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  • Open Access

    ARTICLE

    Numerical Analysis of the Tunnel-Train-Air Interaction Problem in a Tunnel with a Double-Hat Oblique Hood

    Zongfa Zhang1, Minglu Zhang1,*, Xinbiao Xiao2

    FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 345-359, 2023, DOI:10.32604/fdmp.2022.020233

    Abstract The tunnel-train-air interaction problem is investigated by using a numerical method able to provide relevant information about pressure fluctuations, aerodynamic drag characteristics and the “piston wind” effect. The method relies on a RNG k-ε two-equation turbulence model. It is shown that although reducing the oblique slope can alleviate the pressure gradient resulting from initial compression waves at the tunnel entrance, the pressure fluctuations in the tunnel are barely affected; however, a large reduction of micro-pressure wave amplitudes is found outside the tunnel. In comparison to the case where no tunnel hood is present, the amplitudes More > Graphic Abstract

    Numerical Analysis of the Tunnel-Train-Air Interaction Problem in a Tunnel with a Double-Hat Oblique Hood

  • Open Access

    ARTICLE

    A Numerical Investigation on the Influence of the Circular Ring on the Aerodynamic Noise Generated by a Cooling Fan

    Jun Feng1,2, Tao Bian1,2,5, Qianpeng Han2, Bing Wang1,3,4,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.1, pp. 1-14, 2023, DOI:10.32604/fdmp.2023.018275

    Abstract The influence of the width of the circular ring of a car cooling fan on the aerodynamic noise is investigated numerically through the determination of the overall sound pressure level (OASPL). The results demonstrate that when the circular rings cover near 2/3 of the width of the blade tips of the rotor in the axis direction, the rotor has the lowest OASPL and the related total pressure efficiency and flow mass rate are better than the corresponding values obtained for a reference rotor without a circular ring. With increasing the width of the circular ring More > Graphic Abstract

    A Numerical Investigation on the Influence of the Circular Ring on the Aerodynamic Noise Generated by a Cooling Fan

  • Open Access

    ARTICLE

    Numerical Simulation Research on Static Aeroelastic Effect of the Transonic Aileron of a High Aspect Ratio Aircraf

    Hongtao Guo, Changrong Zhang, Binbin Lv, Li Yu*

    CMES-Computer Modeling in Engineering & Sciences, Vol.132, No.3, pp. 991-1010, 2022, DOI:10.32604/cmes.2022.020638

    Abstract The static aeroelastic effect of aircraft ailerons with high aspect ratio at transonic velocity is investigated in this paper by the CFD/CSD fluid-structure coupling numerical simulation. The influences of wing static aeroelasticity and the ‘scissor opening’ gap width between aileron control surface and the main wing surface on aileron efficiency are mainly explored. The main purpose of this paper is to provide technical support for the wind tunnel experimental model of aileron static aeroelasticity. The results indicate that the flight dynamic pressure has a great influence on the static aeroelastic effect of ailerons, and the… More >

  • Open Access

    ARTICLE

    Comparative Study of Machine Learning Modeling for Unsteady Aerodynamics

    Mohammad Alkhedher*

    CMC-Computers, Materials & Continua, Vol.72, No.1, pp. 1901-1920, 2022, DOI:10.32604/cmc.2022.025334

    Abstract Modern fighters are designed to fly at high angle of attacks reaching 90 deg as part of their routine maneuvers. These maneuvers generate complex nonlinear and unsteady aerodynamic loading. In this study, different aerodynamic prediction tools are investigated to achieve a model which is highly accurate, less computational, and provides a stable prediction of associated unsteady aerodynamics that results from high angle of attack maneuvers. These prediction tools include Artificial Neural Networks (ANN) model, Adaptive Neuro Fuzzy Logic Inference System (ANFIS), Fourier model, and Polynomial Classifier Networks (PCN). The main aim of the prediction model… More >

  • Open Access

    ARTICLE

    A Fast Approach for Predicting Aerodynamic Noise Sources of High-Speed Train Running in Tunnel

    Deng Qin1, Tian Li1,*, Honglin Wang2, Jizhong Yang3, Yao Jiang3, Jiye Zhang1, Haiquan Bi2

    CMES-Computer Modeling in Engineering & Sciences, Vol.130, No.3, pp. 1371-1386, 2022, DOI:10.32604/cmes.2022.018480

    Abstract The aerodynamic noise of high-speed trains passing through a tunnel has gradually become an important issue. Numerical approaches for predicting the aerodynamic noise sources of high-speed trains running in tunnels are the key to alleviating aerodynamic noise issues. In this paper, two typical numerical methods are used to calculate the aerodynamic noise of high-speed trains. These are the static method combined with non-reflective boundary conditions and the dynamic mesh method combined with adaptive mesh. The fluctuating pressure, flow field and aerodynamic noise source are numerically simulated using the above methods. The results show that the More >

  • Open Access

    ARTICLE

    Numerical Investigation on the Aerodynamic Noise Generated by a Simplified Double-Strip Pantograph

    Jiawei Shi1, Shuai Ge1, Xiaozhen Sheng2,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.2, pp. 463-480, 2022, DOI:10.32604/fdmp.2022.017508

    Abstract In order to understand the mechanism by which a pantograph can generate aerodynamic noise and grasp its far-field characteristics, a simplified double-strip pantograph is analyzed numerically. Firstly, the unsteady flow field around the pantograph is simulated in the frame of a large eddy simulation (LES) technique. Then the location of the main noise source is determined using surface fluctuating pressure data and the vortex structures in the pantograph flow field are analyzed by means of the Q-criterion. Based on this, the relationship between the wake vortex and the intensity of the aerodynamic sound source on… More >

  • Open Access

    ARTICLE

    Parameter Scaling of the Aerodynamic Breakup of the Acoustic Levitated Droplets in an Air Jet Flow

    Yanju Wei1,*, Shengcai Deng1, Jie Zhang1, Yajing Yang2, Hao Chen3

    Energy Engineering, Vol.118, No.2, pp. 225-235, 2021, DOI:10.32604/EE.2021.012416

    Abstract The aerodynamic breakup of the droplet has been intensely studied in this paper. We aim to establish a unified relationship between dimensionless kinematic parameters such as displacement, spreading diameter, Weber number, time, and so on. The breakup characteristics of the acoustic levitated ethanol droplet are experimentally investigated when exposed to an air jet flow. The breakup phenomenons were recorded with a high-speed camera. The breakup characteristics were analyzed, and the physical models of the moving and transforming behaviors were established to explain the breakup mechanisms. We found that the displacement of the windward side of More >

  • Open Access

    ARTICLE

    Effects of Heaving Motion on the Aerodynamic Performance of a Double-Element Wing in Ground Effect

    Ioannis Oxyzoglou*, Zheng-Tong Xie

    FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.6, pp. 1093-1114, 2020, DOI:10.32604/fdmp.2020.012237

    Abstract The broad implication of the paper is to elucidate the significance of the dynamic heaving motion in the aerodynamic performance of multi-element wings, currently considered as a promising aspect for the improvement of the aerodynamic correlation between CFD, wind tunnel and track testing in race car applications. The relationship between the varying aerodynamic forces, the vortex shedding, and the unsteady pressure field of a heaving double-element wing is investigated for a range of mean ride heights, frequencies, and amplitudes, using a two-dimensional (2D) unsteady Reynolds-averaged Navier-Stokes (URANS) approach and an overset mesh method for modelling… More >

  • Open Access

    ARTICLE

    Effects of Wall Emissivity on Aerodynamic Heating in Scramjets

    Yue Zhou1, Pengfei Ju2,3,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.6, pp. 1273-1283, 2020, DOI:10.32604/fdmp.2020.09666

    Abstract The effects of the wall emissivity on aerodynamic heating in a scramjet are analyzed. The supersonic turbulent combustion flow including radiation is solved in the framework of a decoupled strategy where the flow field is determined first and the radiation field next. In particular, a finite difference method is used for solving the flow while a DOM (iscrete ordinates method) approach combined with a WSGGM (weighted sum of gray gases) model is implemented for radiative transfer. Supersonic nonreactive turbulent channel flows are examined for a DLR hydrogen fueled scramjet changing parametrically the wall emissivity. The More >

  • Open Access

    ARTICLE

    Numerical Study of High-Temperature Nonequilibrium Flow around Reentry Vehicle Coupled with Thermal Radiation

    Jingying Wang, Fangzhou Han*, Li Lei, Chunhian Lee

    FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.3, pp. 601-613, 2020, DOI:10.32604/fdmp.2020.09624

    Abstract Accurate aerodynamic heating prediction is of great significance to current manned space flight and deep space exploration missions. The temperature in the shock layer surrounding the reentry vehicle can reach up to 10,000 K and result in remarkable thermochemical nonequilibrium, as well as considerable radiative heat transfer. In general, high-temperature flow simulations coupled with thermal radiation require appropriate numerical schemes and physical models. In this paper, the equations governing hypersonic nonequilibrium flow, based on a three-temperature model combined with a thermal radiation solving approach, are used to investigate the radiation effects in the reentry shock… More >

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