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.
Highlights
Aerodynamic noise of high-speed train is an outstanding factor that restricts China’s stepping outside into world with the increase of operation speed [1, 2]
A smooth design can control the aerodynamic noise level of train body to a large extent; this inversely increases the contribution ratio of noise of unsmoothed components, such as pantograph and bogies, making them the main noise sources. e test results obtained from a real-train running at 330 km/h indicate that the contribution rates of radiation noise from pantograph accounts to more than 10% of the total noise
Lee et al [17] discussed the contributions of components of a closed-type pantograph to the aeroacoustic spectrum under 400 km/h by means of an large eddy simulation (LES) model and the Ffowcs Williams– Hawkings (FW-H) equation; they revealed that noise within the frequency bands of 60–400, 600–800, 1000–2000, and 2000–5000 Hz was mainly derived from the bottom frame area, panhead area, knuckle area between the upper and lower arms, and whole pantograph, respectively
Summary
Key Laboratory of Traffic Safety on Track (Central South University), Ministry of Education, School of Traffic and Transportation Engineering, Central South University, Changsha 410075, Hunan, China. Based on the computation precision of the five models, a feasible turbulent model was selected for simulating aerodynamic noise. E 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. 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. 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. 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. e numerical computation model was verified using the wind-tunnel test results
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