Nowadays, in Northern Europe, Japan, and USA, many researches have been presented about S. F. T.(Submerged Floating Tunnel) adapting for coastal and Fjords traffic systems. But the natural frequency of S. F. T. is below a few Hz because of three types support conditions that are tension-leg type, piling, and floating support type subjected steady and sinusoidal oscillating flow. So they said that we must consider about the fluid force. In this paper, we proposed the air spouting type actuator to reduce fluid force of S. F. T's main body in the sinusoidal oscillating flow. We testified effects of the control system for reducing fluid force acting on S. F. T. to measure CD, CM, CL, and phase angle between displacement and force experimentally. We found that this actuator reduce fluid force effectively at some parameters (Air Spouting Fraction, K. C., spouting pattern).
