow state I). The geometrical configuration of the GTS permits bi-stable behaviour, and the realisation of each of the two flow states, which are characterised by an asymmetrical flow topology, is achieved by varying the differencing scheme for the convective flux in the PANS simulations; AVL SMART schemes predict flow state I, while central differencing scheme (CDS) predicts flow state II. When the GTS model was placed away from the ground plane, the AVL SMART scheme fails to predict the flow asymmetry resulting in a pair of symmetrical vortices in the vertical midplane, while flow state II topology is observed when CDS is used. The switch from flow state I (II) to flow state II (I) is achieved by changing the numerical scheme from AVL SMART (CDS) to CDS (AVL SMART), with an intermediate transient-symmetric (TS) state being observed during the switching process. The numerical scheme in the PANS simulations thus plays a critical role in determining the initial flow topology in the near wake of the GTS.

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Section: Introductionmentioning

confidence: 99%

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Rao

Minelli

Zhang

et al. 2018

Journal of Wind Engineering and Industrial Aerodynamics

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show abstract

“…Figure 4 (a) and (b) shows the time-averaged vorticity contours and velocity vectors at the plane x/W=1 in the wake of simplified model and complex model, respectively. It can be noted that a dominating pair of counter-rotating streamwise vortices, well-established in literature [1][2][3][5][6][7]13,14], exists in both configurations. The vortex pair moves downwards and outwards in the wake.…”

Section: Numerical Validationmentioning

confidence: 54%

“…Additionally, CFD provides much more detailed information of the flow, which is helpful for understanding the inherent physics and mechanism of the issues concerned [4]. A systematic comparison of accuracy of different turbulence models applied to slipstream prediction of a HST has been conducted by Wang [5] , which shows that IDDES presents superior consistency with the experimental data in the predicting slipstream. Muld applied Proper Orthogonal Decomposition (POD) to study the flow structure of the Aerodynamic Train Model (ATM) with bogie section under the body and two different flow structures are extracted in the wake of the ATM, namely vortex shedding and bending of the counter-rotating vortices [6] .…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Effect of Underbody Configurations on the Wake of a High-speed Train

Zhou¹,

Xia²,

Zheng³

et al. 2017

dtetr

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The effect of underbody configurations on the wake of a high-speed train (HST) is numerically investigated with improved delayed detached eddy simulation (IDDES). There are two train models which are different in underbody configuration, i.e., complex train with bogie sections and simplified train with flat underbody. Both time-averaged and instantaneous wake structures are compared for the two underbody configurations. For both underbody configurations, a pair of counterrotating streamwise vortices exists in the wake. The vortex pair of the complex train oscillates more violently along the spanwise direction, leading to a wider wake than that of the simplified train. In addition, each of the vortex pair appears alternatively in the wake of the complex train, while the wake of simplified train presents simultaneous coupled vortex pair. The difference in the wake of the two underbody configurations can be attributed to the effect of bogie sections.

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“…At present, numerous scholars have used the IDDES (based on the k-ω shear-stress transport turbulence model) method to study the unsteady aerodynamic performance around a train. For example, Wang et al [21] compared the accuracy of different turbulence models in predicting the slipstream. The results show that the slipstream velocity obtained with the IDDES method has good consistency with experimental data.…”

Section: Methodsmentioning

confidence: 99%

Impact of Different Nose Lengths on Flow-Field Structure around a High-Speed Train

Guang

Zhou

et al. 2019

Applied Sciences

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In this study, the time-averaged and instantaneous slipstream velocity, time-averaged pressure, wake flows, and aerodynamic force of a high-speed train (HST) with different nose lengths are compared and analyzed using an improved delayed detached-eddy simulation (IDDES) method. Four train models were selected, with nose lengths of 4, 7, 9, and 12 m. To verify the accuracy of the numerical simulation results, they were compared with wind tunnel test results. The comparison results show that the selection of the numerical simulation method is reasonable. The research results show that with increasing nose length, the peak values of the time-averaged slipstream velocity of the trackside position (3 m from the center of track and 0.2 m from the top of rail) and the platform position (3 m from the center of track and 0.2 m from the top of rail) decrease continuously, and show a trend of rapid reduction at first, and then a slow decrease. As the nose length increased from 4 to 12 m, the time-averaged slipstream velocity at the trackside position and platform position are decreased by 57% and 19.5%, respectively. At a height of 1.6 m from the top of the rail, ΔCP max (maximum pressure coefficient), |ΔCP min| (the absolute value of minimum pressure coefficient), and ΔCP (pressure change coefficient) decrease with increasing nose length, which is similar to the peak value of time-averaged slipstream velocity, decreasing rapidly at first and then slowly. As the nose length increased from 4 to 12 m, decreases of ΔCP max, |ΔCP min|, and ΔCP by 26.5%, 58.5%, and 44.8% were shown, respectively. Different nose lengths also have a significant impact on wake flow.

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The performance of different turbulence models (URANS, SAS and DES) for predicting high-speed train slipstream

Cited by 130 publications

References 23 publications

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Numerical Study on the Effect of Underbody Configurations on the Wake of a High-speed Train

Impact of Different Nose Lengths on Flow-Field Structure around a High-Speed Train

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