• Title/Summary/Keyword: The Boussinesq equation

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Numerical Analysis of Random Waves Breaking using Boussinesq Equation (Boussinesq방정식을 이용한 불규칙파의 쇄파해석)

  • Lee, Jong-In;Kim, Young-Taek
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.1931-1934
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    • 2006
  • The accuracy impact of using high-order Boussinesq-type model as compared to the typical order model is examined in this paper. The multi-layer model developed by Lynett and Liu(2004a) is used for simulating of wave breaking over a step region. The overall comparisons between the two-layer model and the hydraulic experiments are quite good. The one-layer model overshoals the wave near the breakpoint, while the two-layer model shoals at a rate more consistent with the experimental data.

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Shoaling and Breaking Characteristics of Fully Nonlinear Boussinesq Model (완전비선형 Boussinesq 모형의 천수 및 쇄파 특성)

  • YOON JONG-TAE;PARK SEUNG-MIN
    • Journal of Ocean Engineering and Technology
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    • v.19 no.2 s.63
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    • pp.29-33
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    • 2005
  • The accuracy of predicting wave transformation in the nearshore is very important to wave hydrodynamics, sediment transport, and design of coastal structures. Numerical experiments are conducted to identify the shoaling and breaking characteristics of a fully nonlinear Boussinesq equation-based model. Simulated shoaling showed good agreement with the Shouto's formula, and the results of the breaking experiment agreed well with experimented data, over several beach profile.

Derivation of Nonlinear Model for Irregular Waves on Miled Slpoe (비선형 불규칙 완경사 파랑 모델의 유도)

  • 이정렬
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.6 no.3
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    • pp.281-289
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    • 1994
  • An equation set of nonlinear model for regular/irregular waves presented in this study can be applied to waves travelling from deep water to shallow water, which is different from the Boussinesq equations. The presented equations completely satisfy the linear dispersion relationship and when expanded, they are proven to be consistent with the Boussinesq equation of several types. In addition, the position of averaged velocity below the still water level is estimated based on the linear wave theory.

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Low-pass Filters for Removing Numerical Noises of Boussinesq Equation Model (Boussinesq 방정식 모델의 수치잡음 제거를 위한 저파수 통과 필터에 대한 고찰)

  • Chun, In-Sik;Sim, Jae-Seol
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.5
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    • pp.418-428
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    • 2007
  • In the calculation of wave propagation by Boussinesq equation model, it is very common to experience numerical noises generated from nonlinear interaction and breaking wave occurrence, and the numerical solution is rapidly diverged unless the noises are properly controlled. A comparative study was here undertaken for the characteristics of three different lowpass filters (FFT filter, Gaussian filter and Shapiro filter) which are all designed to be applied to the interim results of numerical calculation. The numerical results obtained with application of respective filter techniques were compared with the results of an existing hydraulic experiment for the aspects of noise suppression, conservation of main signal and altering time. The results show that the Shapiro filter can be best applied with optimal choices of its element number, pass number and filtering tune interval. The combination of the number of filter element off, pass number of 50 or less, and application interval of 100 to 200 time steps generally showed good performance in both accuracy and efficiency of the numerical calculation.

Stem Wave Analysis of Regular Waves using a Boussinesq Equation (Boussinesq 방정식을 이용한 규칙파의 연파해석)

  • Lee, Jong-In;Kim, Young-Taek;Yoon, Sung-Bum
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.5
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    • pp.446-456
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    • 2007
  • Numerical analyses of stem waves, the interaction between incident and reflected waves of obliquely incident regular waves along a vertical wall in a constant water depth, are presented. For the numerical model of the analysis, the two-layer Boussinesq equations developed by Lynett and Liu(2004a,b) are employed. Numerical results are compared with both laboratory measurements and those obtained using parabolic approximation model. The overall comparisons between the results from the two numerical models and the experiments are good. However, the two-layer Boussinesq model is more accurate than the parabolic approximation model as the angle of incident waves increases. In particular, the higher harmonic generation due to the wave nonlinearity is captured only in the Boussinesq model.

Analysis of Hertzian Contact using East Fourier Transform (FFT를 이용한 Hertzian Contact 해석)

  • 구영필;조용주
    • Tribology and Lubricants
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    • v.14 no.4
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    • pp.121-127
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    • 1998
  • In this study, a numerical procedure to solve a contact problem has been developed. The procedure takes advantage of signal processing technique in frequency domain to achieve shorter computing time. Boussinesq's equation was adopted as the response function. This procedure is applicable to a non-periodic surface profile as well as a periodic one. The validity of this procedure has been established by comparing the numerical results with the exact solutions. The fastness of this procedure was shown in comparison with other algorithm.

Transformation of Long Waves with Vertical Acceleration (연식방향의 가속도를 고려한 장파의 변형해석)

  • 여운광
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.2 no.2
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    • pp.112-117
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    • 1990
  • Boussinesq-type equations should be employed in which the water surface profile is considerably steep or the bottom topography is abruptly changed. The primary reason is that the pressure deviates significantly from the hydrostatic pressure distribution due to the large curvature of the stream lines. It is shown that such a Boussinesq type equation can be also derived by making use of the concept of the averaged flow description for specifying the turbulence effects. In addition, a numerical scheme is developed to solve the equations and the effects of the Boussinesq term is briefly investigated.

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Evaluation of Fluid Forces Acting on Offshore Structures Placed in the Vicinity of Underwater Shoal (수중 천퇴 인근에 설치된 해양구조물에 작용하는 유체력 결정에 대한 고찰)

  • Chun, In-Sik;Min, In-Ki;Sim, Jae-Seol
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.2
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    • pp.136-145
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    • 2007
  • When waves propagating over an underwater shoal break at the top of the shoal, wave heights are drastically decreased in the downstream breaking zone, but a secondary current shooting downstream with strong velocity can be induced by the breaking waves themselves. In the case that an offshore structure is placed in the breaking zone, the estimation of wave farce purely based on the visible wave height may cause an under-design of the structure. Thus, for the safe design of the structure, the breaking wave induced current should be necessarily considered in the comprehensive estimation of design load. In the present study, Boussinesq equation model to calculate the wave height distribution and breaking wave induced current was set up and applied to the scheme of a hydraulic model test previously undertaken. Based on the results of the Boussinesq model, fluid forces acting on the model structure were calculated and compared with the experimental results. The importance of the breaking wave induced current was quantitatively assessed by comparing fluid forces with or without current.

Numerical Simulation of Solute Transport in Coastal Areas (해안지역에서의 용존성 물질의 이송확산 거동 수치모의)

  • Kim, Dae-Hong
    • Ecology and Resilient Infrastructure
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    • v.1 no.1
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    • pp.1-7
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    • 2014
  • In this study, a numerical simulation technique for coastal area where wave and current interactions are observed is proposed. Considering the spatial scale of coastal area and the coastal processes such as wave, current, shoaling, wave breaking, and inundation processes, boussinesq equation model is used. A depth-integrated transport model based on the consistent assumption with the boussinesq equation model is used for the prediction of solute transport. To solve the equations, finite volume method with an approximate riemann solver is used. The proposed model is applied to a coastal area and reasonable computational results are obtained.