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  • Open Access

    ARTICLE

    Development of a Numerical Toolbox for the Computer Aided Design of Composite Over-Wrapped Pressure Vessels

    Eugenio Brusa1, Matteo Nobile2

    CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.2, pp. 155-190, 2009, DOI:10.3970/cmes.2009.048.155

    Abstract Lightness of high pressure vessels is currently assured by composite materials. Construction of over-wrapped composite pressure vessels with inner metallic liner is for instance compatible with standards requirements of the hydrogen technology of energy storage. Therefore a typical layout manufactured by some industries consists of a cylindrical vessel with covering of carbon-epoxy laminates and metallic impermeable liner. To allow the filament winding of the composite fibres are used hoop and helical layers, respectively. A single nozzle is usually built. It requires that the vessel material is reinforced. This need imposes to have a variable thickness in the composite layer. In… More >

  • Open Access

    ARTICLE

    Stabilized Meshless Local Petrov-Galerkin (MLPG) Method for Incompressible Viscous Fluid Flows

    M. Haji Mohammadi1

    CMES-Computer Modeling in Engineering & Sciences, Vol.29, No.2, pp. 75-94, 2008, DOI:10.3970/cmes.2008.029.075

    Abstract In this paper, the truly Meshless Local Petrov-Galerkin (MLPG) method is extended for computation of steady incompressible flows, governed by the Navier--Stokes equations (NSE), in vorticity-stream function formulation. The present method is a truly meshless method based on only a number of randomly located nodes. The formulation is based on two equations including stream function Poisson equation and vorticity advection-dispersion-reaction equation (ADRE). The meshless method is based on a local weighted residual method with the Heaviside step function and quartic spline as the test functions respectively over a local subdomain. Radial basis functions (RBF) interpolation is employed in shape function… More >

  • Open Access

    ARTICLE

    Modeling and Bending Vibration of the Blade of a Horizontal-Axis Wind Power Turbine

    Shueei-Muh Lin1, Sen-Yung Lee2, Yu-Sheng Lin3

    CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.3, pp. 175-186, 2008, DOI:10.3970/cmes.2008.023.175

    Abstract The blade of a horizontal-axis wind power turbine is modeled as a rotating beam with pre-cone angles and setting angles. Based on the Bernoulli-Euler beam theory, without considering the axial extension deformation and the Coriolis forces effect, the governing differential equations for the bending vibration of the beam are derived. It is pointed out that if the geometric and the material properties of the beam are in polynomial forms, then the exact solution for the system can be obtained. Based on the frequency relations as revealed, without tedious numerical analysis, one can reach many general qualitative conclusions between the natural… More >

  • Open Access

    ARTICLE

    Wind Set-down Relaxation

    Baran Aydın1,2, Utku Kânoğlu3

    CMES-Computer Modeling in Engineering & Sciences, Vol.21, No.2, pp. 149-156, 2007, DOI:10.3970/cmes.2007.021.149

    Abstract We developed analytical solutions to the wind set-down and the wind set-down relaxation problems. The response of the ocean to the wind blowing over a long-narrow and linearly sloping shallow basin is referred to as wind set-down. The shoreline exhibits oscillatory behavior when the wind calms down and the resulting problem is referred to as wind set-down relaxation. We use an existing hodograph-type transformation that was introduced to solve the nonlinear shallow-water wave equations analytically for long wave propagation and obtain an explicit-transform analytical solution for wind set-down. For the wind set-down relaxation, the nonlinear shallow-water wave equations are solved… More >

  • Open Access

    ARTICLE

    The Meshless Local Petrov-Galerkin (MLPG) Method for Solving Incompressible Navier-Stokes Equations

    H. Lin, S.N. Atluri1

    CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.2, pp. 117-142, 2001, DOI:10.3970/cmes.2001.002.117

    Abstract The truly Meshless Local Petrov-Galerkin (MLPG) method is extended to solve the incompressible Navier-Stokes equations. The local weak form is modified in a very careful way so as to ovecome the so-called Babus~ka-Brezzi conditions. In addition, The upwinding scheme as developed in Lin and Atluri (2000a) and Lin and Atluri (2000b) is used to stabilize the convection operator in the streamline direction. Numerical results for benchmark problems show that the MLPG method is very promising to solve the convection dominated fluid mechanics problems. More >

  • Open Access

    ARTICLE

    Meshless Local Petrov-Galerkin (MLPG) Method for Convection-Diffusion Problems

    H. Lin, S.N. Atluri1

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.2, pp. 45-60, 2000, DOI:10.3970/cmes.2000.001.205

    Abstract Due to the very general nature of the Meshless Local Petrov-Galerkin (MLPG) method, it is very easy and natural to introduce the upwinding concept (even in multi-dimensional cases) in the MLPG method, in order to deal with convection-dominated flows. In this paper, several upwinding schemes are proposed, and applied to solve steady convection-diffusion problems, in one and two dimensions. Even for very high Peclet number flows, the MLPG method, with upwinding, gives very good results. It shows that the MLPG method is very promising to solve the convection-dominated flow problems, and fluid mechanics problems. More >

  • Open Access

    ARTICLE

    A Practical Engineering Approach to the Design and Manufacturing of a mini kW BladeWind Turbine: Definition, optimization and CFD Analysis

    G. Frulla1, P. Gili1, M. Visone2, V. D’Oriano2,3, M. Lappa4

    FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.3, pp. 257-277, 2015, DOI:10.3970/fdmp.2015.011.257

    Abstract A practical engineering approach to the design of a 60 kW wind generator with improved performances is presented. The proposed approach relies on the use of a specific, "ad hoc'' developed software, OPTIWR (Optimization Software), expressly conceived to define an "optimum'' rotor configuration in the framework of the blade-element-momentum theory. Starting from an initial input geometric configuration (corresponding to an already existing 50 kW turbine) and for given values of the wind velocity Vwind and of the advance ratio X = Vwind/ΩR (where Ω is the blade rotational speed and R is the propeller radius), this software is used to… More >

  • Open Access

    ARTICLE

    Contribution to Improving the Performance of a Wind Turbine Using Natural Convection

    M. Kriraa1,2, M.EL Alami1, M. Abouricha1

    FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.4, pp. 443-464, 2014, DOI:10.3970/fdmp.2014.010.443

    Abstract Natural Convection in a vertical channel with internal objects is encountered in several technological applications, among them particular interest of heat dissipation from electronic circuits, refrigerators, heat exchangers, nuclear reactors fuel elements, dry cooling towers, home ventilation, etc. This numerical study deals with the study of natural convection in a vertical convergent channel with a circular block. The considered parameters are 104Ra ≤ 106, Prandtl number Pr = 0.71, channel height 10 ≤ A ≤ 30, inclination angle of the channel φ = 0,2.86°,5.74°. The size block conductivity and the block radius are assumed to be constant Λ… More >

  • Open Access

    ARTICLE

    Improving the Efficiency of Wind Power System by Using Natural Convection Flows

    M. Kriaa1, M. El Alami1,2, M. Najam1, E. Semma3

    FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.2, pp. 125-140, 2011, DOI:10.3970/fdmp.2011.007.125

    Abstract In this paper a numerical study of natural convection in a two dimensional convergent channel, with or without rectangular block, is carried out. The block is placed at the channel outlet and its thermal conductivity is set equal to that of air. One of channel planes is heated at constant temperature TH. The other one is maintained cold at TC < TH. The governing equations are solved using a finite volume method and the SIMLEC algorithm for the velocity-pressure coupling is used. Special emphasis is given to detail the effect of the block size and Rayleigh number on the dynamics… More >

  • Open Access

    ARTICLE

    An Experimental Study Of An Electroaerodynamic Actuator

    R. Mestiri1, R.Hadaji1, S. Ben Nasrallah1

    FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.4, pp. 409-418, 2010, DOI:10.3970/fdmp.2010.006.409

    Abstract The electroaerodynamic actuator or plasma actuator uses the characteristics of the non-thermal surface plasmas. These plasmas are created in atmospheric pressure by a DC electrical corona discharge at the surface of a dielectric material. The two electrodes are two conductive parallel wires. The applied voltage is of several kilovolts. The corona discharge creates a tangential electric wind that can modify the boundary layer flow properties. In this paper, we present the results found for two geometric configurations: the flat plate and the cylinder. In order to study the discharge specificity, we have found the current- voltage characteristics for different inter-electrode… More >

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