Huang, Fang Sheng Feng, Zhi Hua Ma, Yu Ting Pan, Qiao Sheng Zhang, Lian Sheng Liu, Yong Bin He, Liang Guo High-frequency performance for a spiral-shaped piezoelectric bimorph Adjustments to the distribution of stiffness along the radius of the bimorph could prevent this and allow for improved deflection without the risk of reaching higher modes. These higher node shapes sharply reduced the volume change and negatively impacted the velocity of the jet at those frequencies.

Those with lower stiffness allowed for greater displacement of the surface, initially increasing the volume change, but exhibited higher mode shapes at certain frequency ranges. Bimorphs with higher stiffness exhibited a more desirable (0,1) mode shape, which produced a high volume change inside of the actuator cavity.

Results from a bimorph of alternate stiffness were also compared. Phase-locked jet velocities and maps of displacement of the surface of the bimorph were compared between actuators of varying diameter. Knowledge of these could aid in refining the geometry of the cavity to improve efficiency. The velocity performance of synthetic jet actuators is dependent on this volume change and the associated internal pressure changes. The design of piezoelectric bimorphs for synthetic jet actuators could be improved by greater understanding of the deflection of the bimorphs both their mode shapes and the resulting volume change inside the actuator. Exploration of Piezoelectric Bimorph Deflection in Synthetic Jet Actuators

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