In this week’s JASA Express Letters, researchers in Japan capture sound fields around musical triangles. They wanted to understand the physical properties of the triangle instrument, test assumptions about the contribution of the triangle shape, and capture clear documentation through pictures of the sound waves around the triangle. Using acousto-optic imaging to study detailed characteristics of sound vibration pattern, the team found results that suggest resonance may occur in the triangle's semi-open space.

Researchers in China model the motions of groups of manta rays to study how group dynamics affect their propulsion, studying different formations of three manta rays: in tandem, in a triangular setup with one manta ray in front leading two behind, and in an inverse triangular configuration with one manta ray trailing the other two. They found the tandem formation only significantly increases propulsion for the middle manta ray, and the two triangular setups result in overall decreased efficiency compared to a single swimmer on its own. These findings can help optimize formations for underwater vehicle operations.