Professor Noel Clemens has been selected to receive the 2022 AIAA (American Institute of Aeronautics and Astronautics) Aerodynamic Measurement Technology Award. The award, established in 1995, is presented annually to a researcher who has exhibited continued contributions and achievements toward the advancement of advanced aerodynamics flowfield and surface measurement techniques for research in flight and ground test applications. Clemens was selected “for the development and application of innovative laser-based imaging techniques to bring new insight into the physics of complex turbulent flows.”
Clemens, who has been a faculty member of the Department of Aerospace Engineering and Engineering Mechanics at UT Austin since 1993, focuses his research in the area of hypersonics, experimental gas dynamics, experimental methods and combustion. He specializes in measurement technology using laser imaging diagnostics to study mixing, combustion, ablation, shock/boundary layer interactions and other high-speed unsteady flows.
Throughout his career, Clemens has made many important contributions toward aerodynamic measurement technology, especially applications of planar imaging methods to challenging flow environments, such as hypersonic flows, mixing, combustion and plasmas. Achievements include multi-parameter measurements using a combination of techniques such as PIV (particle image velocimetry), PLIF (planar laser induced fluorescence), Rayleigh scattering, pressure sensitive paint, digital image correlation, and laser-induced incandescence. According to Google Scholar his published works have been cited over 6,500 times.
He is a pioneer in applying advanced diagnostics to supersonic and hypersonic flows. His group was the first to apply kilohertz PIV in supersonic flows, and the first to apply PIV to hypersonic flows. As they advanced the technology, pushing acquisition rates to higher and higher speeds, their work revealed new physical phenomena. His work in supersonic boundary layers revealed, for the first time, the presence of very large-scale coherent structures (“superstructures”) in the boundary layer, and their influence on shock-induced turbulent separation. His recent work involves using combined PIV, pressure sensitive paint and digital image correlation to understand the interaction between shock-induced turbulent separation unsteadiness and the vibration of compliant structures.
Clemens has made major contributions in scalar imaging, especially the planar laser-induced fluorescence technique. Together with collaborators from Sandia, he invented the krypton PLIF method, which enables measurements of a conserved scalar in reacting flows, and can be used as a non-toxic flow marker in high-speed wind tunnels. He also was the first to use the sublimation of solid-phase naphthalene to investigate ablation-products transport in hypersonic boundary layers. His innovation was to measure the dispersion of the ablation products with PLIF of gas-phase naphthalene. This work led to the first demonstration of simultaneous scalar-velocity measurements in hypersonic boundary layers.
A key aspect of Clemens’ work over the years has been to carefully quantify the effect of the measurement system on the quality of the measurements. In a series of papers his group quantified the effect of imaging system resolution, noise, filtering and aliasing, on the measured data. Using these results, Clemens was able to design unique experiments that enabled him to investigate the structure of the finest-scales of turbulence in both non-reacting and reacting flows.
Currently, Clemens is the director of the ULI FAST for Hypersonics Aerodynamics Measurements (AFOSR/NASA) that focuses on developing a new measurement technology for hypersonic flight. This novel technique will re-define sensing and analysis of hypersonic vehicles, and could eventually be applied to lower-speed aircraft as well. Learn more about all of his group’s current research projects on his website.
Clemens is a Fellow of AIAA and the American Physical Society. He is the winner of three AIAA Best Paper Awards, served as associate editor of the AIAA Journal for two years, and served as the Editor-in-Chief of Experiments in Fluids for three years. He served as the chair of the ASE/EM Department at UT Austin from 2012-2020 and holds the Clare Cockrell Williams Centennial Chair in Engineering.
The award, which includes a personalized certificate and engraved medal, will be presented to Clemens during the AIAA SciTech Forum Awards Ceremony in January of 2022.