The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Dianyuan Fan - One of the best experts on this subject based on the ideXlab platform.

  • Role of transverse-momentum currents in the optical Magnus Effect in free space
    Physical Review A, 2010
    Co-Authors: Hailu Luo, Shuangchun Wen, Weixing Shu, Dianyuan Fan
    Abstract:

    We establish a general vector field model to describe the role of transverse-momentum currents in the optical Magnus Effect in free space. As an analogy of the mechanical Magnus Effect, the circularly polarized wave packet in our model acts as the rotating ball, and its rotation direction depends on the polarization state. Based on this model, we demonstrate the existence of an optical polarization-dependent Magnus Effect which is significantly different from the conventional optical Magnus Effect in that light-matter interaction is not required. Further, we reveal the relation between transverse-momentum currents and the optical Magnus Effect, and find that such a polarization-dependent rotation is unavoidable when the wave packet possesses transverse-momentum currents. The physics underlying this intriguing Effect is the combined contributions of transverse spin and orbital currents. We predict that this Effect may be observed experimentally even in the propagation direction. These findings provide further evidence for the optical Magnus Effect in free space and can be extrapolated to other physical systems.

  • Role of transverse momentum currents in optical Magnus Effect in the free space
    2010
    Co-Authors: Hailu Luo, Shuangchun Wen, Weixing Shu, Dianyuan Fan
    Abstract:

    We establish a general vector field model to describe the role of transverse momentum currents in optical Magnus Effect in the free space. As an analogy of mechanical Magnus Effect, the circularly polarized wavepacket in our model acts as the rotating ball and its rotation direction depends on the polarization state. Based on the model we demonstrate the existence of a novel optical polarization-dependent Magnus Effect which is significantly different from the conventional optical Magnus Effect in that light-matter interaction is not required. Further, we reveal the relation between transverse momentum currents and optical Magnus Effect, and find that such a polarizationdependent rotation is unavoidable when the wavepacket possesses transverse momentum currents. The physics underlying this intriguing Effect is the combined contributions of transverse spin and orbital currents. We predict that this novel Effect may be observed experimentally even in the propagation direction. These findings provide further evidence for the optical Magnus Effect in the free space.

Jung Yul Yoo - One of the best experts on this subject based on the ideXlab platform.

  • Inverse Magnus Effect on a rotating sphere: when and why
    Journal of Fluid Mechanics, 2014
    Co-Authors: Jooha Kim, Haecheon Choi, Hyungmin Park, Jung Yul Yoo
    Abstract:

    In some specific conditions, a flying spinning ball deflects in a direction opposite to that predicted by the Magnus Effect, which is known as the inverse Magnus Effect. To elucidate when and why this Effect occurs, we measure the variations of the drag and lift forces on a rotating sphere and the corresponding flow field with the spin ratio (the ratio of the rotational velocity to the translational one). This counterintuitive phenomenon occurs because the boundary layer flow moving against the surface of a rotating sphere undergoes a transition to turbulence, whereas that moving with the rotating surface remains laminar. The turbulence energizes the flow and thus the main separation occurs farther downstream, inducing faster flow velocity there and generating negative lift force. Empirical formulae are derived to predict the location where the flow separates as a function of the Reynolds number and the spin ratio. Using the formulae derived, the condition for the onset of the inverse Magnus Effect is suggested based on the negative lift generation mechanism.

Yu. P. Bliokh - One of the best experts on this subject based on the ideXlab platform.

  • Topological spin transport of photons: the optical Magnus Effect and Berry phase
    Physics Letters A, 2004
    Co-Authors: K. Yu. Bliokh, Yu. P. Bliokh
    Abstract:

    The Letter develops a modified geometrical optics (GO) of smoothly inhomogeneous isotropic medium, which takes into account two topological phenomena: Berry phase and the optical Magnus Effect. Taking into account the correspondence between a quasi-classical motion of a quantum particle with a spin and GO of an electromagnetic wave in smoothly inhomogeneous media, we have introduced the standard gauge potential associated with the degeneracy in the wave momentum space. This potential corresponds to the magnetic-monopole-like field (Berry curvature), which causes the topological spin (polarization) transport of photons. The deviations of waves of right-hand and left-hand polarization occur in the opposite directions and orthogonally to the principal direction of motion. This produces a spin current directed across the principal motion. The situation is similar to the anomalous Hall Effect for electrons. In addition, a simple scheme of the experiment allowing one to observe the topological spin splitting of photons has been suggested.

  • modified geometrical optics of a smoothly inhomogeneous isotropic medium the anisotropy berry phase and the optical Magnus Effect
    Physical Review E, 2004
    Co-Authors: Yu. P. Bliokh
    Abstract:

    We present a modification of the geometrical optics method, which allows one to properly separate the complex amplitude and the phase of the wave solution. Appling this modification to a smoothly inhomogeneous isotropic medium, we show that in the first geometrical optics approximation the medium is weakly anisotropic. The refractive index, being dependent on the direction of the wave vector, contains the correction, which is proportional to the Berry geometric phase. Two independent eigenmodes of right-hand and left-hand circular polarizations exist in the medium. Their group velocities and phase velocities differ. The difference in the group velocities results in the shift of the rays of different polarizations (the optical Magnus Effect). The difference in the phase velocities causes an increase of the Berry phase along with the interference of two modes leading to the familiar Rytov law about the rotation of the polarization plane of a wave. The theory developed suggests that both the optical Magnus Effect and the Berry phase are accompanying nonlocal topological Effects. In this paper the Hamilton ray equations giving a unified description for both of these phenomena have been derived and also a novel splitting Effect for a ray of noncircular polarization has been predicted. Specific examples are also discussed.

  • Optical Magnus Effect as a consequence of Berry phase anisotropy
    Journal of Experimental and Theoretical Physics Letters, 2004
    Co-Authors: K. Yu. Bliokh, Yu. P. Bliokh
    Abstract:

    Presented in this work is a modified geometric optics of smoothly inhomogeneous isotropic medium, which takes into account weak anisotropy introduced by inhomogeneity. Pointed out is the common nature of two fundamental phenomena: Berry’s geometrical phase and the optical Magnus Effect, that is, propagation of rays of right and left circular polarization along different trajectories. Shown is that the former phenomenon can be explained by the difference in phase velocity of waves of right-hand and left-hand polarizations, while the latter one is the result of the difference in their group velocity. This work demonstrates that the optical Magnus Effect is quite a topological Effect that exclusively depends on the geometry of the system’s contour in the momentum space. We predict the Effect of the splitting of a ray of mixed polarization into two circularly polarized rays and propose a scheme for the experimental observation of this phenomenon.

  • Topological spin transport of photons: the optical Magnus Effect and Berry phase
    Physics Letters A, 2004
    Co-Authors: K. Yu. Bliokh, Yu. P. Bliokh
    Abstract:

    The paper develops a modified geometrical optics (GO) of smoothly inhomogeneous isotropic medium, which takes into account two topological phenomena: Berry phase and the optical Magnus Effect. By using the analogy between a quasi-classical motion of a quantum particle with a spin and GO of an electromagnetic wave in smoothly inhomogeneous media, we have introduced the standard gauge potential associated with the degeneracy in the wave momentum space. This potential corresponds to the Dirac-monopole-like field (Berry curvature), which causes the topological spin (polarization) transport of photons. The deviations of waves of right-hand and left-hand helicity occur in the opposite directions and orthogonally to the principal direction of motion. This produces a spin current directed across the principal motion. The situation is similar to the anomalous Hall Effect for electrons. In addition, a simple scheme of the experiment allowing one to observe the topological spin splitting of photons has been suggested.Comment: 4 pages, 1 figur

Yanhe Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Modeling and control of a Magnus-Effect-based ducted fan aerial vehicle
    International Journal of Control Automation and Systems, 2015
    Co-Authors: Qingming Hou, Jie Zhao, Yanhe Zhu, Yongsheng Gao, Hongzhe Jin
    Abstract:

    A ducted fan aerial vehicle model using Magnus Effect steering engine is proposed in this paper. This model utilizes a steering engine that comprises four cylinders that are symmetrically installed at the aft inside the duct. Interaction between the spinning cylinder surface and the duct jet flow causes the aerodynamic lift proportional to angular velocity of the cylinder. Therefore, operating range of the aerodynamic lift is guaranteed to be sufficiently wide. The efficiency of the proposed method is confirmed via numerical simulations on integrated flight dynamics developed in this study.

  • Discussion on improving Magnus Effect of cylinder based on CFD
    2013 IEEE International Conference on Mechatronics and Automation, 2013
    Co-Authors: Jie Zhao, Qingming Hou, Hongzhe Jin, Jihong Yan, Yanhe Zhu, Ge Li
    Abstract:

    The Magnus Effect is used in many fields. In this paper, the Magnus force generated by the cylinder is used to stabilize the ducted fan UAV. The cylinder's Magnus Effect is analyzed by on the Computational Fluid Dynamics (CFD) method and a improved shape of the cylinder is presented. The aerodynamic characteristics of the cylinder's Magnus Effect is analyzed by CFD software, FLUENT. The multi-objective optimization of the improved shape of the cylinder is conducted. In the optimization the response surface methodology(RSM) and Genetic Algorithm(GA) are adopted.

  • ICIA - Aerodynamic characteristics analysis and robustness analysis of ducted-fan UAV based on Magnus Effect
    2013 IEEE International Conference on Information and Automation (ICIA), 2013
    Co-Authors: Jie Zhao, Qingming Hou, Hongzhe Jin, Jihong Yan, Yanhe Zhu
    Abstract:

    In this paper, a new actuator system of the ducted-fan Uninhabited Aerial Vehicle(DFUAV) is presented. The actuator system consists of four rotary cylinders which are symmetrically installed at bottom of inside duct. The force used for attitude stabilization is generated by the interaction between the surface of rotary cylinder and the downwash, which is known as Magnus Effect. In this paper, the characteristics analysis of the presented DFUAV was simulated by Computational Fluid Dynamics (CFD) method, the controller based on the cascaded system modeling and the parameterization of thrust of DFUAV is designed and the robustness analysis is conducted.

  • CFD analysis of ducted-fan UAV based on Magnus Effect
    2012 IEEE International Conference on Mechatronics and Automation, 2012
    Co-Authors: Jie Zhao, Qingming Hou, Hongzhe Jin, Yanhe Zhu
    Abstract:

    Uninhabited Aerial Vehicle(UAV) has been developed quickly for decades and a new kind of VTOL(Vertical Take-Off and Landing)UAV which is called Ducted-Fan Uninhabited Aerial Vehicle attracts more and more attention. This paper presents a new structure of the ducted-fan UAV. In this vehicle, the actuator system consists of four rotary cylinders which are symmetrically installed at bottom of inside duct. The force used for attitude stabilization is generated by the interaction between the surface of cylinder and the downwash, which is known as Magnus Effect. In this paper, the aerodynamic characteristics of propeller-wing interaction for the ducted fan UAV were simulated numerically based on the Computational Fluid Dynamics (CFD) by means of sliding mesh technology.

Jie Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Modeling and control of a Magnus-Effect-based ducted fan aerial vehicle
    International Journal of Control Automation and Systems, 2015
    Co-Authors: Qingming Hou, Jie Zhao, Yanhe Zhu, Yongsheng Gao, Hongzhe Jin
    Abstract:

    A ducted fan aerial vehicle model using Magnus Effect steering engine is proposed in this paper. This model utilizes a steering engine that comprises four cylinders that are symmetrically installed at the aft inside the duct. Interaction between the spinning cylinder surface and the duct jet flow causes the aerodynamic lift proportional to angular velocity of the cylinder. Therefore, operating range of the aerodynamic lift is guaranteed to be sufficiently wide. The efficiency of the proposed method is confirmed via numerical simulations on integrated flight dynamics developed in this study.

  • Discussion on improving Magnus Effect of cylinder based on CFD
    2013 IEEE International Conference on Mechatronics and Automation, 2013
    Co-Authors: Jie Zhao, Qingming Hou, Hongzhe Jin, Jihong Yan, Yanhe Zhu, Ge Li
    Abstract:

    The Magnus Effect is used in many fields. In this paper, the Magnus force generated by the cylinder is used to stabilize the ducted fan UAV. The cylinder's Magnus Effect is analyzed by on the Computational Fluid Dynamics (CFD) method and a improved shape of the cylinder is presented. The aerodynamic characteristics of the cylinder's Magnus Effect is analyzed by CFD software, FLUENT. The multi-objective optimization of the improved shape of the cylinder is conducted. In the optimization the response surface methodology(RSM) and Genetic Algorithm(GA) are adopted.

  • ICIA - Aerodynamic characteristics analysis and robustness analysis of ducted-fan UAV based on Magnus Effect
    2013 IEEE International Conference on Information and Automation (ICIA), 2013
    Co-Authors: Jie Zhao, Qingming Hou, Hongzhe Jin, Jihong Yan, Yanhe Zhu
    Abstract:

    In this paper, a new actuator system of the ducted-fan Uninhabited Aerial Vehicle(DFUAV) is presented. The actuator system consists of four rotary cylinders which are symmetrically installed at bottom of inside duct. The force used for attitude stabilization is generated by the interaction between the surface of rotary cylinder and the downwash, which is known as Magnus Effect. In this paper, the characteristics analysis of the presented DFUAV was simulated by Computational Fluid Dynamics (CFD) method, the controller based on the cascaded system modeling and the parameterization of thrust of DFUAV is designed and the robustness analysis is conducted.

  • CFD analysis of ducted-fan UAV based on Magnus Effect
    2012 IEEE International Conference on Mechatronics and Automation, 2012
    Co-Authors: Jie Zhao, Qingming Hou, Hongzhe Jin, Yanhe Zhu
    Abstract:

    Uninhabited Aerial Vehicle(UAV) has been developed quickly for decades and a new kind of VTOL(Vertical Take-Off and Landing)UAV which is called Ducted-Fan Uninhabited Aerial Vehicle attracts more and more attention. This paper presents a new structure of the ducted-fan UAV. In this vehicle, the actuator system consists of four rotary cylinders which are symmetrically installed at bottom of inside duct. The force used for attitude stabilization is generated by the interaction between the surface of cylinder and the downwash, which is known as Magnus Effect. In this paper, the aerodynamic characteristics of propeller-wing interaction for the ducted fan UAV were simulated numerically based on the Computational Fluid Dynamics (CFD) by means of sliding mesh technology.