Home / Advanced Search

  • Title/Keywords

  • Author/Affliations

  • Journal

  • Article Type

  • Start Year

  • End Year

Update SearchingClear
  • Articles
  • Online
Search Results (30)
  • Open Access

    ARTICLE

    Determination of the Circulation for a Large-Scale Wind Turbine Blade Using Computational Fluid Dynamics

    Hao Cheng, Guangsheng Du*, Meng Zhang, Kun Wang, Wenbin Bai

    FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 685-698, 2020, DOI:10.32604/fdmp.2020.09673 - 11 August 2020

    Abstract The determination of the circulation for wind turbine blades is an important problem in engineering. In the present study, we develop a specific approach to evaluate the integral that represents mathematically the circulation. First the potentialities of the method are assessed using a two-dimensional NACA64_A17 airfoil as a testbed and evaluating the influence of different integration paths and angles of attack on the circulation value. Then the method is applied to blades with different relative heights in order to provide useful reference data to be used for the optimization and reverse design of wind turbine More >

  • Open Access

    ARTICLE

    Impact Dynamics of a Dragonfly Wing

    Lihua Wang1, *, Wenjing Ye1, Yueting Zhou1

    CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.3, pp. 889-906, 2020, DOI:10.32604/cmes.2020.09013 - 01 March 2020

    Abstract The lift force was reported not to be high enough to support the dragonfly’s weight during flight in some conventional investigations, and higher lift force is required for its takeoff. In this study, by employing a thin plate model, impact effect is investigated for the wing deformation in dragonfly flapping during takeoff. The static displacement is formulated to compare with the dynamical displacement caused by impact. The governing equation of motion for the impact dynamics of a dragonfly wing is derived based on Newton’s second law. Separation of variables technique and assumed modes method are More >

  • Open Access

    ARTICLE

    Finite Element Investigation of Flow Field Below Asymmetric Drill Bits for Reverse Circulation in Drilling Tight Oil and Gas Reservoirs

    Yi Luo1,*, Erxiu Shi2, Yin Feng2, Boyun Guo2, Liehui Zhang1

    CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.1, pp. 105-122, 2019, DOI:10.32604/cmes.2019.06500

    Abstract Development of unconventional tight oil and gas reservoirs such as shale pays presents a huge challenge to the petroleum industry due to the naturally low permeability of shale formations and thus low productivity of oil and gas wells. Shale formations are also vulnerable to the contamination of the water in the drilling and completion fluids, which further reduces reservoir permeability. Although gas-drilling (drilling with gas) has been used to address the issue, several problems such as formation water influx, wellbore collapse, excessive gas volume requirement and hole cleaning in horizontal drilling, still hinder its application.… More >

  • Open Access

    ARTICLE

    Numerical Simulation of An Experienced Farmer Lifting Tubers of Cassava for Designing A Bionic Harvester

    Wang Yang1,2, Juanjuan Li1, Jian Yang1,3, Lin Wei4

    CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.6, pp. 471-491, 2015, DOI:10.3970/cmes.2015.104.471

    Abstract Harvesting is the most difficult and costly operation in cassava production. Currently, most cassava harvest still depends on manual tools. Effective mechanized harvesters are necessary to improve harvesting quality and reduce production cost. Therefore, it is very important to figure out key information for designing an effective tuber lifting system used in bionic “dig-pull” harvesters. A numerical simulation model of human-stem-tuber-soil system was developed to carry out numerical simulation of manually pulling tuber. Coupling algorithm of Lagrange and smoothed particle hydrodynamics (SPH) was used in the model. Lifting mechanism of experienced farmer was studied at… More >

  • Open Access

    ARTICLE

    Construction of Operator-Orthogonal Wavelet-Based Elements for Adaptive Analysis of Thin Plate Bending Problems

    Y.M. Wang1,2, Q. Wu1

    CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.1, pp. 17-45, 2013, DOI:10.3970/cmes.2013.093.017

    Abstract A new kind of operator-orthogonal wavelet-based element is constructed based on the lifting scheme for adaptive analysis of thin plate bending problems. The operators of rectangular and skew thin plate bending problems and the sufficient condition for the operator-orthogonality of multilevel stiffness matrix are derived in the multiresolution finite element space. A new type of operator-orthogonal wavelets for thin plate bending problems is custom designed with high vanishing moments to be orthogonal with the scaling functions with respect to the operators of the problems, which ensures the independent solution of the problems in each scale. More >

  • Open Access

    ARTICLE

    Distribution of the Sizes of Rock Cuttings in Gas Drilling At Various Depths

    Jun Li1, Shunji Yang1, Boyun Guo1,2, Yin Feng2, Gonghui Liu1,3

    CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 79-96, 2012, DOI:10.3970/cmes.2012.089.079

    Abstract In the process of gas drilling, the mechanism of transport of the cuttings up the annulus is significant, because it controls the minimum amount of volume of the required gas, the cost of cleaning the borehole, the stability of the borewell and the drill pipe erosion, etc. However, current studies in this area are only limited to theoretical discussions. The reason why drill cuttings are of very fine sizes , in air drilling, is believed to be due to the repeated crushing action of drill bit at the bottom of the hole, and the collision… More >

  • Open Access

    ARTICLE

    The Design of Multi-Element Airfoils Through Multi-Objective Optimization Techniques

    G. Trapani1, T. Kipouros1, A. M. Savill1

    CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.2, pp. 107-140, 2012, DOI:10.3970/cmes.2012.088.107

    Abstract This paper presents the development and the application of a multi-objective optimization framework for the design of two-dimensional multi-element high-lift airfoils. An innovative and efficient optimization algorithm, namely Multi-Objective Tabu Search (MOTS), has been selected as core of the framework. The flow-field around the multi-element configuration is simulated using the commercial computational fluid dynamics (cfd) suite Ansys cfx. Elements shape and deployment settings have been considered as design variables in the optimization of the Garteur A310 airfoil, as presented here. A validation and verification process of the cfd simulation for the Garteur airfoil is performed… More >

  • Open Access

    ARTICLE

    POOL BOILING CHF FOR PENTANE, HEXANE, METHANOL, FC-72, FC-87, AND R113 ON A SMOOTH HORIZONTAL SURFACE

    Cheng-Kang Guan, James F. Klausner*, Renwei Mei

    Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-6, 2011, DOI:10.5098/hmt.v2.4.3002

    Abstract Pool boiling critical heat flux (CHF) has been measured for pentane, hexane, methanol, FC-72, FC-87, and R113 on a 25.4 mm diameter smooth brass horizontal surface at five different reduced pressures ranging from 0.01to 0.24. The CHF data are compared with various established CHF models as well as the new mechanistic CHF lift-off model recently proposed by the authors. The dependence of CHF on pressure is examined, and it is found that the lift-off model gives a reasonably good prediction of changes in CHF with step changes in the reduced pressure. The R113 and FC-72 More >

  • Open Access

    ABSTRACT

    Dynamic simulation of the Power Shift Drive (PSD)-Axle in the Forklift

    Ji Won Yoon1, Tae Won Park2, Kab Jin Jun3, Soo Ho Lee3, Sung Pil Jung3

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.3, pp. 73-74, 2009, DOI:10.3970/icces.2009.011.073

    Abstract Industrial vehicles like forklifts are used in many areas, such as the heavy industries, shipbuilding, and manufacturing industries. Recently, the rise in the oil prices and stricter environmental regulations have created the need for new technologies for industrial vehicles. Presently, the performance of the power train has reached its limit and cannot be further improved without increasing cost, weight and volume. Therefore, a system based on a new paradigm is needed. To achieve this goal, the structure of the power transfer system needs to be revolutionized. First, weight and size need to be reduced. In… More >

  • Open Access

    ARTICLE

    Hydraulic lift in and between vegetation patches in arid Argentina

    Bonvissuto GL1, CA Busso2,*

    Phyton-International Journal of Experimental Botany, Vol.75, pp. 55-70, 2006, DOI:10.32604/phyton.2006.75.055

    Abstract This study was conducted in the Monte Austral Neuquino (MAN), Provincia de Neuquén, Argentina (39°20’ S; 69°19’ W). Vegetation is distributed at the site as vegetation patches. There are two contrasting sites on the soil of these patches: location 1, under the canopy of major perennial grasses and shrubs, and location 2, which includes the vegetation uncovered interspaces between the patches. The hypothesis of this work was that hydraulic lift is greater under than between the vegetation patches. Thermocouple psychrometers were placed under the shrubs and in the interspaces in each of two vegetation patches,… More >

Displaying 21-30 on page 3 of 30. Per Page