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Odd M. Faltinsen - One of the best experts on this subject based on the ideXlab platform.
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Second-Order Diffraction and Radiation of a Floating Body With Small Forward Speed
Journal of Offshore Mechanics and Arctic Engineering, 2013Co-Authors: Yan-lin Shao, Odd M. FaltinsenAbstract:The formulation of the second-order wave-current-body problem in the Inertial Coordinate System involves higher-order derivatives in the body boundary condition. A new method taking advantage of the body-fixed Coordinate System in the near field is presented to avoid the calculation of higher-order derivatives in the body boundary condition. The new method has an advantage over the traditional method when the body surface has a sharp corner or high curvature. The nonlinear wave diffraction and forced oscillation of floating bodies are studied up to second order in wave slope. A small forward speed is taken into account. The results of the new method are compared with that of the traditional method based on a formulation in the Inertial Coordinate System. When the traditional method applies, good agreement has been obtained.
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Linear seakeeping and added resistance analysis by means of body-fixed Coordinate System
Journal of Marine Science and Technology, 2012Co-Authors: Yan-lin Shao, Odd M. FaltinsenAbstract:This paper presents an alternative formulation of the boundary value problem for linear seakeeping and added resistance analysis based on a body-fixed Coordinate System. The formulation does not involve higher-order derivatives of the steady velocity potential on the right-hand side of the body-boundary condition, i.e., the so-called m _ j -terms in the traditional formulation when an Inertial Coordinate System is applied. Numerical studies are made for a modified Wigley I hull, a Series 60 ship with block coefficient 0.7, and the S175 container ship for moderate forward speeds where it is thought appropriate to use the double-body flow as basis flow. The presented results for the forced heave and pitch oscillations, motion responses, and added resistance in head-sea waves show good agreement with experiments and some other numerical studies. A Neumann–Kelvin formulation is shown to give less satisfactory results, in particular for coupled heave and pitch added mass and damping coefficients.
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Second-Order Diffraction and Radiation of a Floating Body With Small Forward Speed
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 3, 2010Co-Authors: Yan-lin Shao, Odd M. FaltinsenAbstract:The formulation of the second-order wave-current-body problem in the Inertial Coordinate System involves higher-order derivatives in the body boundary condition. A new method taking advantage of the body-fixed Coordinate System in the near field is presented to avoid the calculation of higher-order derivatives in the body boundary condition. The new method has advantage over the traditional method when the body surface is with sharp corner or high curvature. The nonlinear wave diffraction and forced oscillation of floating bodies are studied up to second order in wave slope. A small forward speed is taken into account. The results of the new method are compared with that of the traditional method based on a formulation in the Inertial Coordinate System. When the traditional method applies, good agreement has been obtained.Copyright © 2010 by ASME
Yan-lin Shao - One of the best experts on this subject based on the ideXlab platform.
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Second-Order Diffraction and Radiation of a Floating Body With Small Forward Speed
Journal of Offshore Mechanics and Arctic Engineering, 2013Co-Authors: Yan-lin Shao, Odd M. FaltinsenAbstract:The formulation of the second-order wave-current-body problem in the Inertial Coordinate System involves higher-order derivatives in the body boundary condition. A new method taking advantage of the body-fixed Coordinate System in the near field is presented to avoid the calculation of higher-order derivatives in the body boundary condition. The new method has an advantage over the traditional method when the body surface has a sharp corner or high curvature. The nonlinear wave diffraction and forced oscillation of floating bodies are studied up to second order in wave slope. A small forward speed is taken into account. The results of the new method are compared with that of the traditional method based on a formulation in the Inertial Coordinate System. When the traditional method applies, good agreement has been obtained.
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Linear seakeeping and added resistance analysis by means of body-fixed Coordinate System
Journal of Marine Science and Technology, 2012Co-Authors: Yan-lin Shao, Odd M. FaltinsenAbstract:This paper presents an alternative formulation of the boundary value problem for linear seakeeping and added resistance analysis based on a body-fixed Coordinate System. The formulation does not involve higher-order derivatives of the steady velocity potential on the right-hand side of the body-boundary condition, i.e., the so-called m _ j -terms in the traditional formulation when an Inertial Coordinate System is applied. Numerical studies are made for a modified Wigley I hull, a Series 60 ship with block coefficient 0.7, and the S175 container ship for moderate forward speeds where it is thought appropriate to use the double-body flow as basis flow. The presented results for the forced heave and pitch oscillations, motion responses, and added resistance in head-sea waves show good agreement with experiments and some other numerical studies. A Neumann–Kelvin formulation is shown to give less satisfactory results, in particular for coupled heave and pitch added mass and damping coefficients.
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Second-Order Diffraction and Radiation of a Floating Body With Small Forward Speed
29th International Conference on Ocean Offshore and Arctic Engineering: Volume 3, 2010Co-Authors: Yan-lin Shao, Odd M. FaltinsenAbstract:The formulation of the second-order wave-current-body problem in the Inertial Coordinate System involves higher-order derivatives in the body boundary condition. A new method taking advantage of the body-fixed Coordinate System in the near field is presented to avoid the calculation of higher-order derivatives in the body boundary condition. The new method has advantage over the traditional method when the body surface is with sharp corner or high curvature. The nonlinear wave diffraction and forced oscillation of floating bodies are studied up to second order in wave slope. A small forward speed is taken into account. The results of the new method are compared with that of the traditional method based on a formulation in the Inertial Coordinate System. When the traditional method applies, good agreement has been obtained.Copyright © 2010 by ASME
V. V. Bobylev - One of the best experts on this subject based on the ideXlab platform.
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Residual HCRF Rotation relative to the Inertial Coordinate System
Astronomy Letters, 2015Co-Authors: V. V. BobylevAbstract:VLBI measurements of the absolute proper motions of 23 radio stars have been collected from published data. These are stars with maser emission, or very young stars, or asymptotic-giant-branch stars. By comparing these measurements with the stellar proper motions from the optical catalogs of the Hipparcos Celestial Reference Frame (HCRF), we have found the components of the residual rotation vector of this frame relative to the Inertial Coordinate System: (\omega_x,\omega_y,\omega_z) = (-0.39,-0.51,-1.25)+/-(0.58,0.57,0.56) mas/yr. Based on all the available data, we have determined new values of the components of the residual rotation vector for the optical realization of the HCRF relative to the Inertial Coordinate System: (\omega_x,\omega_y,\omega_z) = (-0.15,+0.24,-0.53)+/-(0.11,0.10,0.13) mas/yr.
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residual hcrf rotation relative to the Inertial Coordinate System
Astronomy Letters, 2015Co-Authors: V. V. BobylevAbstract:VLBI measurements of the absolute proper motions of 23 radio stars have been collected from published data. These are stars with maser emission, or very young stars, or asymptotic-giant-branch stars. By comparing these measurements with the stellar proper motions from the optical catalogs of the Hipparcos Celestial Reference Frame (HCRF), we have found the components of the residual rotation vector of this frame relative to the Inertial Coordinate System: (ωx, ωy, ωz) = (−0.39, −0.51, −1.25) ± (0.58, 0.57, 0.56) mas yr−1. Based on all the available data, we have determined new values of the components of the residual rotation vector for the optical realization of the HCRF relative to the Inertial Coordinate System: (ωx, ωy, ωz) = (−0.15, +0.24,−0.53) ± (0.11, 0.10, 0.13) mas yr−1.
Jian-miin Liu - One of the best experts on this subject based on the ideXlab platform.
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Localization of Lorentz transformation and its induced local Lorentz invariance
arXiv: General Physics, 2003Co-Authors: Jian-miin LiuAbstract:Introducing the primed Inertial Coordinate System, for each Inertial frame of reference, in addition to the usual Inertial Coordinate System, we assume that gravity-free space and time possess the Euclidean structures in the primed Inertial Coordinate System and the generalized Finslerian structures in the usual Inertial Coordinate System. We combine these assumptions with two fundamental postulates, (i) the principle of relativity and (ii) the constancy of the speed of light in all Inertial frames of reference, to derive the localized Lorentz transformation as a linear transformation between any two usual Inertial Coordinate Systems. Based on this, it is proposed that all laws of physics are locally Lorentz-invariant in the usual Inertial Coordinate System. As a Lorentz-invariant law of physics must be locally Lorentz-invariant while a locally Lorentz-invariant law is not necessarily Lorentz-invariant, the change from the requirement of Lorentz invariance to that of the local Lorentz invariance on laws of physics provides with a larger acceptable scope to explore these laws.
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Modification of special relativity and formulation of convergent and invariant quantum field theory
Chaos Solitons & Fractals, 2001Co-Authors: Jian-miin LiuAbstract:Abstract Besides two fundamental postulates, (i) the principle of relativity and (ii) the constancy of the speed of light in all Inertial frames of reference, the special theory of relativity uses another assumption. This other assumption concerns the Euclidean structure of gravity-free space and the homogeneity of gravity-free time in the usual Inertial Coordinate System. Introducing the primed Inertial Coordinate System, in addition to the usual Inertial Coordinate System, for each Inertial frame of reference, we assume the Euclidean structures of gravity-free space and time in the primed Inertial Coordinate System and their generalized Finslerian structures in the usual Inertial Coordinate System. We combine the alternative assumption with the two postulates (i) and (ii) to modify the special theory of relativity. The modified special relativity theory involves two versions of the light speed, infinite c′ in the primed Inertial Coordinate System and finite c in the usual Inertial Coordinate System. It also involves the c′-type Galilean transformation between any two primed Inertial Coordinate Systems and the localized Lorentz transformation between two corresponding usual Inertial Coordinate Systems. Since all our experimental data are collected and expressed in the usual Inertial Coordinate System, the physical principle is: the c′-type Galilean invariance in the primed Inertial Coordinate System plus the transformation from the primed Inertial Coordinate System to the usual Inertial Coordinate System. This principle is applied to a reformulation of mechanics, field theory and quantum field theory. Relativistic mechanics in the usual Inertial Coordinate System is unchanged, while field theory is developed and divergence-free. Any c′-type Galilean-invariant field System can be quantized by using the canonical quantization method in the primed Inertial Coordinate System. We establish a transformation law for quantized field Systems as they are transformed from the primed to the usual Inertial Coordinate System. It is shown that the modified special relativity theory, together with quantum mechanics, leads to a convergent and invariant quantum field theory, in full agreement with experimental facts. The formulation of this quantum field theory does not demand departures from the concepts such as local Lorentz invariance in the usual Inertial Coordinate System, locality of interactions, and local or global gauge symmetries.
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Modification of special relativity and local structures of gravity-free space and time
Chaos Solitons & Fractals, 2001Co-Authors: Jian-miin LiuAbstract:Besides two fundamental postulates, (i) the principle of relativity and (ii) the constancy of the speed of light in all Inertial frames of reference, special relativity uses the assumption about the Euclidean structures of gravity-free space and time in the usual Inertial Coordinate System. Introducing the so-called primed Inertial Coordinate System, in addition to the usual Inertial Coordinate System, for each Inertial frame of reference, we assume the Euclidean structures of gravity-free space and time in the primed Inertial Coordinate System and their generalized Finslerian structures in the usual Inertial Coordinate System. We combine this assumption with the two postulates (i) and (ii) to modify special relativity.
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Modification of special relativity and the divergence problem in quantum field theory
arXiv: General Physics, 1999Co-Authors: Jian-miin LiuAbstract:The root of the divergence problem in the current quantum field theory seems to be in the special theory of relativity. Here we propose a modified special relativity theory by introducing the primed Inertial Coordinate System, in addition to the usual Inertial Coordinate System, for each Inertial frame of reference, assuming the flat structures of gravity-free space and time in the primed Inertial Coordinate System and their generalized Finslerian structures in the usual Inertial Coordinate System, and combining this assumption with the two fundamental postulates, (i) the principle of relativity and (ii) the constancy of the one-way speed of light in all Inertial frames of reference. The modified special relativity theory involves two versions of the light speed, infinite speed c-prime in the primed Inertial Coordinate System and finite speed c in the usual Inertial Coordinate System. The physical principle is: the c-prime-type Galilean invariance in the primed Inertial Coordinate System plus the transformation from the primed to the usual Inertial Coordinate Systems. The modified special relativity theory and the quantum mechanics theory together found a convergent and invariant quantum field theory.
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On local structures of gravity-free space and time
arXiv: General Physics, 1999Co-Authors: Jian-miin LiuAbstract:Besides two fundamental postulates, (i) the principle of relativity and (ii) the constancy of the one-way speed of light in all Inertial frames of reference, the special theory of relativity uses the assumption about the Euclidean structure of gravity-free space and the homogeneity of gravity-free time in the usual Inertial Coordinate System. Introducing the so-called primed Inertial Coordinate System, in addition to the usual Inertial Coordinate System, for each Inertial frame of reference, we assume the flat structures of gravity-free space and time in the primed Inertial Coordinate System and, hence, their generalized Finslerian structures in the usual Inertial Coordinate System. We further modify the special theory of relativity by combining the alternative assumption with the two postulates (i) and (ii). The modified special relativity theory involves two versions of the light speed, infinite speed c-prime in the primed Inertial Coordinate System and finite speed c in the usual Inertial Coordinate System. It involves the c-prime-type Galilean transformation between any two primed Inertial Coordinate Systems and the localized Lorentz transformation between any two usual Inertial Coordinate Systems. The physical principle in the modified special relativity theory is: the c-prime-type Galilean invariance in the primed Inertial Coordinate System plus the transformation from the primed to the usual Inertial Coordinate Systems. It combines with the quantum mechanics theory to found a convergent and invariant quantum field theory. We produce corrections to the Maxwellian velocity and velocity rate distributions for free particles. The detection of velocity and velocity rate distributions for free particles can serve as the tests to investigate the local structures of gravity-free space and time.
Rafael Wisniewski - One of the best experts on this subject based on the ideXlab platform.
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Control of rotational motion with application to spacecraft attitude
Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 1Co-Authors: Rafael WisniewskiAbstract:The paper adopts the energy shaping method to rotational motion control of a spacecraft. The configuration manifold considered in this paper is the 3-sphere. The quaternion and its conjugate momentum are used for global representation of motion in the canonical form. The design algorithm presented is validated for three typical attitude control objectives: stabilization in an Inertial Coordinate System, slew maneuver with obstacle avoidance, and active vibration damping for a low Earth orbit spacecraft.