Abstract: The torsional effect of piezoelectric quartz wafer is first investigated. The torsional theory of circular quartz is deduced by using the anisotropic elasticity and Maxwell electromagnetic theory, then the stress field and electrostatic field is founded. The distribution of the electric field in the piezoelectric body is obtained by the finite element method. Based on theoretical analysis of the bound charge distribution, the measuring electrodes are effectively disposed on the surfaces of the piezoelectric body. As the result, the polar charge is linear with the torque. A satisfactory agreement is obtained between the computed results and experimental results. The analysis pro-vides the basis for the torque measuring technique on the single circular piezoelectric quartz.

Key words: Anisotropy, Nonlinear polarization, Piezoelectricity, Torsional effect, Φ-type wind turbine aerodynamic multiply stream-tubes model interference airflow