Recent progress in high-speed laser diagnostics for hypersonic flows

N Jiang, PS Hsu, M Gragston, S Roy - Applied Optics, 2023 - opg.optica.org
The recent progress in high-speed (≥ 100k H z) laser diagnostics for hypersonic flows is
reviewed. Owing to the ultrahigh flow speed, a laser frequency of 100 kHz or higher is …

Quantitative focused laser differential interferometry with hypersonic turbulent boundary layers

EK Benitez, MP Borg, J Luke Hill, MT Aultman… - Applied Optics, 2022 - opg.optica.org
The effect of turbulent wind-tunnel-wall<? TeX 2pc 0pt?> boundary layers on density change
measurements obtained with focused laser differential interferometry (FLDI) was studied …

Detection of second-mode instabilities on a flared cone in Mach 6 quiet flow with linear array focused laser differential interferometry

M Gragston, F Siddiqui, JD Schmisseur - Experiments in Fluids, 2021 - Springer
In this work, an enhanced version of the focused laser differential interferometer (FLDI) is
used to measure second-mode instabilities in the boundary layer on a flared cone in Mach 6 …

Focused Laser Differential Interferometry: Recent Developments and Applications for Flow Measurements

EK Benitez, A Ceruzzi, M Gragston… - AIAA SCITECH 2025 …, 2025 - arc.aiaa.org
Focused laser differential interferometry (FLDI), first introduced in the 1970s, has developed
into a powerful tool for the analysis of turbulent dynamics and fluctuations in fluid flows …

Measurement of wall-cooling effects on hypersonic boundary-layer transition using focused laser differential interferometry

F Siddiqui, M Gragston, RDW Bowersox - AIAA Journal, 2022 - arc.aiaa.org
The boundary layer on a sharp-tip, partially flared, actively cooled cone with discrete
roughness elements has been studied in a quiet Mach 6 wind tunnel using linear array …

Mack-mode instabilities on a cooled flared cone with discrete roughness elements at Mach 6

F Siddiqui, M Gragston, WS Saric, RDW Bowersox - Experiments in Fluids, 2021 - Springer
Boundary-layer transition, and the increased heating that accompanies it, has a great effect
on how hypersonic vehicles and projectiles are designed. The Mack-mode instability is the …

Correlated off-body density fluctuations and surface heating in hypersonic boundary layer transition

F Siddiqui, S Ledbetter, J Shine, RDW Bowersox… - Experiments in …, 2023 - Springer
Measurements of surface heat flux via IR thermography and boundary layer density
fluctuations using a variation of focused laser differential interferometry (FLDI) were …

Optical-axis spatial sensitivity of a simulated focused laser differential interferometer

EK Benitez, MP Borg, C Rhodes, JS Jewell - AIAA Journal, 2023 - arc.aiaa.org
A focused laser differential interferometer (FLDI) simulation was used to study the sensitivity
of the FLDI technique to a variety of factors. The model takes in a series of density fields and …

Simultaneous velocity profile and scalar spectra with linear array-focused laser differential interferometry

K Davenport, M Gragston - AIAA Journal, 2023 - arc.aiaa.org
FOCUSED-LASER differential interferometry (FLDI), first dis-cussed by Smeets and George
[1], allows for high-frequency (greater than1 MHz) nonintrusive flow disturbance …

Development of two-point focused laser differential interferometry for applications in high-speed wind tunnels

A Ceruzzi - 2022 - search.proquest.com
Focused laser differential interferometry (FLDI) and its relative two-point focused laser
differential interferometry (2pFLDI) are completely non-intrusive (ie seedless) optical …