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Block Coefficient

The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform

Kazuo Suzuki – 1st expert on this subject based on the ideXlab platform

  • study on bow shape optimization of ultra large Block Coefficient ship and cfd simulations of initial and optimized hull forms
    Journal of the Society of Naval Architects of Japan, 2014
    Co-Authors: Kazuo Suzuki, Takanori Hino

    Abstract:

    The present paper describes a hull form improvement of innovative low-speed Ultra Large Block Coefficient Ship (ULBS). A hull form optimization method for reducing wave-making resistance and wave-breaking at the bow using nonlinear programming method (NLP) based on the Rankine source method is discussed. In the optimization process, wave-making resistance Coefficient,surface integrals of the square of free surface elevations and free surface disturbance function D(x,y)-values are selected as the objective functions. Bow-body shape is optimized under the prescribed design constraints based on the present method. Numerical examples are given for unconventional ULBS. The three improved hull forms for the corresponding objective functions are obtained by optimal designs which indicate that the objective functions are reduced distinctly. In order to verify the present optimization method based on the potential solver, the flow characteristics around the initial and bow optimized hull forms are analyzed by using Computational Fluid Dynamics (CFD) analysis based on the Navier-Stokes (NS) solver. Comparisons of the computed resistance Coefficients, pressure and velocity distributions of the initial and bow optimized hull forms are presented. It is confirmed that simulation results based on the viscous flow solver show reasonable agreements with the numerical results based on the Rankine source method for the bow optimized hull forms.

  • study on bow wave breaking around ultra large Block Coefficient ship
    Journal of Naval Architecture and Marine Engineering, 2013
    Co-Authors: Kazuo Suzuki, Sou Miyauchi

    Abstract:

    Due to the increase of maritime transportation volume day by day it is necessary to design a ship hull having large carrying capacity with low resistance. In case of slow moving ships, usually wave breaking occurs in front of bow. A considerable portion of resistance occurs due to the energy dissipation of such wave breaking in case of Ultra Large Block Coefficient Ship (ULBS) suggested by the authors. The key objective of this research work is to investigate the relationship between bow wave breaking and free surface disturbance function that may be used as a parameter for numerical prediction of bow wave breaking . In this regard, the experiments and numerical calculations have been carried out for six models of ULBS. From the results, it can be concluded that the wave breaking area in front of bow increases with the increase of surface integral of the square of free surface disturbance function, Froude number and Block Coefficient. DOI: http://dx.doi.org/10.3329/jname.v10i2.16104

  • proposal of ultra large Block Coefficient ship and fundamental studies on its bow wave breaking
    Journal of the Japan Society of Naval Architects and Ocean Engineers, 2013
    Co-Authors: Kazuo Suzuki, Takanori Hino

    Abstract:

    Due to the increase of maritime transportation volume day by day it is necessary to design a ship hull having large carrying capacity with low resistance. For this purpose, the authors propose innovative concepts of Ultra Large Block Coefficient Ship (ULBS). In this paper, its concepts and study plans are shown, and its bow wave breaking phenomena are investigated as one of the fundamental studies on ULBS hull form. As experimental studies, wave breaking surface areas caused by ULBS models are measured. As theoretical ones, wave making resistance Coefficients and distributions of free surface elevation are evaluated by means of Rankine source method, and distributions of free surface disturbance function D(x,y) are evaluated by means of Baba’s low speed theory. Various parameters related to the wave breaking phenomena are investigated in comparisons between experimental and theoretical results. Under these investigations, it can be concluded that theoretical results based on wave making resistance Coefficients, surface integrals of the square of free surface elevation and surface integrals of the square of free surface disturbance function have strong elations to wave breaking surface areas.

Takanori Hino – 2nd expert on this subject based on the ideXlab platform

  • study on bow shape optimization of ultra large Block Coefficient ship and cfd simulations of initial and optimized hull forms
    Journal of the Society of Naval Architects of Japan, 2014
    Co-Authors: Kazuo Suzuki, Takanori Hino

    Abstract:

    The present paper describes a hull form improvement of innovative low-speed Ultra Large Block Coefficient Ship (ULBS). A hull form optimization method for reducing wave-making resistance and wave-breaking at the bow using nonlinear programming method (NLP) based on the Rankine source method is discussed. In the optimization process, wave-making resistance Coefficient,surface integrals of the square of free surface elevations and free surface disturbance function D(x,y)-values are selected as the objective functions. Bow-body shape is optimized under the prescribed design constraints based on the present method. Numerical examples are given for unconventional ULBS. The three improved hull forms for the corresponding objective functions are obtained by optimal designs which indicate that the objective functions are reduced distinctly. In order to verify the present optimization method based on the potential solver, the flow characteristics around the initial and bow optimized hull forms are analyzed by using Computational Fluid Dynamics (CFD) analysis based on the Navier-Stokes (NS) solver. Comparisons of the computed resistance Coefficients, pressure and velocity distributions of the initial and bow optimized hull forms are presented. It is confirmed that simulation results based on the viscous flow solver show reasonable agreements with the numerical results based on the Rankine source method for the bow optimized hull forms.

  • proposal of ultra large Block Coefficient ship and fundamental studies on its bow wave breaking
    Journal of the Japan Society of Naval Architects and Ocean Engineers, 2013
    Co-Authors: Kazuo Suzuki, Takanori Hino

    Abstract:

    Due to the increase of maritime transportation volume day by day it is necessary to design a ship hull having large carrying capacity with low resistance. For this purpose, the authors propose innovative concepts of Ultra Large Block Coefficient Ship (ULBS). In this paper, its concepts and study plans are shown, and its bow wave breaking phenomena are investigated as one of the fundamental studies on ULBS hull form. As experimental studies, wave breaking surface areas caused by ULBS models are measured. As theoretical ones, wave making resistance Coefficients and distributions of free surface elevation are evaluated by means of Rankine source method, and distributions of free surface disturbance function D(x,y) are evaluated by means of Baba’s low speed theory. Various parameters related to the wave breaking phenomena are investigated in comparisons between experimental and theoretical results. Under these investigations, it can be concluded that theoretical results based on wave making resistance Coefficients, surface integrals of the square of free surface elevation and surface integrals of the square of free surface disturbance function have strong elations to wave breaking surface areas.

Jouchien Chang – 3rd expert on this subject based on the ideXlab platform

  • edge preservance and Block effect reduction by Block Coefficient diffusion method
    Signal Processing, 1997
    Co-Authors: Jouchien Chang

    Abstract:

    Abstract Image compression techniques have been used widely in a variety of applications. In the consideration of image quality and compression ratio, an efficient compression technique is expected. In this paper, we will present a transform-coding-based method by using adaptive classification and Coefficient-diffusion techniques to improve image-compression quality while maintaining compression ratio. Experiments are conducted on a wide variety of images. Experimental results reveal that both the image quality and the compression ratio are retained by applying the proposed method.