Events

Rodrigo Sanchez-Gonzalez is an Assistant Professor of Chemistry at St. Olaf College.

Numerous flowfields related to combustion and high-speed flight are characterized by non-equilibrium effects, and the acquisition of fundamental information to describe and model fluid behavior is required to drive technological advances in these fields. A detailed description of molecular non-equilibrium effects on turbulence requires systematic integration between theoretical modeling and experimentation that directly relates model parameters to experimental observables.

The first part of this presentation will describe the development of a laser diagnostic technique proposed as a non-intrusive method to provide measurements of instantaneous fluctuations in velocity and temperature in gaseous flowfields. This technique is capable of instantaneous three-component velocimetry and thermometry in a gaseous flowfield by combining two Nitric Oxide Planar Laser Induced Fluorescence (NO PLIF) methods: Molecular Tagging Velocimetry (MTV) and two-line thermometry, employing the nascent NO(v''=1) arising from NO₂ photodissociation as a molecular tracer.

In the second part, I will discuss work in progress in the area of image processing applied to MTV data. Despite the potential of MTV methods for the study of high-speed flows, a number of factors that include the lack of ready-to-use data analysis codes, which are largely written in-house, have limited their application. A method to analyze of MTV image pairs to estimate quantities such as vorticity as well as pressure and density fluctuations, in addition to space-resolved velocity, will be discussed. This method involves proper image transformations to map an entire MTV grid distorted by the flow velocity onto the first perfect grid. This would increase the potential use of MTV methods to study turbulent flowfields, the direct measurement of vorticity, and overall increased spatial resolution.

Hosted by the Carleton College Chemistry Department.