An Inverse Problem Approach to Micro-PIV for Investigating Tiny Insect Flight Aerodynamics

Tiny insects are surprisingly good flyers, but their aerodynamics are poorly understood because they are so small. Understanding their flight aerodynamics and abilities could lead to improved micro-aerial vehicle designs and new control strategies for agricultural pests. Measurements of the flow around flying tiny insects could help, but measurements are challenging because of the insects’ small size and because they beat their wings hundreds of times per second. This project will develop and validate a new approach to measuring flow based on techniques that improve imaging at small scales. The approach will be applied to measure the flow around a variety of tiny insect species. Results will lead to new understandings about tiny insect flight aerodynamics. This project also includes development and dissemination of new flow measurement software and mentoring of undergraduate and graduate students in an interdisciplinary environment that blends fluid dynamics, biology, computational imaging, and artificial intelligence. This project will support the advancement of artificial intelligence and advanced manufacturing of aerodynamic vehicles. The aerodynamics of tiny insect flight is poorly understood but is thought to rely on drag and unsteady flow for lift generation. Flow measurements of freely flying insects are needed to elucidate their aerodynamics and validate prior computational models, but such measurements are challenging owing to the minute time and length scales of tiny insect flight. The objective of this project is to develop and validate a brightfield micro-particle image velocimetry system capable of performing these measurements. Crucially, this system incorporates insights from the field of imaging inverse problems to address one of the biggest shortcomings of brightfield micro-particle image velocimetry systems, namely a low signal-to-noise ratio arising from the out-of-focus particles along the line of sight. This novel system will be validated using experiments that compare measured velocity profiles in milli-fluidic channels to analytically known solutions at various magnifications. The validated system will then be automated and extended to enable it to perform three-dimensional flow measurements. Finally, this technique will be applied to measure the flow around five tiny insect species that fly at various Reynolds numbers with different wing morphologies. The knowledge gained from this project may lead to improved designs for tiny micro-aerial vehicles and to better control strategies for agricultural pests. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.