Structure Optimal Design and Performance Test of Airfoil Shear Probes

Airfoil shear probes are instruments used to measure the turbulent kinetic energy dissipation rate in the ocean. The cantilever beams and piezoelectric ceramics sheets are core components of shear probes. The former is the force transferring unit that amplifies the shear force acting on the probe tip. The latter is the piezoelectric transduction element that transforms force to electrical charges. As obbligato components for shear velocity measurement, both the cantilever beam and piezoelectric ceramics sheet have significant influence on the performances of the sensor. Optimizing the dimensions of the cantilever beam and the piezoelectric ceramics sheet could improve the measuring performance of the shear probe, such as sensitivity and resonance frequency. In this paper, multiobjective optimization algorithm is used to obtain the main design parameters of the shear probe with appropriate sensitivity and resonance frequency. Serial tests are conducted including the tap test and the calibration test to examine the resonance frequency in wet mode, and analyze the sensitivity of the probe, respectively. Soon afterward, the sea trials were carried out in the Western Pacific Ocean. The power spectrum from shear velocity data shows a good agreement with the Nasmyth spectrum. The experiments also testify the validity of the optimal design method of the shear probe.