2021 年 38 巻 3 号 p. 380304-
This study presents a numerical evaluation of the levitation stabilities of samples in resonant acoustic fields with various reflector geometries and levitated sample radii. Contactless sample manipulation by sound is of great importance in the fields of analytical chemistry, biology, material engineering, and food science. The establishment of the levitation stability plays a critical role in the achievement of reliable acoustic sample manipulation in midair. To enhance the levitation stability in acoustic levitator, we focused on the effect of the reflector curvature radius and sample radius. We characterize the length scale of the reflector and sample radius by the wavelength of sound λ. The radii of curvature of the reflector were varied as 1λ, 1.5λ, 2λ, and ∞. The simulation results revealed that the reflector with the radius of curvature of 1.5λ yielded the best levitation stability to levitate the sample along the vertical direction and hold it along the horizontal direction. With the reflector of the curvature radius of 1.5λ, interactions between the sound fields for four different samples were simulated, and it was demonstrated that all cases were levitated in a stable manner. Our findings can provide deeper insights into contactless sample manipulations for increased sample manipulation stability.