The Experts below are selected from a list of 127347 Experts worldwide ranked by ideXlab platform
Chang-sup Lee - One of the best experts on this subject based on the ideXlab platform.
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Improved hydrodynamic analysis of marine propellers using a B-spline-based higher-order Panel Method
Journal of Marine Science and Technology, 2015Co-Authors: Gun-do Kim, Byoung-kwon Ahn, Ji-hye Kim, Chang-sup LeeAbstract:An improved hydrodynamic analysis of marine propellers based on a B-spline higher-order Panel Method is presented. The existing potential-based Panel Methods inevitably result in the degradation of the accuracy, especially near the trailing edge and the tip of the lift-generating surface. However, in the present Method, the order of the B-splines used to represent body geometries and potentials can be increased without limit and, hence, solutions of any order can be obtained. In addition, the wake roll-up phenomenon of the propeller is adopted and its effects are investigated. The alignment procedure which satisfies the kinematic and dynamic boundary conditions on the shedding wake surface has been investigated by taking a close look at the case of marine propellers. In this work, we show that wake roll-up modeling gives improved results for the flow of extreme tip such as r / R = 0.99. The present Method is validated by comparing it to the existing numerical and experimental results.
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A B-Spline Based Higher-Order Panel Method Applied to Marine Hydrodynamic Problems
Volume 6: Nick Newman Symposium on Marine Hydrodynamics; Yoshida and Maeda Special Symposium on Ocean Space Utilization; Special Symposium on Offshore, 2008Co-Authors: Chang-sup Lee, Byoung-kwon Ahn, Gun-do Kim, Hyun Yup Lee, Do-chun HongAbstract:A B-spline based higher order Panel Method (hereinafter, HiPan) is developed for the motion of bodies in ideal fluid, either of infinite extent or with free boundary surface. In this Method, both the geometry and the potential are represented by B-splines, and it guarantees more accurate results than most potential based Panel Methods. In the present work, we apply the HiPan, which differs with the works at MIT in evaluating the induction integrals, to two major marine hydrodynamic problems: analysis of propulsive performance of the marine propellers and the motion of the floating bodies on the free surface. The present HiPan is shown superior to the constant Panel Method (hereinafter, CoPan) in predicting flow quantities in the area of the thin trailing edge and blade tip of the propeller. Numerical results are validated by comparison with experimental measurements.Copyright © 2008 by ASME
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A SURFACE Panel Method FOR DESIGN OF HYDROFOILS
Journal of Ship Research, 1994Co-Authors: Chang-sup Lee, Young-gi Kim, Jung-chun SuhAbstract:A surface Panel Method treating a boundary-value problem of the Dirichlet type is presented to design a hydrofoil corresponding to a prescribed pressure distribution. An integral equation is derived from Green's theorem, giving a relation between the total potential of known strength and the unknown local flux. Upon discretization, a system of linear simultaneous equations is formed and solved for an assumed geometry. The pseudo local flux, present due to the incorrect positioning of the assumed geometry, plays a role of the geometry corrector, with which the new geometry is computed for the next iteration. Sample designs for a series of pressure distributions of interest are performed to demonstrate the fast convergence, effectiveness and robustness of the procedure. The Method is shown equally applicable to designing two- and three-dimensional hydrofoil geometry.
Gun-do Kim - One of the best experts on this subject based on the ideXlab platform.
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Improved hydrodynamic analysis of marine propellers using a B-spline-based higher-order Panel Method
Journal of Marine Science and Technology, 2015Co-Authors: Gun-do Kim, Byoung-kwon Ahn, Ji-hye Kim, Chang-sup LeeAbstract:An improved hydrodynamic analysis of marine propellers based on a B-spline higher-order Panel Method is presented. The existing potential-based Panel Methods inevitably result in the degradation of the accuracy, especially near the trailing edge and the tip of the lift-generating surface. However, in the present Method, the order of the B-splines used to represent body geometries and potentials can be increased without limit and, hence, solutions of any order can be obtained. In addition, the wake roll-up phenomenon of the propeller is adopted and its effects are investigated. The alignment procedure which satisfies the kinematic and dynamic boundary conditions on the shedding wake surface has been investigated by taking a close look at the case of marine propellers. In this work, we show that wake roll-up modeling gives improved results for the flow of extreme tip such as r / R = 0.99. The present Method is validated by comparing it to the existing numerical and experimental results.
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A B-Spline Based Higher-Order Panel Method Applied to Marine Hydrodynamic Problems
Volume 6: Nick Newman Symposium on Marine Hydrodynamics; Yoshida and Maeda Special Symposium on Ocean Space Utilization; Special Symposium on Offshore, 2008Co-Authors: Chang-sup Lee, Byoung-kwon Ahn, Gun-do Kim, Hyun Yup Lee, Do-chun HongAbstract:A B-spline based higher order Panel Method (hereinafter, HiPan) is developed for the motion of bodies in ideal fluid, either of infinite extent or with free boundary surface. In this Method, both the geometry and the potential are represented by B-splines, and it guarantees more accurate results than most potential based Panel Methods. In the present work, we apply the HiPan, which differs with the works at MIT in evaluating the induction integrals, to two major marine hydrodynamic problems: analysis of propulsive performance of the marine propellers and the motion of the floating bodies on the free surface. The present HiPan is shown superior to the constant Panel Method (hereinafter, CoPan) in predicting flow quantities in the area of the thin trailing edge and blade tip of the propeller. Numerical results are validated by comparison with experimental measurements.Copyright © 2008 by ASME
J. Ando - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of cavitating propeller and pressure fluctuation on ship stern using a simple surface Panel Method “SQCM”
Journal of Marine Science and Technology, 2013Co-Authors: T. Kanemaru, J. AndoAbstract:This paper presents a calculation Method for the pressure fluctuation induced by a cavitating propeller. This Method consists of two steps: the first step is the calculation of propeller sheet cavitation, and the second step is the calculation of pressure fluctuation on the ship stern. It is for practicality that we divide the Method into two steps but do not calculate these steps simultaneously. This Method is based on a simple surface Panel Method “SQCM” which satisfies the Kutta condition easily. The SQCM consists of Hess and Smith type source Panels on the propeller or cavity surface and discrete vortices on the camber surface according to Lan’s QCM (quasi-continuous vortex lattice Method). In the first step, the cavity shape is solved by the boundary condition based on the free streamline theory. In order to get the accurate cavity shape near the tip of the propeller blade, the cross flow component is taken into consideration on the boundary condition. In the second step, we calculate the cavitating propeller and the hull surface flow simultaneously so as to calculate the pressure fluctuation including the interaction between the propeller and the hull. At that time, the cavity shape is changed at each time step using the calculated cavity shape gotten by the first step. Qualitative agreements are obtained between the calculated results and the experimental data regarding cavity shape, cavity volume and low order frequency components of the pressure fluctuation induced by the cavitating propeller.
Byoung-kwon Ahn - One of the best experts on this subject based on the ideXlab platform.
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Improved hydrodynamic analysis of marine propellers using a B-spline-based higher-order Panel Method
Journal of Marine Science and Technology, 2015Co-Authors: Gun-do Kim, Byoung-kwon Ahn, Ji-hye Kim, Chang-sup LeeAbstract:An improved hydrodynamic analysis of marine propellers based on a B-spline higher-order Panel Method is presented. The existing potential-based Panel Methods inevitably result in the degradation of the accuracy, especially near the trailing edge and the tip of the lift-generating surface. However, in the present Method, the order of the B-splines used to represent body geometries and potentials can be increased without limit and, hence, solutions of any order can be obtained. In addition, the wake roll-up phenomenon of the propeller is adopted and its effects are investigated. The alignment procedure which satisfies the kinematic and dynamic boundary conditions on the shedding wake surface has been investigated by taking a close look at the case of marine propellers. In this work, we show that wake roll-up modeling gives improved results for the flow of extreme tip such as r / R = 0.99. The present Method is validated by comparing it to the existing numerical and experimental results.
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A B-Spline Based Higher-Order Panel Method Applied to Marine Hydrodynamic Problems
Volume 6: Nick Newman Symposium on Marine Hydrodynamics; Yoshida and Maeda Special Symposium on Ocean Space Utilization; Special Symposium on Offshore, 2008Co-Authors: Chang-sup Lee, Byoung-kwon Ahn, Gun-do Kim, Hyun Yup Lee, Do-chun HongAbstract:A B-spline based higher order Panel Method (hereinafter, HiPan) is developed for the motion of bodies in ideal fluid, either of infinite extent or with free boundary surface. In this Method, both the geometry and the potential are represented by B-splines, and it guarantees more accurate results than most potential based Panel Methods. In the present work, we apply the HiPan, which differs with the works at MIT in evaluating the induction integrals, to two major marine hydrodynamic problems: analysis of propulsive performance of the marine propellers and the motion of the floating bodies on the free surface. The present HiPan is shown superior to the constant Panel Method (hereinafter, CoPan) in predicting flow quantities in the area of the thin trailing edge and blade tip of the propeller. Numerical results are validated by comparison with experimental measurements.Copyright © 2008 by ASME
T. Kanemaru - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of cavitating propeller and pressure fluctuation on ship stern using a simple surface Panel Method “SQCM”
Journal of Marine Science and Technology, 2013Co-Authors: T. Kanemaru, J. AndoAbstract:This paper presents a calculation Method for the pressure fluctuation induced by a cavitating propeller. This Method consists of two steps: the first step is the calculation of propeller sheet cavitation, and the second step is the calculation of pressure fluctuation on the ship stern. It is for practicality that we divide the Method into two steps but do not calculate these steps simultaneously. This Method is based on a simple surface Panel Method “SQCM” which satisfies the Kutta condition easily. The SQCM consists of Hess and Smith type source Panels on the propeller or cavity surface and discrete vortices on the camber surface according to Lan’s QCM (quasi-continuous vortex lattice Method). In the first step, the cavity shape is solved by the boundary condition based on the free streamline theory. In order to get the accurate cavity shape near the tip of the propeller blade, the cross flow component is taken into consideration on the boundary condition. In the second step, we calculate the cavitating propeller and the hull surface flow simultaneously so as to calculate the pressure fluctuation including the interaction between the propeller and the hull. At that time, the cavity shape is changed at each time step using the calculated cavity shape gotten by the first step. Qualitative agreements are obtained between the calculated results and the experimental data regarding cavity shape, cavity volume and low order frequency components of the pressure fluctuation induced by the cavitating propeller.
