Dynamic trajectory measurement of a strained cable excited by mean flow using an improved optical stereovision system

Experiments on a strained cable excited by mean flow in a hydrodynamic tunnel have been performed in Large Cavitation Tunnel (GTH) from DGA Hydrodynamics. Measurements of cable displacement have been performed by high speed imaging system. Particular optical configuration around tunnel section has imposed the development of a new calibration model to take into account dioptric distortion. Preliminary tests have been conducted to ensure calibration efficiency with large windows. Moreover, to track the cable displacement, a technique called “blind point tracking method” has been developed. This technique is presented and takes advantage of axi-symmetry of cable and from epipolar geometry properties. Thanks to these several developments, different behaviours of cable can be easily studied.