Flexible flapping wings are an important component in several developing technologies with potential to benefit national infrastructure and welfare. For example, miniature robotic vehicles with flapping wings could be deployed to identify leaks in dense networks of pipes, to survey air quality, or even to artificially pollinate crops. Flapping wings could also be used to harvest energy and thus power a sensor network for specific applications. However, engineering tools are not sufficiently evolved to utilize flexible flapping wings for these emerging technologies. Methods currently used to predict the physics of flapping wings are inefficient, often requiring long time to estimate the performance of just a single flapping wing system. As such, they cannot be used for real-time control applications where the system must adapt rapidly to dynamic environmental conditions. The primary goal of this award is therefore to develop efficient and rapid experimental methods to predict the physics governing flapping flexible wings. Such methods will advance the design for flapping wing technologies. This award will support American Indian students recruited through Montana State University's EMPower program. It will also promote science, technology, engineering and math fields through public outreach activities including Montana State Family Science Day and National Biomechanics Day.
This project specifically aims to realize a reduced-order fluid-structure interaction model of flapping wings. Conventional fluid-structure interaction models rely on coupled finite element and computational fluid dynamics solvers, both which require considerable computational resources. Existing low-order approaches are typically restricted to rigid wings and cannot account for the aerodynamic forces that result from elastic structural deformation. The model developed through this work will deliver solution accuracy near that of high-fidelity solvers with the computational efficiency achieved by low-order methods. This model will be applied to study both artificial wings as well as real insect wings and will be realized by accomplishing the following objectives. First, wings will be geometrically, structurally, and aerodynamically characterized via a combination of micro-computed-tomography scans, computational fluid dynamics, experimental modal analysis, and model updating routines. Second, the fluid-structure interaction framework will be derived using a novel deformable blade element momentum approach. Deformed wing aerodynamics are accounted for efficiently through a predetermined look-up table of coefficients and dynamic correction factors that will be incorporated into the quasi-steady model as necessary. This low-order model will initially be benchmarked against direct high-fidelity computational simulation. Third, the model will be validated experimentally. A linkage mechanism will be used to generate flapping kinematics. Wing strain, aerodynamic forces and torques will be measured and compared to theoretic predictions. The expected outcome of this project is a robust fluid-structure interaction framework capable of supporting real-time control as well as parametric design of flapping, flexible wing technologies.
This project is jointly funded by CBET-Fluid Dynamics, the Established Program to Stimulate Competitive Research (EPSCoR), and BIO-IOS programs.
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.
