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  • Numerical Analysis of an Insect Wing in Gliding Flight: Effect of Corrugation on Suction Side
  • Abstract We have conducted a numerical study to investigate the relationship between the aerodynamic performance of an insect wing section and the effect of corrugation in gliding flight. In particular, an Airfoil-CR, corresponding to Kesel’s Profile 2 (Kesel, Journal of Experimental Biology, vol. 203, 2000), has been used. This profile represents exactly the cross section of the so-called “Aeshna cyanea”. A smoothed variant of this profile (referred to in the present study as Airfoil-SM) has also been considered. Introducing five different variants of the Airfoil-CR corresponding to different levels of corrugation, namely M1, M2, M3, M4 and M5, an unsteady fluid…
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  • On the Control of the Master Cylinder Hydraulic Pressure for Electro-Hydraulic Brake (EHB) Systems with the Sliding Mode Design Methodology
  • Abstract The brake-by-wire system requirement is promoted owing to the development of green energy vehicle, and the brake pressure control method is needed. A control method for the master cylinder hydraulic pressure based on the sliding mode control approach is proposed to provide the Electro-Hydraulic Brake system (EHB) of electric vehicles with superior system performances. An assessment is carried out about the complex nonlinear characteristics and sensitivity to the external environment of these systems, which include illustrating the working principle of the EHB system, establishing the dynamic models of the key components of the EHB system. The sliding mode control method…
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  • Recent Developments About IPMCs (Ionic Polymer-Metal) Composites: A Review of Performances for Different Conditions
  • Abstract It is of great significance for the production of micro robots and new sensors to develop actuators with “muscle” properties. As a kind of electroactive polymers (EAPs), IPMC (ionic polymer-metal composite) can exhibit significant deformation for very low electrical excitation. These composites, known as the “artificial muscle”, can be regarded as intelligent bionic materials. With regard to the mechanism of deformation of IPMC, a large number of experimental studies have proved that the variety of electrodes and water contents relating to IPMC have great influence on its electro-mechanical and mechanical properties. Recent research results about IPMC were summarized here to…
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  • Numerical Study of Natural Convection in Square Tilted Solar Cavity Considering Extended Domain
  • Abstract This work presents a numerical investigation on heat transfer and fluid-dynamic aspects for a solar open cavities in an extended fluid flow domain. The vertical wall inside the open cavities facing the aperture is assumed to be isothermal while the other walls are kept insulated. Heat transfer steady laminar natural convection is studied by solving the non-dimensional governing equations of mass, momentum and energy in the framework of a finite volume method. The analysis are carried out under Rayleigh number range of 9.41×105 to 3.76×106, inclination 0° to 90° and opening ratio 0.25, 0.5 and 1. The model results for…
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  • Numerical Investigation of Combined Surface Radiation and Free Convection in a Square Enclosure with an Inside Finned Heater
  • Abstract The study goes further to investigate a two-dimensional numerical model coupling free convection and surface radiation in an air-filled cavity containing a heated thin finned plate. The square enclosure is subjected to isothermal and insulated boundary conditions while the heating element location is varied from the horizontal position (HPFU, HPFD) to the vertical position (VPFL). The dimensionless governing equations under Boussinesq approximations are coupled with a radiative model through the boundaries conditions and solved by the Finite Volume Method. The effects of the pertinent parameters, namely, Rayleigh number (103≤Ra≤106), fin length (0.125≤La≤0.875), fin position (0.25≤Ha≤0.75) and wall emissivity (0≤ε≤1) are…
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  • Numerical Solutions of Unsteady MHD Flow Heat Transfer Over a Stretching Surface with Suction or Injection
  • Abstract The objective of the present problem is to investigate a two-dimensional unsteady flow of a viscous incompressible electrically conducting fluid over a stretching surface taking into account a transverse magnetic field of constant strength. Applying the similarity transformation, the governing boundary layer equations of the problem converted into nonlinear ordinary differential equations and then solved numerically using fourth order Runge-Kutta method with shooting technique. The effects of various parameters on the velocity and temperature fields as well as the skin-friction coefficient and Nusselt number are presented graphically and discussed qualitatively.
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  • Experimental and Theoretical Analysis of a Novel Cascade Solar Desalination Still
  • Abstract Ocean water is characterized by very high salinity, which generally makes it unsuitable for human or animal's needs. The production of potable water from the ocean, therefore, requires a desalination process, which is often regarded as the crucial limitation to overcome towards widespread use of ocean water as the primary source of water for human consumption. In this study, we analyze both experimentally and theoretically the thermal performances and productivity of a solar still based on a novel form of absorber plate. The related system of energy equations consists of five heat exchange relationships in the form of first differential…
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  • Effect of Geometrical Parameters on Vortex Fluidic Oscillators Operating with Gases and Liquids
  • Abstract The fluidic oscillator is an interesting device developed for passive flow measurement. These microsystems can produce a high oscillating jet frequency with high flow velocity. The main advantages of fluidic oscillators are that no moving parts is included in the device. Commercial CFD code FLUENT was used to perform analysis of flows in fluidic oscillator. Numerical simulations were carried out for different flow conditions, where water and air were used as working fluids. The oscillation frequencies were identified by the discrete fast Fourier transform method (FFT). Furthermore a low-pressure vortex of fluid flow in the oscillating chamber was observed. The…
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  • Three-Dimensional Numerical Investigation of Convective Thermal Instabilities in the Sapphire Melt for Czochralski Growth Process
  • Abstract In this work we have performed a three-dimensional numerical investigation in order to find the optimal conditions for growing efficiently high quality sapphire crystals with good thermal properties. We have studied thermal instabilities near the melt-crystal interface and the convective heat transfer under the Czochralski (Cz) process. We performed 3-D CFD simulation in cylindrical coordinates and used the Fast Fourier Transform method to analyze the temperature fluctuations. We present a detailed investigation on the effects of the crystal rotation speed and the temperature distribution on thermal instabilities of sapphire melt under forced convection. Where the melt forced convection, the radiative…
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  • Combined MHD and Pulsatile Flow on Porous Medium
  • Abstract This work investigates the dynamic behavior of a pulsatile flow electrically conducting through porous medium in a cylindrical conduit under the influence of a magnetic field. The imposed magnetic field is assumed to be uniform and constant. An exact solution of the equations governing magneto hydro-dynamics (MHD) flow in a conduit has been obtained in the form of Bessel functions. The analytical study has been used to establish an expression between the Hartmann number, Darcy number and the stress coefficient. The numerical method is based on an implicit finite difference time marching scheme using the Thomas algorithm and Gauss Seidel…
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