Haiqing Li¹, Mengge Yu^{1, *}, Qian Zhang¹, Heng Wen¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 77-90, 2020, DOI:10.32604/fdmp.2020.07797

Abstract The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years. The objective of the present paper was to investigate the aerodynamic characteristics of a high-speed train under such conditions in the framework of an Eulerian-Lagrangian approach. An aerodynamic model of a high-speed train was first set up, and the side force coefficient obtained from numerical simulation was compared with that provided by wind tunnel experiments to verify the accuracy of the approach. Then, the effects of the yaw angle, the resultant wind speed, and the rainfall rate on… More >

Xiaohan Zhang¹, Yao Jiang², Tian Li^{1, *}

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 67-76, 2020, DOI:10.32604/fdmp.2020.07776

Abstract The aerodynamic resistance of a train running in the open air limits the maximum speed that can be attained by the train. For this reason, evacuated tube trains (ETT) are being considered as valid alternatives to be implemented in the future. The atmosphere in the tube, the so-called blocking ratio and the length of the streamlined nose are the key factors affecting the aerodynamic performances of these trains. In the present work, we investigate evacuated tube trains with different lengths of the streamline nose on the basis of computational fluid dynamics (CFD). The three-dimensional steady compressible Navier-Stokes equations are solved.… More >

Mengge Yu^{1, 2}, Zhenkuan Pan^{3, *}, Jiali Liu⁴, Haiqing Li¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 55-66, 2020, DOI:10.32604/fdmp.2020.07774

Abstract The operational safety characteristics of trains exposed to a strong wind have caused great concern in recent years. In the present paper, the effect of the strong gust wind on a high-speed train is investigated. A typical gust wind model for any wind angle, named “Chinese hat gust wind model”, was first constructed, and an algorithm for computing the aerodynamic loads was elaborated accordingly. A vehicle system dynamic model was then set up in order to investigate the vehicle system dynamic characteristics. The assessment of the operational safety has been conducted by means of characteristic wind curves (CWC). As some… More >

Lu Cai¹, Zhen Lou¹, Nan Liu², Chao An², Jiye Zhang^{1, *}

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 41-53, 2020, DOI:10.32604/fdmp.2020.07731

Abstract To investigate the deposition distribution of snow particles in the bogie surfaces of a high-speed train, a snow particle deposition model, based on the critical capture velocity and the critical shear velocity, was elaborated. Simulations based on the unsteady Reynolds-Averaged Navier-Stokes (RANS) approach coupled with Discrete Phase Model (DPM) were used to analyze the motion of snow particles. The results show that the cross beam of the bogie frame, the anti-snake damper, the intermediate brake clamps in the rear wheels, the traction rod and the anti-rolling torsion bar are prone to accumulate snow. The accumulation mass relating to the vertical… More >

Zhiyuan Dai¹, Tian Li^{1, *}, Weihua Zhang¹, Jiye Zhang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 31-40, 2020, DOI:10.32604/fdmp.2020.07661

Abstract Pantograph is a critical component of the high-speed train. It collects power through contact with catenary, which significantly affects the running safety of the train. Pantograph with double collector strips is one common type. The aerodynamic performance of the collector strips may affect the current collection of the pantograph. In this study, the aerodynamic performance of the pantograph with double strips is investigated. The numerical results are consistent with the experimental ones. The error in the aerodynamic drag force of the pantograph between numerical and experimental results is less than 5%. Three different conditions of the strips are studied, including… More >

Jiali Liu¹, Mengge Yu^{2, *}, Dawei Chen¹, Zhigang Yang³

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 21-30, 2020, DOI:10.32604/fdmp.2020.07658

Abstract In order to investigate how the aerodynamic drag and noise produced by the roof air conditioner of a high-speed train can be reduced, the related unsteady flow in the near-field was computed using the method of large eddy simulation. In this way, the aerodynamic source for noise generation has initially been determined. Then, the far-field aerodynamic noise has been computed in the framework of the Lighthill’s acoustics analogy theory. The propulsion height and flow-guide angle of the roof air conditioner were set as the design variables. According to the computational results, a lower propulsion height or flow-guide angle is beneficial… More >

Yundong Han¹, Dawei Chen¹, Shaoqing Liu¹, Gang Xu²

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 1-19, 2020, DOI:10.32604/fdmp.2020.06525

Abstract A series of tests have been conducted using a Cryogenic Wind Tunnel to study the effect of Reynolds number (Re) on the aerodynamic force and surface pressure experienced by a high speed train. The test Reynolds number has been varied from 1 million to 10 million, which is the highest Reynolds number a wind tunnel has ever achieved for a train test. According to our results, the drag coefficient of the leading car decreases with higher Reynolds number for yaw angles up to 30º. The drag force coefficient drops about 0.06 when Re is raised from 1 million to 10… More >

Jingyi Wang¹, Jing Sun^1,*, Dehua Liu¹, Xiang Zhu¹

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.5, pp. 613-625, 2019, DOI:10.32604/fdmp.2019.08782

Abstract One of the important indicators of shale gas reservoir excavation is capacity evaluation, which directly affects whether large-scale shale gas reservoirs can be excavated. Capacity evaluation is the basis of system analysis and dynamic prediction. Therefore, it is particularly important to conduct capacity evaluation studies on shale gas horizontal wells. In order to accurately evaluate the horizontal well productivity of shale gas staged fracturing, this paper uses a new method to evaluate the productivity of Fuling shale gas. The new method is aimed at the dynamic difference of horizontal wells and effectively analyzes the massive data, which are factors affecting… More >

Najat A. Alghamdi¹, Hamdy M. Youssef^2,3,*

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.5, pp. 597-611, 2019, DOI:10.32604/fdmp.2019.05131

Abstract A mathematical model is elaborated for a thermoelastic infinite body with a spherical cavity. A generalized set of governing equations is formulated in the context of three different models of thermoelasticity: the Biot model, also known as “coupled thermoelasticity” model; the Lord-Shulman model, also referred to as “generalized thermoelasticity with one-relaxation time” approach; and the Green-Lindsay model, also called “generalized thermoelasticity with two-relaxation times” approach. The Adomian’s decomposition method is used to solve the related mathematical problem. The bounding plane of the cavity is subjected to harmonic thermal loading with zero heat flux and strain. Numerical results for the temperature,… More >

Zhihui Wang^1,2,3, Wei Luo^1,2,3,*, Ruiquan Liao^1,2,3, Xiangwei Xie⁴, Fuwei Han⁵, Hongying Wang⁶

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.5, pp. 583-595, 2019, DOI:10.32604/fdmp.2019.06847

Abstract Horizontal well production technology gradually occupies a dominant position in the petroleum field. With the rise in water production in the later stage of exploitation, slug flow phenomena will exist in horizontal, inclined and even vertical sections of gas wells. To grasp the flow law of slug flow and guide engineering practice, the flow law of slug flow at various inclination angles (30°~90°) is studied by means of the combination of laboratory experiments (including high frequency pressure data acquisition system) and finite element numerical simulation. The results reveal that because of the delay of pressure variation at the corresponding position… More >