Adaptability of Turbulence Models for Pantograph Aerodynamic Noise Simulation

Abstract

This study was targeted at CX-PG-type Faiveley pantograph of high-speed train and cylinders and analysed the fluctuating flow field around these objects by using the large eddy simulation (LES) model, the scale adaptive simulation (SAS) model, the improved delayed detached eddy simulation with shear-stress transport-kω (IDDES sst-kω) model, the delayed detached eddy simulation with shear-stress transport-kω (DDES sst-kω) model, and the delayed detached eddy simulation with realizable-kε (DDES R-kε) model. The space distributions of velocity, vorticity, and vortex structures were compared to investigate their performances on simulating fluctuating flow fields and computing aeroacoustic sources through Fourier transformation based on the surface fluctuating pressures. Furthermore, the far-field radiated noise was calculated based on the Ffowcs Williams–Hawkings equation. Based on the computation precision of the five models, a feasible turbulent model was selected for simulating aerodynamic noise. The relative errors to the results from wind-tunnel experiments of the sound pressure level (SPL) were obtained as 0.7%, 1.6%, 7.8%, 3.8%, and 12.1%, respectively, and the peak Strouhal numbers were obtained as 2.0%, 8.5%, 5.5%, 11.5%, and 51.0% for cylinder simulation. Moreover, the relative errors of SAS, IDDES sst-kω, DDES sst-kω, and DDES R-kε models to the result from LES of SPL were respectively obtained as 2.3%, 4.5%, 5.6%, and 10.8% for pantograph. Thus, it is conclusive that none of the aforementioned models are comparable with the LES model with respect to the precision in the aeroacoustic simulation. However, SAS, IDDES sst-kω, and DDES sst-kω are practically competent with the LES model considering the numerical simulations with respect to the engineering computation precision. The numerical computation model was verified using the wind-tunnel test results.

Comparison of different configurations of aerodynamic braking plate on the flow around a high-speed train

“…The improved delayed detached eddy simulation method (IDDES) was selected to simulate the flow field in this study as this method combines the advantages of the Reynolds-Averaged Navier-Stokes framework and the Large Eddy Simulation, which have been discussed in detail (Dong et al, 2018;Gritskevich et al, 2012;Zhang et al, 2015). Finally, IDDES with SST κ-ω turbulence model was determined for simulations, and this method has been successfully applied to the simulation of train aerodynamic characteristics by numerous researchers (Chen et al, 2019;Dong et al, 2019;He et al, 2018;Li et al, 2018;Li et al, 2019;Niu et al, 2018b;Tan et al, 2019;Zhang et al, 2019;Zhou et al, 2020).…”

Numerical Study on Aerodynamic Noise Reduction of Pantograph

“…Delayed detached eddy simulation (DDES) has been widely used in turbulence and aeroacoustic simulations [18][19][20], which is employed to compute the flowfield and the acoustic source in this paper. The current DDES simulations are based on the Realizable k − model, written as follows [21]:…”

“…The free-stream condition is similar to that in Refs. [19,23]. The grid is clustered in the cylinder surface, and the value of y + is close to 1.…”

Numerical Simulation of Acoustic Resonance Enhancement for Mean Flow Wind Energy Harvester as Well as Suppression for Pipeline

“…In addition, our simulation experience shows that the pressure fluctuation results of the RANS model are easy to decay, and it is not easy to simulate the acoustic resonance phenomenon that should exist. In this paper, we used delayed detached-eddy simulation (DDES), a hybrid model of LES-RANS extended by Spalart et al [34], which is widely and effectively used [35][36][37][38][39]. Due to the advantages of accuracy and economy, the k-ε turbulence model is the most commonly used CFD model, among which the realizable k-ε model shows the best performance in simulating separated flows [40].…”