| 1. |
- Wu, Yitong, et al.
(författare)
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Numerical and experiment study on ventilation performance of the equipment compartment of Alpine high-speed train
- 2023
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Ingår i: Engineering Applications of Computational Fluid Mechanics. - 1994-2060 .- 1997-003X. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Alpine High-Speed Train serves on the Lanzhou-Urumqi Line in northwest China, where the terrain is mainly the Gobi Desert. To adapt to this complex environment, the independent-air duct is mainly used for the electrical facilities inside the equipment compartment to prevent the spread of sand particles. This isolated air duct makes ventilation characteristics of the equipment susceptible to the external environment. For this reason, this work aims to clarify and investigate the ventilation characteristic of electrical facilities. A two-step simulation method using IDDES (Improved Delayed Detached Eddy Simulation) and a real-vehicle tracking test using the T-typed pitot tubes were conducted. In the simulation, it is found that the ventilation performance can be influenced by the location of the equipment compartment, facilities and the fan mounted inside. By comparing the results of the test and simulation, they share the same characteristic that the air outlet volume of the converter near the head car is being promoted while it near the tail car is being inhibited. The maximum deviation ratio between the test and simulation is 9%. Therefore, the measurement method in this study is relatively reliable.
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| 2. |
- Xu, Kewei, 1992, et al.
(författare)
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Active flow control of the airflow of a ship at yaw
- 2023
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018. ; 273
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Tidskriftsartikel (refereegranskat)abstract
- This paper implements the steady Coanda effect active flow control (AFC) on the Chalmers ship model (CSM) to study its influence on the ship's side force and airwake under the yaw effect. The study is conducted numerically using Large Eddy Simulation (LES) with Wall-Adapting Local-Eddy Viscosity (WALE) model. Numerical methods are validated by the experimental data acquired from the baseline CSM under 10∘ port-side wind. The model with AFC is created by modifying the square-shaped hanger base to the Coanda surface and added with injection slots along the base's roof edge and two side edges. The results show that the base-shape modification significantly alters the vortex structure on deck from z-direction vortex (ZV) to streamwise vortex (SV), and the steady Coanda effect with a momentum coefficient (Cμ) of 0.02 further enhances the SV with the removal of port-side vortex (PV). The side force and yaw moment are reduced by 5.27% and 7.97%, respectively in the AFC case due to the reduction of port-side (windward) ship-surface pressure. Furthermore, the current AFC can suppress the low-speed region and alleviate the velocity gradient in the lateral direction, which mitigates the regions of high TKE (turbulent kinetic energy) and high shear stress along the port-side deck.
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