Magnetic Sail is one of in-space propulsion systems using the interaction between the solar wind and an artificial magnetic field. In order to reveal thrust performance of Magnetic Sail which has feasible scale of magnetosphere, scale model experiment of Magnetic Sail was conducted in laboratory using Magnetic Sail ground simulator which was arranged in the space science chamber at JAXA. Magnetic Sail scale model obtains magnetospheric size of L = 0.07m, and 0.47 N-thrust in laboratory. Also, thrust is increased by increasing of the magnetic moment of a coil. The scale model corresponds to 30-N-class magnetic-sail which produces 80 km-size magnetosphere in space.
Air turbulence has become a major cause of significant injuries and aircraft damages. We are pursuing the research and development of a practical airborne Doppler LIDAR that will detect air turbulence ahead of an aircraft in-flight and give advanced warning to pilots. Although a larger measurement range could be achieved by using higher powered laser, it implies larger and heavier devices which are not favorable for airborne applications. We use a wind velocity width to detect air turbulence and introduce a spectral fitting method which reduces measurement errors of the wind velocity width and extends the measurement range. This paper describes the effect of the detection of air turbulence using the wind velocity width estimated by the spectral fitting method.
Three-dimensional numerical simulation of the flow field around a NACA0012 airfoil at Reynolds number 10,000 was carried out to clarify three-dimensionalization process of the flow field around the airfoil at 7 degrees of angle of attack. The simulation results show a primary instability in a laminar separation bubble on the suction side which leads to subsequent nonlinear equilibrium. The feature of the most amplified velocity fluctuation was in good agreement with that predicted by the linear stability theory of free shear layer. The secondary instability begins near the end of the separation bubble which induces spanwise deformation of the boundary layer; thereby three-dimensionalization of the flow field breaks out.
The present paper deals with a new lamination theory to calculate electric current between two probes on Carbon Fiber Reinforced Plastic (CFRP) laminates. Unidirectional CFRP has strongly orthotropic electric conductance. When electric current is applied on a surface of a CFRP plates using two probes, the electric voltage field is uniform for thin CFRP plate and is not uniform in the cross section for thick CFRP. The electric current concentrates near the surface where the electric current is applied for thick CFRP laminates. In the present study, a lamination theory for thin CFRP laminates is discussed first. After that, a new lamination theory for thick CFRP laminates is proposed here. The theory for thick CFRP plates adopts non-uniform electric voltage in the thickness direction. For the non-thick and non-thin (middle thickness) CFRP plate, an approximation method is proposed here. To obtain the shape of the non-uniform voltage distribution, the analytical results of a thick single-ply of the previous paper is adopted as a contribution function to calculate the effective conductance of the thick CFRP laminate. Cross-sectional 2-D FEM analysis is used to obtain the contribution function for non-thick CFRP plates. The proposed methods are applied to two cases of a thick CFRP plate, and the results are compared with the 3-D FEM results. As a result, the new lamination theory is proved to be efficient for thick CFRP plates.