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Search Results (15)
  • Open Access


    The Effect of Lateral Offset Distance on the Aerodynamics and Fuel Economy of Vehicle Queues

    Lili Lei*, Ze Li, Haichao Zhou, Jing Wang, Wei Lin

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.1, pp. 147-163, 2024, DOI:10.32604/fdmp.2023.030158

    Abstract The vehicle industry is always in search of breakthrough energy-saving and emission-reduction technologies. In recent years, vehicle intelligence has progressed considerably, and researchers are currently trying to take advantage of these developments. Here we consider the case of many vehicles forming a queue, i.e., vehicles traveling at a predetermined speed and distance apart. While the majority of existing studies on this subject have focused on the influence of the longitudinal vehicle spacing, vehicle speed, and the number of vehicles on aerodynamic drag and fuel economy, this study considers the lateral offset distance of the vehicle queue. The group fuel consumption… More >

  • Open Access


    CFD-Based Optimization of a Shell-and-Tube Heat Exchanger

    Juanjuan Wang*, Jiangping Nan, Yanan Wang

    FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.11, pp. 2761-2775, 2023, DOI:10.32604/fdmp.2023.021175

    Abstract The main objective of this study is the technical optimization of a Shell-and-Tube Heat Exchanger (STHE). In order to do so, a simulation model is introduced that takes into account the related gas-phase circulation. Then, simulation verification experiments are designed in order to validate the model. The results show that the temperature field undergoes strong variations in time when an inlet wind speed of 6 m/s is considered, while the heat transfer error reaches a minimum of 5.1%. For an inlet velocity of 9 m/s, the heat transfer drops to the lowest point, while the heat transfer error reaches a… More >

  • Open Access


    Understanding of Airfoil Characteristics at High Mach-Low Reynolds Numbers

    Zhaolin Chen1,*, Xiaohui Wei1, Tianhang Xiao1, Ning Qin2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.2, pp. 1-1, 2023, DOI:10.32604/icces.2023.09976

    Abstract A computational study has been conducted on various airfoils to simulate flows at low Reynolds numbers 17,000 and 21,000 with Mach number changes from 0.25 to 0.85 to provide understanding and guidance for Mars rotory wing designs. The computational fluid dynamics tool used in this study is a Reynolds-averaged Navier–Stokes solver with a transition model (k-ω SST γ-Reθ). The airfoils investigated in this study include NACA airfoils (4, 5, and 6% camber), UltraThin airfoils, and thin cambered plates (3% camber, but various maximum camber locations). Airfoils were examined for lift and drag performance as well as surface pressure and flow… More >

  • Open Access


    Passive Control of Base Pressure in a Converging-Diverging Nozzle with Area Ratio 2.56 at Mach 1.8

    Nur Husnina Muhamad Zuraidi1, Sher Afghan Khan1,*, Abdul Aabid2,*, Muneer Baig2, Istiyaq Mudassir Shaiq3

    FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.3, pp. 807-829, 2023, DOI:10.32604/fdmp.2023.023246

    Abstract In this study, a duct is considered and special attention is paid to a passive method for the control of the base pressure relying on the use of a cavity with a variable aspect ratio. The Mach number considered is 1.8, and the area ratio of the duct is 2.56. In particular, two cavities are examined, their sizes being 3:3 and 6:3. The used L/D spans the interval 1–10 while the NPRs (nozzle pressure ratio) range from 2 to 9. The results show that the control becomes effective once the nozzles are correctly expanded or under-expanded. The pressure contours at… More >

  • Open Access


    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 is to estimate the pitch… More >

  • Open Access


    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 the moving wing. The analysis… More >

  • Open Access


    Numerical Study on Aerodynamic Performance of High-Speed Pantograph with Double Strips

    Zhiyuan Dai1, Tian Li1, *, 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 >

  • Open Access


    Effect of RANS Model on the Aerodynamic Characteristics of a Train in Crosswinds Using DDES

    Tian Li1, *, Zhiyuan Dai1, Weihua Zhang1

    CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.2, pp. 555-570, 2020, DOI:10.32604/cmes.2020.08101

    Abstract Detached eddy simulation has been widely applied to simulate the flow around trains in recent years. The Reynolds-averaged Navier-Stokes (RANS) model for delayed detached eddy simulation (DDES) is an essential user input. The effect of the RANS model for DDES on the aerodynamic characteristics of a train in crosswinds is investigated in this study. Three different DDES models are used, based on the Spalart-Allmaras model (SA), the realizable k-ε model (RKE), and the shear stress transport k-ω model (SST). Results show that all DDES models can give relatively accurate predictions of pressure coefficient on almost all surfaces. There are only… More >

  • Open Access


    Effect of cross flow on aerodynamics of a commercial airplane

    Yangkyun kim1, Sungcho Kim2, Jongwook Choi2, Jeong Soo Kim2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.4, pp. 123-124, 2009, DOI:10.3970/icces.2009.011.123

    Abstract This paper analyzes computationally the flow field for the full geometry model of a commercial passenger airplane, Boeing747-400. The geometric dimension of an airplane was acquired by means of the reverse engineering technique adopting the photo scanning measurement. The steady three-dimensional viscous compressible flow field was calculated when the airplane cruises under side flow. The basic computational conditions were considered as the same to those of Boeing 747-400's cruising state, i.e., the atmospheric condition at 13 km above the sea level and Mach number of 0.85. The boundary conditions are the same that the freestream with side flow approaches to… More >

  • Open Access


    A Parameter Free Cost Function for Multi-Point Low Speed Airfoil Design

    G. Veble1,2,3

    CMES-Computer Modeling in Engineering & Sciences, Vol.36, No.3, pp. 243-260, 2008, DOI:10.3970/cmes.2008.036.243

    Abstract A simple cost function is proposed that depends on the inviscid pressure distribution around an airfoil and that, when minimized, results in airfoils that promote laminar flow. Additional constraints specify the design point of the airfoil. The method allows for straightforward inclusion of multiple design points. The resulting airfoils are quantitatively similar to those already successfully used in practice. More >

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