Yinyu Tang^1,2,3,*, Mingzhi Yang^1,2,3

The International Conference on Computational & Experimental Engineering and Sciences, Vol.33, No.2, pp. 1-1, 2025, DOI:10.32604/icces.2025.011292

Abstract Energy efficiency and environmental sustainability in rail transit are key engineering goals. In urban trains, pressure drag plays a more significant role than in high-speed EMUs, primarily due to the blunt shape of the train’s head. The constraints imposed by underground construction and engineering protocols prevent the optimization strategies used in high-speed EMUs from being applied to urban trains. Therefore, aerodynamic drag reduction in blunt-tail urban trains, through active wake flow control, holds promise for improving train aerodynamics.
This study investigates drag reduction on the tail car of blunt urban trains using a hybrid numerical and… More >

Jichao Li, Xuexin Zhu, Cong Zhang, Shiwang Dang, Guang Chen^*

FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.9, pp. 2305-2329, 2025, DOI:10.32604/fdmp.2025.067087 - 30 September 2025

Abstract The rapid advancement of technology and the increasing speed of vehicles have led to a substantial rise in energy consumption and growing concern over environmental pollution. Beyond the promotion of new energy vehicles, reducing aerodynamic drag remains a critical strategy for improving energy efficiency and lowering emissions. This study investigates the influence of key geometric parameters on the aerodynamic drag of vehicles. A parametric vehicle model was developed, and computational fluid dynamics (CFD) simulations were conducted to analyse variations in the drag coefficient () and pressure distribution across different design configurations. The results reveal that More >

Huihui Zhai¹, Dongqi Jiao², Haichao Zhou^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.1, pp. 955-975, 2024, DOI:10.32604/cmes.2023.043322 - 30 December 2023

Abstract The wheels have a considerable influence on the aerodynamic properties and can contribute up to 25% of the total drag on modern vehicles. In this study, the effect of the wheel spoke structure on the aerodynamic performance of the isolated wheel is investigated. Subsequently, the 35° Ahmed body with an optimized spoke structure is used to analyze the flow behavior and the mechanism of drag reduction. The Fluent software is employed for this investigation, with an inlet velocity of 40 m/s. The accuracy of the numerical study is validated by comparing it with experimental results obtained… More >

Amer A. Abdulrahman¹, Bashar J. Kadhim¹, Zainab Y. Shnain¹, Hassan Sh. Majidi², Asawer A. Alwaiti^1,*, Farooq Al-Sheikh¹, Adnan A. AbdulRazak¹, Mohammed Shorbaz¹, Mazin J. Shibeeb³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2579-2595, 2023, DOI:10.32604/fdmp.2023.027454 - 25 June 2023

Abstract The well-known frictional effect related to liquid-liquid two-phase flow in pipelines can be reduced using drag-reducing additives. In this study, such an effect has been investigated experimentally using a mixture of oil and water. Moreover, numerical simulations have been carried out using the COMSOL simulation software. The measurements were taken in a horizontal pipe with the length and diameter equal to 3 and 0.125 m, respectively. Moreover, Polyethylene oxide with 150 ppm was exploited to reduce the drag effect while considering different water-to-oil fractions (0.3, 0.4, 0.5, and 0.7) and a constant total flow velocity More >

Lanqi Chen, Yuwei Wang, Cong Qi^*, Zhibo Tang, Zhen Tian

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1205-1227, 2022, DOI:10.32604/fdmp.2022.021200 - 27 May 2022

Abstract Nowadays, the utilization rate of electronic products is increasing while showing no obvious sign of reaching a limit. To solve the associated “internal heat generation problem”, scientists have proposed two methods or strategies. The first approach consists of replacing the heat exchange medium with a nanofluid. However, the high surface energy of the nanoparticles makes them prone to accumulate along the heat transfer surface. The second method follows a different approach. It tries to modify the surface structure of the electronic components in order to reduce the fluid-dynamic drag and improve the rate of heat More > Graphic Abstract

Mingjun Du^1,2, Jiaqiang Jing^1,*, Xinqiang Xiong³, Bingbing Lang², Xuan Wang², Shiying Shi^4,*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.1, pp. 81-91, 2022, DOI:10.32604/fdmp.2022.016640 - 10 November 2021

Abstract Transportation of heavy oil by the so-called water-ring technique is a very promising method by which pressure drop and pollution can be significantly reduced. Dedicated experiments have been carried out by changing the phase’s density, viscosity, velocity and interfacial tension to systematically analyze the characteristics of the water ring. On the basis of such experimental data, a mathematical model for pressure drop prediction has been introduced. This research shows that as long as the density of oil and water remains the same, a concentric water ring can effectively be formed. In such conditions, the oil-water More >

Jiawei Jiang, Yizhou Shen^*, Jie Tao^*, Zhenfeng Jia, Xinyu Xie, Chaojiao Zeng

Journal of Renewable Materials, Vol.10, No.3, pp. 781-797, 2022, DOI:10.32604/jrm.2022.017230 - 28 September 2021

Abstract A new type of microstructure inspired by the cross section of barchan dunes was proposed to reduce windage, which was considered as a passive drag reduction technology in aerospace manufacturing field. Computational fluid dynamics method was carried out to discuss the effect of the microstructure on the skin friction reduction under high velocity flow condition. Different microstructure heights were employed to survey the reduction of drag. The results illustrated that the appearance of microstructure led to a generation of pressure drag in non-smooth model (with microstructures inspired by cross section of barchan dune) in contrast… More > Graphic Abstract

Wei Tian^a , Mingjun Pang^a,*, Na Xu^b,†

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-12, 2021, DOI:10.5098/hmt.16.13

Abstract Drag reduction (DR) by the additive of mixed surfactant and polymer is investigated in detail in a rotating disk apparatus (RDA). Polyethylene oxide (PEO) and Cetyltrimethyl ammonium chloride (CTAC)/sodium salicylate (NaSal) are chosen as polymer and surfactant, respectively. It is investigated on the influence of combination concentration of polymer & surfactant, temperature and Reynolds number on the drag-reducing rate. The present experimental results show that the drag-reducing rate of the mixed solution is definitely higher than that of the pure PEO or CTAC/NaSal solutions. This phenomenon is especially sharp at the high temperature and/or the… More >

Zihai Geng^1,2,*, Jinsheng Cai¹, Yubiao Jiang^1,2, Weiguo Zhang^1,2

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.5, pp. 899-915, 2021, DOI:10.32604/fdmp.2021.012108 - 05 July 2021

Abstract Reducing drag during take-off and nominal (cruise) conditions is a problem of fundamental importance in aeronautical engineering. Existing studies have demonstrated that v-shaped symmetrical riblets can effectively be used for turbulence control, with those with dimensionless depth h⁺ = 15 and dimensionless width s⁺ = 15 having the best drag reduction effect. In the present study, experimental tests have been conducted considering two models of the same size, one with smooth surface, the other with v-shaped riblets of the h⁺ = 15 and s⁺ = 15 type. The results show that for an angle of attack in More >

Jingfa Li¹, Bo Yu^1,*, Qianqian Shao², Dongliang Sun¹

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.2, pp. 541-563, 2020, DOI:10.32604/cmes.2020.011835 - 12 October 2020

Abstract In this work, the drag-reducing mechanism of high-Reynoldsnumber turbulent channel flow with surfactant additives is investigated by using large eddy simulation (LES) method. An N-parallel finitely extensible nonlinear elastic model with Peterlin’s approximation (FENE-P) is used to describe the rheological behaviors of non-Newtonian fluid with surfactant. To close the filtered LES equations, a hybrid subgrid scale (SGS) model coupling the spatial filter and temporal filter is applied to compute the subgrid stress and other subfilter terms. The finite difference method and projection algorithm are adopted to solve the LES governing equations. To validate the correctness More >