Spring 2025 MMAE Seminar Series: Sean Kearney

Time

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Locations

Rettaliata Engineering Center, Room 104 10 West 32nd Street Chicago, IL 60616
Headshot of Sean Kearney, professor of aerospace engineering at the University of Illinois at Urbana-Champaign

The Department of Mechanical, Materials, and Aerospace Engineering presents its spring 2025 seminar series featuring Sean Kearney, professor of aerospace engineering at the University of Illinois at Urbana-Champaign, who will present “CARS Diagnostics for Aerospace Sciences.” This seminar is open to the public and will take place on Wednesday, February 5, from 12:45–1:45 p.m. in room 104 of the Rettaliata Engineering Center.

Abstract

Coherent anti-Stokes Raman scattering (CARS) has a four-decade history of application in challenging reacting and high-speed flow environments for thermometry, multi-species detection, and pressure measurements. Since the mid-2000s, the method has evolved with advancements in laser sources, including ultrashort-pulse femtosecond lasers and high-speed pulse-burst systems. In this talk, we discuss three recent examples of CARS application to aerospace sciences, each with a different laser architecture. A generalized description of the working principles of the CARS technique and its sensitivity to temperature and gas composition is provided. Recent Nd:YAG/dye-laser based temperature/species measurements in ablation and nonequilibrium boundary layers in the University of Illinois Plasmatron X facility are presented. These measurements illustrate the CARS method’s performance at extreme temperatures as high as 5500 K, with an ability to determine species-specific nonequilibrium vibrational and rotational temperatures. Ultrashort-pulse one-dimensional CARS line imaging for compressible flows is introduced, and application for simultaneous temperature, pressure, and molecular-tagging velocimetry is demonstrated in an under-expanded air jet. The talk concludes with a summary of high-speed, 100-kHz CARS and molecular-tagging velocimetry with the pulse-burst laser for characterization of the Sandia free-piston shock tunnel.

Biography 

Sean Kearney is a professor of aerospace engineering at the University of Illinois at Urbana-Champaign, and currently holds a joint appointment with Sandia National Laboratories, where he has been a technical staff member for 24 years. He has applied laser-based diagnostics to a wide variety of national-security problems in combustion, fluid mechanics, and heat transfer, and has helped pioneer the use of ultrashort-pulse and burst-mode laser sources for reacting flow diagnostics. His most recent research foci have been development of pulse-burst laser diagnostics for impulsively driven experiments and CARS applications at the interface between dissociated air and ablating heat-shield materials for hypersonic flight. He holds M.S. and Ph.D. degrees in mechanical engineering from the University of Illinois at Urbana-Champaign and a Bachelor of Science in Mechanical Engineering from Clarkson University. Kearney is an associate fellow of AIAA, where he recently served as chair of AIAA’s Aerodynamic Measurement Technology technical committee.

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