Ansell gains Young Investigator Award to study transition to turbulence
Assistant Prof. Phillip Ansell of Aerospace Engineering at Illinois recently has gained the second Young Investigator Award of his career, this time to shed light on a long-standing question about how flows transition from predictable, laminar states to disorganized, turbulent states.
The Army Research Office is funding Ansell’s research through the Young Investigator Program as a basic scientific investigation to understand this complex phenomenon.
“Turbulence is something that touches every part of our lives,” Ansell said. “We listen for turbulent sounds produced in flow through cardiovascular systems as a way to identify heart murmurs. Optical distortion due to atmospheric turbulence is the reason why stars seem to twinkle in the night sky. It’s an incredibly important process.
“It goes without saying that turbulent flows are quite complex. Within a turbulent flow, fluctuations and eddy structures emerge, covering a large distribution of spatial and temporal scales. What we’re looking to understand is how this distribution of scales is created during the process where the flow first transitions to turbulence,” Ansell continued.
“This understanding is important within aeronautics, since if we understand how these (flow) scales are produced, perhaps we can control or prevent their formation. (Turbulent) flows typically lead to higher drag. So, if we can better understand where the distribution of turbulent scales come from in the transition process, we may be able to interact with the flow in new ways to reduce turbulence and produce much more efficient, lower-drag, more economical vehicles.”
Ansell and his team will obtain experimental data by using the refractive index matching fluid facility in the Renewable Energy and Turbulent Environment laboratory of Mechanical Science and Engineering in collaboration with Assistant Prof. Leonardo Chamorro. This state-of-the-art measurement technology will allow the researchers to obtain detailed measurements of the flow characteristics that cannot be obtained from standard methods.
“We will get some really high quality optical non-intrusive data of the full transitional flow field,” Ansell said.
The data analysis tools Ansell will use will allow the investigators to parse the complex characteristics the flow field into simpler contributions that are easier to study, while still describing the full dynamics of the transitional flow.
“If we understand the pieces, we can reconstruct them all back together and say, ‘Ah, now I know what’s going on.’ We’re trying to do this with the initial disturbance in the flow and see how it evolves and forms other scales of interest in the flow.”
Ansell won a Young Investigator Award from the Air Force Office of Scientific Research (AFOSR) in 2015 for his work in understanding the unsteady flow associated with the onset of dynamic stall.