Aerodynamic sound production from flying beetles

Abstract

Extensions of previous research on the aerodynamic sound production by flying beetles are presented. The topic is of interest in terms of both fundamental acoustics and the applications such as classification and tracking of invasive insect species. High speed video with synchronous acoustics recordings of the Coconut Rhinoceros Beetle (Oryctes rhinoceros) and the Oriental Flower Beetle (Protaetia orientalis) provide experimental data for the analytical and numerical models. Three dimensional, unsteady flow simulations were conducted using compressible flow software (CAESIM, Adaptive Research, Inc.) with a TVD methodology. Flapping wing motion requires mesh deformation with a rotation with a prescribed bending and also coupled rotation and translation of the wing’s hinge position. Contributions of wing beat frequency and vorticity to sound generation are examined with respect assumptions of the spatial dimensions (two or three dimensional), bending and fluid structure interactions. Underlying sound generation mechanisms at the wing tips are examined in higher fidelity. Both hovering and forward flight are investigated and compared in terms of the different flapping motion of the two species. In addition, relationships of the tones to the temporal lift and drag lift coefficients are highlighted.