• Title/Summary/Keyword: Wave parameters

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Wave propagation analysis of the ball in the handball's game

  • Yongyong Wang;Qixia Jia;Tingting Deng;Mostafa Habibi;Sanaa Al-Kikani;H. Elhosiny Ali
    • Structural Engineering and Mechanics
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    • v.85 no.6
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    • pp.729-742
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    • 2023
  • It is a recent attraction to the mechanical scientists to investigate state of wave propagation, buckling and vibration in the sport balls to observe the importance of different parameters on the performance of the players and the quality of game. Therefore, in the present study, we aim to investigate the wave propagation in handball game ball in term of mass of the ball and geometrical parameters wit incorporation of the viscoelastic effects of the ball material into account. In this regard, the ball is modeled using thick shell structure and classical elasticity models is utilized to obtain the equation of motion via Hamilton's principle. The displacement field of the ball model is obtained using first order shear deformation theory. The resultant equations are solved with the aid of generalized differential quadrature method. The results show that mass of the ball and viscoelastic coefficient have considerable influence on the state of wave propagation in the ball shell structure.

Wave propagation of FG-CNTRC plates in thermal environment using the high-order shear deformation plate theory

  • Hao-Xuan Ding;Hai-Bo Liu;Gui-Lin She;Fei Wu
    • Computers and Concrete
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    • v.32 no.2
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    • pp.207-215
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    • 2023
  • This paper investigates wave propagation in functionally graded carbon nano-reinforced composite (FG-CNTRC) plates under the influence of temperature based on Reddy' plate model. The material properties of Carbon Nanotubes (CNTs) are size-dependent, and the volume fraction of CNTs varies only along the thickness direction of the plate for different CNTs reinforcement modes. In addition, the material properties of CNTs can vary for different temperature parameters. By solving the eigenvalue problem, analytical dispersion relations can be derived for CNTRC plates. The partial differential equations for the system are derived from Lagrange's principle and higher order shear deformation theory is used to obtain the wave equations for the CNTRC plate. Numerical analyses show that the wave propagation properties in the CNTRC plate are related to the volume fraction parameters of the CNTRC plate and the distribution pattern of the CNTs in the polymer matrix. The effects of different volume fractions of CNTs and the distribution pattern of carbon nanotubes along the cross section (UD-O-X plate) are discussed in detail.

Wave propagation of bi-directional porous FG beams using Touratier's higher-order shear deformation beam theory

  • Slimane Debbaghi;Mouloud Dahmane;Mourad Benadouda;Hassen Ait Atmane;Nourddine Bendenia;Lazreg Hadji
    • Coupled systems mechanics
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    • v.13 no.1
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    • pp.43-60
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    • 2024
  • This work presents an analytical approach to investigate wave propagation in bi-directional functionally graded cantilever porous beam. The formulations are based on Touratier's higher-order shear deformation beam theory. The physical properties of the porous functionally graded material beam are graded through the width and thickness using a power law distribution. Two porosities models approximating the even and uneven porosity distributions are considered. The governing equations of the wave propagation in the porous functionally graded beam are derived by employing the Hamilton's principle. Closed-form solutions for various parameters and porosity types are obtained, and the numerical results are compared with those available in the literature.The numerical results show the power law index, number of wave, geometrical parameters and porosity distribution models affect the dynamic of the FG beam significantly.

A Parametric Study on the Characteristics of the Oil-Lubricated Wave Journal Bearing (오일윤활 웨이브 저어널 베어링의 특성해석)

  • 서현승;임윤철
    • Tribology and Lubricants
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    • v.14 no.4
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    • pp.100-107
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    • 1998
  • A new bearing concept, the wave journal bearing, has been developed to improve the static and dynamic performance of a hydrodynamic journal bearing. This concept features a wave in bearing surface. Not only straight but also twisted wave journal bearing are investigated numerically. The performances of straight and twisted bearings are compared to a plain journal bearing over a wide range of eccentricity. The bearing load and stability characteristics are dependent on the geometric parameters such as the number of waves, the amplitude and the start point of the wave relative to the applied load direction. The wave journal bearing, especially for the twisted one, offers better stability than the plain journal bearing under all eccentricity and load orientation.

An Analysis of Wave Journal Bearing (웨이브 저어널 베어링의 특성해석)

  • 서현승;임윤철
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.04a
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    • pp.190-197
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    • 1998
  • A new bearing concept, the wave journal bearing, has been developed to improve the steady and dynamic performance of a hydrodynamic journal bearing. This concept features a wave in inner bearing surface. Not only straight but also twisted wave journal bearing are investigated numerically. The performances of straight and twisted bearings are compared to a plain journal bearing over a relatively wide range of eccentricity. The bearing load and stability characteristics are dependent on the geometric parameters such as the number of waves, the amplitude and the starting point of the wave relative to the applied load. The wave journal bearing, especially for the twisted one, offers better stability than the plain journal bearing under all eccentricity and all wave to load orientation.

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Numerical Analysis for Wave Propagation and Sediment Transport with Coastal Vegetation (연안식생에 의한 표사이동 특성에 관한 수치해석)

  • Lee, Seong-Dae
    • Journal of Ocean Engineering and Technology
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    • v.21 no.5
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    • pp.18-24
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    • 2007
  • The environmental value of coastal vegetation has been widely recognized. Coastal vegetation such as reed forests and seaweed performs several useful functions, including maintaining water quality, supporting fish (and, thus, fisheries), protecting beaches and land from wave attack, stabilizing sea beds and providing scenic value. However, studies on the physical and numerical process of wave propagation, sediment transport and bathymetric change are few and far between compared to those on the hydrodynamic roles of coastal vegetation. In general, vegetation flourishing along the coastal areas attenuates the incident waves through momentum exchange between stagnated water mass in the vegetated area and rapid mass in the un-vegetated area. This study develops a numerical model for describing the wave attenuation and sediment transport in a wave channel in a vegetation area. By comparing these results, the effects of vegetation properties, wave properties and model parameters are clarified.

Influence of a Structure by the Submerged Breakwater and the Porous Wave Absorber (수중방파제와 다공성 소파장치가 구조물에 미치는 영향)

  • Park, Jin-Ho;Jung, Tae-Hwa;Cho, Yong-Sik
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.225-228
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    • 2008
  • There are many studies about submerged structures or porous wave absorbers to decrease damage of coast and structures. Submerged structures and porous wave absorber are decreasing energy of incoming wave by reflecting or dissipation with changing depth or with porous rubble mound. This study addresses the reflection and transmission of long wave from a trapezoidal breakwater and a vertical porous wave absorber at the same time. A systematic shape transfer is derived to determine wave reflection and transmission. And periodic solutions are matched at the slope and the front face of the absorber by assuming continuity of pressure and mass. The transmission coefficient is determined as a function of parameters describing the incoming waves, transmitting waves through the trapezoidal breakwater and the absorber characteristics.

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A new size-dependent shear deformation theory for wave propagation analysis of triclinic nanobeams

  • Karami, Behrouz;Janghorban, Maziar
    • Steel and Composite Structures
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    • v.32 no.2
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    • pp.213-223
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    • 2019
  • For the first time, longitudinal and transverse wave propagation of triclinic nanobeam is investigated via a size-dependent shear deformation theory including stretching effect. Furthermore, the influence of initial stress is studied. To consider the size-dependent effects, the nonlocal strain gradient theory is used in which two small scale parameters predict the behavior of wave propagation more accurately. The Hamiltonian principle is adopted to obtain the governing equations of wave motion, then an analytic technique is applied to solve the problem. It is demonstrated that the wave characteristics of the nanobeam rely on the wave number, nonlocal parameter, strain gradient parameter, initial stress, and elastic foundation. From this paper, it is concluded that the results of wave dispersion in isotropic and anisotropic nanobeams are almost the same in the presented case study. So, in this case, triclinic nanobeam can be approximated with isotropic model.

Numerical study on supercavitating flow in free stream with regular waves

  • Li, Da;Lyu, Xujian
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.12 no.1
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    • pp.799-809
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    • 2020
  • In this study, the supercavitating flow of a high-velocity moving body near air-water surface is calculated and analyzed based on a commercial CFD software ANSYS Fluent. The effect of regular wave parameters including both wave height and wavelength on the cavitating flow and force characteristics of a body at different velocities is investigated. It is found that the cavity shape, lift coefficient and drag coefficient of the body vary periodically with wave fluctuation, and the variation period is basically consistent with wave period. When the wavelength is much greater than the cavity length, the effect of wave on supercavitation is the alternating effect of axial compression and radial compression. However, when the wavelength varies around the cavity length, the cavity often crosses two adjacent troughs and is compressed periodically by the two wave troughs. With the variation of wavelength, the average area of cavity shows a different trend with the change of wave height.

A Parametric Study of the Wave-Generation Performance of a Piston-Type Wave Maker (피스톤 타입 조파기의 형상 매개변수에 대한 조파성능 연구)

  • Kwon, Do-Soo;Kim, Sung-Jae;Koo, Weoncheol
    • Journal of Ocean Engineering and Technology
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    • v.33 no.6
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    • pp.504-509
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    • 2019
  • The wave-generation performance of a piston-type wave maker was analyzed using the numerical wave tank technique, and the numerical results were compared with theoretical solutions. A two-dimensional frequency domain analysis was conducted based on the Rankine panel method. Various parameters were used to examine the wave-generation performance, such as the width and gap of the wave board. The effects of the thickness of the wave board and of the gap from the bottom of the tank were evaluated. The difference in the amplitude of the generated wave between the analytical solution and the numerical result was examined, and its causes were addressed due to the gap flow between the bottom of the tank and the wave board. This parametric analysis can be utilized to design an optimum wave make parametric analysis to design an optimum wave maker that can generate waves with amplitudes that can be predicted accurately.