Yongping Yu¹, Lihui Chen¹, Juanjuan Wang¹, Guoji Liu^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.2, pp. 647-670, 2020, DOI:10.32604/cmes.2020.011067

Abstract The tower line system will be in an unsafe status due to uniform or uneven fall of ice coating which is attached to the surface of tower and lines. The fall of ice could be caused by wind action or thermal force. In order to study the dynamic characteristics of the self-failure of the transmission line under the action of dynamic wind load, a finite element model of the two-span transmission tower line system was established. The birth and death element methods are used to simulate the icing and shedding of the line. Tensile failure strength is the shedding criterion… More >

Dongyue Tang¹, Ming Zhao^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.2, pp. 433-457, 2020, DOI:10.32604/cmes.2020.09268

Abstract The monopile foundation is the main form of offshore wind turbine foundation, and its surrounding scouring pit will reduce the constraints of the soil on the piles, which makes wind turbine foundation instability a key issue affecting the structural safety of offshore wind turbines. In previous studies, the rotating rotor and control system are neglected when studying the influence of scour on the offshore wind turbine structure. In this paper, the numerical model of the blade-tower-monopile integrated offshore wind turbine is established, and the influence of scour on the dynamic characteristics of wind turbine is obtained considering parameters, such as… More >

D. O. Redchyts¹, E. A. Shkvar^{2, *}, S. V. Moiseienko³

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 91-103, 2020, DOI:10.32604/fdmp.2020.07933

Abstract A method to evaluate the properties of turbulent flow in proximity to the vehicle and close to the ground surface has been elaborated. Numerical simulations have been performed on the basis of the Unsteady Reynolds-averaged Navier-Stokes equations (URANS) written with respect to an arbitrary curvilinear coordinate system. These equations have been solved using the Spalart-Allmaras differential one-parametric turbulence model. The method of artificial compressibility has been used to improve the coupling of pressure and velocity in the framework of a finite volume approach. Time-averaged distributions of pressure fields, velocity components, streamlines in the entire area and near the tractor-trailer, as… More >

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 >

Tian Li^{1, *}, 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 >

Tin-Kan Hung^1,*, Ruei-Hung Kuo², Cheng-Hsien Chiang³

Molecular & Cellular Biomechanics, Vol.17, No.1, pp. 19-24, 2020, DOI:10.32604/mcb.2019.07817

Abstract Kinematic and dynamic characteristics of pulsating flow in a model of human aortic arch are obtained by a computational analysis. Three-dimensional flow processes are summarized by pressure distributions on the symmetric plane together with velocity and pressure contours on a few cross sections for systolic acceleration and deceleration. Without considering the effects of aortic tapering and the carotid arteries, the development of tubular boundary layer with centrifugal forces and pulsation are also analyzed for flow separation and backflow during systolic deceleration. More >

Tin-Kan Hung^1,*, Ruei-Hung Kuo², Cheng-Hsien Chiang³

Molecular & Cellular Biomechanics, Vol.16, Suppl.2, pp. 90-91, 2019, DOI:10.32604/mcb.2019.07854

Abstract Pulsating flow in a human aortic arch is studied from its kinematic and dynamic characteristics of transient tubular boundary layer. The results can only be obtained by a 3D fluid dynamic (CFD) analysis for the rapidly accelerated and decelerated systolic flow. The flow is based on a prescribed inlet velocity, V_O(t), which can be expressed as the instantaneous Reynolds number, Re(t) = ρDV_O/μ in which D is the tube diameter, ρ the blood density and μ the dynamic viscosity. Computation of pressure field requires a reference pressure at the downstream end section. The pressure is based on the pulse in… More >

Biao Wang^1,*, Yongjian Yang¹, Hesong Huang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 649-678, 2019, DOI:10.31614/cmes.2019.05671

Abstract To calculate the diffusion law of chaff cloud launched by aircraft, taking rectangular chaff as an example, the diffusion model of chaff cloud is established in this paper. Firstly, the coordinate systems of chaff are defined and the motion model of chaff is established. The motion model mainly includes chaff motion equation and rotation equation, which are obtained by combining the aerodynamic moment and aerodynamic damping. Then, the influence of multi-chaff aerodynamic interference on the movement of chaff is analyzed. Finally, considering the influence of overlap area between chaffs and chaff spacing on the aerodynamic coefficients, the multi-chaff motion model… More >

J.R. Lin¹, L.M. Chu², T.L. Chou³, L.J. Liang³, P.Y. Wang³

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.2, pp. 163-177, 2014, DOI:10.3970/fdmp.2014.010.163

Abstract We investigate the influence of non-Newtonian micropolar fluids on the dynamic characteristics of wide tapered-land slider bearings. The study is carried out on the basis of the micro-continuum theory originally developed by Eringen (1966). Analytical expressions for the linear dynamic coefficients are provided and compared with earlier results in the literature. In particular, direct comparison with the Newtonian fluid-lubricated tapered-land bearings by Lin et al. (2006) indicates that the use of non-Newtonian micropolar fluids can lead to a significant increase in the values of stiffness and damping coefficients. Such improvements are found to be even more pronounced for larger values… More >