An alternative algorithm of tunnel piston effect by replacing three-dimensional model with two-dimensional model

Liu, Minzhang; Zhu, Chunguang; Cui, Tong; Zhang, Huan; Zheng, Wandong; You, Shijun

doi:10.1016/j.buildenv.2017.11.022

Cited by 43 publications

(9 citation statements)

References 26 publications

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“…To validate the effectiveness of the numerical simulation method, the motion model measurement conducted by Kim et al [44] was calculated using the above numerical simulation method [45,46], as shown in Figure 7. For detailed information on the tests, please refer to the literature of Kim et al [44].…”

Section: Validationmentioning

confidence: 99%

“…Although the train speed of the validation case is much lower than that of the current work, the comparison results indicate that the numerical method adopted in this research is accurate to simulate the moving object-induced aerodynamic pressure and unsteady flow inside a tunnel structure. In addition, Liu et al [45] and Izadi et al [46] had used a similar method to simulate the aerodynamic pressure inside tunnels and obtained reasonable results. It indicates that the numerical method adopted in this research is accurate for obtaining the main characteristics of the flow field and aerodynamic pressure fluctuation when a high-speed train passes the housing for sound emission alleviation.…”

Section: Validationmentioning

confidence: 99%

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Dynamic Characteristics of Unsteady Aerodynamic Pressure on an Enclosed Housing for Sound Emission Alleviation Caused by a Passing High-Speed Train

Jing

et al. 2022

Applied Sciences

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Train speed is increasing due to the development of high-speed railway technology. However, high-speed trains generate more noise and discomfort for residents, enclosed housing for sound emission alleviation is needed to further reduce noise. Because these enclosed housings for sound emission alleviation restrain the air flow, strong and complicated aerodynamic pressures are generated inside the housing for sound emission alleviation when a train passes through at a high speed. This train-induced aerodynamic pressure, particularly its dynamic characteristics, is a key parameter in structural design. In the present study, the train-induced unsteady aerodynamic pressure in an enclosed housing for sound emission alleviation is simulated using the dynamic mesh method, and the dynamic characteristics of the aerodynamic pressure are investigated. The simulation results show that when the train is running in the enclosed housing for sound emission alleviation, the unsteady aerodynamic pressure is complicated and aperiodic, and after the train leaves the housing for sound emission alleviation, the aerodynamic pressure reverts to periodic decay curves. Two new terms, the duration of the extreme aerodynamic pressure and the pressure change rate, are proposed to evaluate the dynamic characteristics when the train passes through the barrier. The dominant frequency and decay rate are adopted to express the dynamic characteristics after the train exits. When the train runs in the enclosed housing for sound emission alleviation, the longest durations of the positive and negative extreme aerodynamic pressures are in the middle section, and the maximum change rate of aerodynamic pressure occurs at the entrance area. After the train exits the housing for sound emission alleviation, the pressure amplitude at the central region is always higher than those close to the entrance/exit. The dominant frequency of the aerodynamic pressure is identified and explained using wave propagation theory, the decay rate of the aerodynamic pressure at all sections is close.

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Section: Validationmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Dynamic Characteristics of Unsteady Aerodynamic Pressure on an Enclosed Housing for Sound Emission Alleviation Caused by a Passing High-Speed Train

Jing

et al. 2022

Applied Sciences

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“…The moving zone slides over stationary zone at a defined velocity. Yang et al [13], Khayrullina et al [14] and Chen et al [15] applied the sliding mesh technique, while Huang et al [16], Liu et al [17], Zhang et al [18] and Izadi et al [19] applied the dynamic mesh technique. In this technique, the shape of the domain is changing with time due to the domain moving boundaries.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effects of different parameters on the generated pressure waves inside the tunnels

et al. 2020

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In this research the train movement along the tunnel was simulated numerically, and the time evolution of the flow field in the tunnel was evaluated. The unsteady forms of continuity, Navier-Stokes, and energy equations were applied to solve the compressible viscous flow using the dynamic mesh technique. The importance of using a compressible flow model, even for the low Mach number flow case, was demonstrated. It was shown that even in low train speeds; a compressible model is preferred, as it can predict the pressure fluctuations, while an incompressible model may only be used for predicting the mean pressure. However, in cases where pressure fluctuations are not important, the incompressible model can be used especially for a train with low acceleration. When the trains accelerate, it was found that the initial slope of the pressure curve is proportional to the train acceleration. Therefore, the increase in the train acceleration increases the maximum pressure rise. Also, the first pressure rise depends on the velocity of the train tail as it enters the tunnel. In addition, the earlier equations in the literature for computing the maximum pressure rise, can properly predict the pressure rise of accelerating trains if the train tail velocity, as it enters the tunnel, is used as the velocity scale.

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“…The dynamic mesh technique in Fluent can realize the train's movement in the numerical simulation, so researchers adopted it to predict the airflow induced by the moving train in a tunnel [13][14][15][16][17]. In addition, Liu et al [18] used a two-dimensional model to simulate and study the three-dimensional flow of piston wind in a tunnel. A great deal of research shows that the piston effect greatly influences comfort, efficiency of the ventilation system and energy savings [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Behavior of Piston Wind Induced by Braking Train in a Tunnel

et al. 2020

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It is critical to discover the behavior of piston wind induced by a braking train in a tunnel, but there is little research on the theoretical derivation for piston wind behavior. Predicting piston wind behavior as an unsteady airflow by a theoretical formula is hard work due to the complexity of train running states and airflow fields. Herein, we develop a mathematical model to investigate the behavior of piston wind as an unsteady airflow, considering the variation of wind direction in the annular area. In general, the theoretical model is validated by experiments. However, experimental studies about piston wind are scarce. In this study, we simulated the emergent braking process of a train to validate the mathematical model by establishing a 1/50 scaled experimental configuration. The piston wind data tested in the experiment have good agreement with the results calculated by theoretical formulas. In addition, sensitivity analysis of the effect parameters of piston wind (i.e., tunnel length, train length, train speed and blockage ratio) was conducted. The theoretical formulas derived in this paper are applicable to similar train running conditions in railway tunnels or subway tunnels.

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An alternative algorithm of tunnel piston effect by replacing three-dimensional model with two-dimensional model

Cited by 43 publications

References 26 publications

Dynamic Characteristics of Unsteady Aerodynamic Pressure on an Enclosed Housing for Sound Emission Alleviation Caused by a Passing High-Speed Train

Dynamic Characteristics of Unsteady Aerodynamic Pressure on an Enclosed Housing for Sound Emission Alleviation Caused by a Passing High-Speed Train

Investigation of the effects of different parameters on the generated pressure waves inside the tunnels

Behavior of Piston Wind Induced by Braking Train in a Tunnel

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