Fabrication of a New Wind Tunnel for Spinning Body Using Magnetic Suspension

A wind-tunnel system for spinning body has been proposed to measure hydrodynamic forces acting on the body. In the proposed system, a ferromagnetic sphere (body) is suspended and rotated by electromagnets. The forces acting on the body are measured from the control signal for suspension. In this work, a wind-tunnel system with 60 60? mm was fabricated. It has eight electromagnets placed around the wind-tunnel, and a newly fabricated 3-axis optical sensor that operates in the fully differential mode. Stable suspension and three-dimensional positioning of the body were achieved in the developed system. Spinning of the body was realized by superimposing two-phase AC signals on the control signal. The hydrodynamic forces acting on the spinning body are measured successfully.