Jianyue Zhu

Bio: Jianyue Zhu is an academic researcher from University of Southampton. The author has contributed to research in topics: Bogie & Aerodynamics. The author has an hindex of 6, co-authored 10 publications receiving 153 citations. Previous affiliations of Jianyue Zhu include Tongji University.

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Abstract: At speeds above 300–350 km/h, the main source of noise from trains is the aerodynamic noise caused by the air flow over the train structure. The sound level increases with train speed at a rate of between 60 and 80 times the logarithm of the speed so that, as speeds increase further, the noise increases dramatically. The main aerodynamic noise is produced by the air flow passing over the pantograph, the train nose, the bogie region and cavities such as the pantograph recess and the inter-coach gap. Experimental and numerical methods for studying aerodynamic noise are reviewed including the use of microphone arrays, wind tunnels, computational fluid dynamics and semi-empirical methods. Potential mitigation measures that can control aerodynamic noise are also reviewed.

Flow behaviour and aeroacoustic characteristics of a simplified high-speed train bogie

Abstract: Aerodynamic noise becomes significant for high-speed trains and its prediction in an industrial context is difficult to achieve. The aerodynamic and aeroacoustic behaviour of the flow past a simplified high-speed train bogie at scale 1:10 is studied using a two-stage hybrid method comprising computational fluid dynamics and acoustic analogy. The near-field unsteady flow is obtained by solving the Navier-Stokes equations numerically with the delayed detached-eddy model and the results are used to predict the far-field noise through the Ffowcs Williams-Hawkings method. The sound radiated from the same scaled bogie model is measured in an anechoic open-jet wind tunnel. The aeroacoustic characteristics of tandem wheelsets are also investigated for comparison. It is found that the unsteady flow past the bogie is characterized by coherently alternating vortex shedding from the axles and more randomly distributed vortices of various scales and orientations from the wheels and frame. The vortices formed behind the upstream geometries are convected downstream and impinge on the downstream bodies, generating a highly turbulent wake behind the bogie. The noise predictions correspond fairly well with the experimental measurements for the dominant frequency of tonal noise and the shape of spectra. Vortex shedding from the axles generates the tonal noise with the dominant peak corresponding to the vortex shedding frequency. The directivity exhibits a dipole shape for the noise radiated from the bogie. Compared to the wheelsets of the bogie, the noise contribution from the bogie frame is relatively weaker.

Flow simulation and aerodynamic noise prediction for a high-speed train wheelset

Abstract: Aerodynamic noise becomes significant for high-speed trains and its prediction in an industrial context is hard to achieve. The aerodynamic and aeroacoustic behaviour of the flow past a high-speed train wheelset, one of the main components of a bogie, are investigated at a scale 1:10 using a two-stage hybrid method of computational fluid dynamics and acoustic analogy. The near-field unsteady flow is obtained by solving the Navier-Stokes equations numerically through delayed detached-eddy simulations and the results are fed to predict the far-field noise signals using the Ffowcs Williams-Hawkings acoustic analogy. Far-field sound radiated from the scaled model is also measured in a low noise open-jet anechoic wind tunnel. Good agreement is achieved between numerical and experimental results for the dominant frequency of tonal noise and the shape of the spectra. Results show that turbulent flow past the wheelset is characterized by three-dimensional streamwise and spanwise vortices with various scales and o...

Analysis of Aerodynamic and Aeroacoustic Behaviour of a Simplified High-Speed Train Bogie

Abstract: As one of the main aerodynamic noise sources of high-speed trains, the bogie is a complex structure containing many components and the flow around it is extremely dynamic with high-level turbulence. Flow around a simplified bogie at scale 1:10 is studied numerically using computational fluid dynamics for comparison with experimental measurements. The upstream inlet flow is represented as a steady uniform flow of low turbulence level in the simulations. Following a rigorous grid refinement study, multi-block fully structured meshes are generated for all cases to improve numerical efficiency and accuracy. The aerodynamic and aeroacoustic behaviour of the flow past an isolated wheelset, tandem wheelsets and a simplified bogie are investigated.

Recent developments in the prediction and control of aerodynamic noise from high-speed trains

Abstract: At speeds above 300–350 km/h, the main source of noise from trains is the aerodynamic noise caused by the air flow over the train structure. The sound level increases with train speed at a rate of between 60 and 80 times the logarithm of the speed so that, as speeds increase further, the noise increases dramatically. The main aerodynamic noise is produced by the air flow passing over the pantograph, the train nose, the bogie region and cavities such as the pantograph recess and the inter-coach gap. Experimental and numerical methods for studying aerodynamic noise are reviewed including the use of microphone arrays, wind tunnels, computational fluid dynamics and semi-empirical methods. Potential mitigation measures that can control aerodynamic noise are also reviewed.

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