Student: Andrew Bodling, Graduate Student in Aerospace Engineering, Iowa State University
Faculty Mentor: Dr. Anupam Sharma
Numerical Investigations of Bio-Inspired Blade Designs
Noise generated from wind turbines and jet engines can be a real nuisance to anyone living nearby them and is a serious issue to address to allow people residing near them to accept their presence. I am currently working with Dr. Anupam Sharma, professor of Iowa State University, where we are seeking to solve the noise problem by taking a bio-inspired approach. We are researching the nocturnal owl to understand what makes the bird so quiet during flight in an effort to create nearly silent aircraft, UAVs and wind turbines.
Previous experiments have modeled one of the pertinent anatomical features of the owl, the soft downy coat, with an array of “finlets” attached to the trailing edge of an airfoil. By using the finlets, the trailing edge noise was attenuated significantly. In our research we are seeking to better understand the noise reduction mechanisms of the finlets by using high fidelity simulations. The modeling methodology used to simulate the finlet geometry showed noise reductions with the finlets that qualitatively agreed with the experimental data. Contour plots of normalized turbulence kinetic energy are compared between the baseline and finlet simulation in the figure on the right. With the finlet geometry, the TKE close to the airfoil surface (trailing edge) is substantially reduced with the finlets, and appears to be concentrated above the finlets. The figure clearly indicates that the separation distance between the source (unsteadiness in the turbulence) and the scattering airfoil trailing edge is increased. This result shows that one of the reasons for the observed noise reduction with finlets is the increased source-scattering edge separation distance, which makes the edge scattering process less efficient. Future research will look into other noise reduction mechanisms and simulate different geometries/flow conditions.