Fedotov G.

Low-frequency vibration is a source of noise disturbances distorting the signals of hydrophysical velocity field sensors [Fedotov G.A. Proceedings of the ICSV10, 2003, Vol.8, p.4279-4286]. The physical reason of this phenomenon lies in the difficulty of separation of two additive components in the observable signal of an individual sensor. The first one is a friendly signal caused by the fluid velocity fluctuations, the second component is a parasite caused by the sensor oscillations relative to the fluid. This work extends the theoretical and experimental investigations of the sensor systems immune to vibrations of the system carrier. The output signal of such system is a linear combination of the individual sensor signals. In the present paper, the systems of three conformal (flush-mounted) tangent flow velocity sensors installed on the surface of a rigid circular cylinder are considered. The sensitivity axes of all three sensors are oriented along the tangents to the circles, the sections of the cylinder. It is shown that the system of three sensors installed on one circle allows to compensate the noise disturbances induced by five of six vibrational degrees of freedom of the cylinder. The corresponding algorithms for coprocessing the signals of individual sensors are designed. The experimental results are presented for validation of the theoretical conclusions on partial compensation of the vibrational noise disturbances. The disposition of three sensors on two circles is less effective method (in comparison with the sensor disposition on one circle) because in this case the influence of two or three vibrational degrees of freedom remains uncompensated. Three conformal sensors form a complete vibration-proof system if the sensors are disposed on three circles on one generatrix of cylinder. Such sensor system allows to compensate the noise disturbances induced by all six vibrational degrees of freedom of the cylinder.