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 …

Interpreting single-point and two-point focused laser differential interferometry in a turbulent jet

AP Ceruzzi, CP Cadou - Experiments in Fluids, 2022 - Springer
Focused laser differential interferometry (FLDI) and its relative two-point FLDI (2pFLDI) are
used to make density fluctuation and velocity measurements, respectively, in a canonical …

Linear array focused-laser differential interferometry for single-shot multi-point flow disturbance measurements

M Gragston, T Price, K Davenport, Z Zhang… - Optics Letters, 2020 - opg.optica.org
In this Letter, a modification of the well-known focused-laser differential interferometer (FLDI)
is demonstrated, with the primary focus being increasing the number of probed locations …

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 …

Focused laser differential interferometric investigation of turbulent jet spectra

A Hameed, NJ Parziale - Journal of Spacecraft and Rockets, 2022 - arc.aiaa.org
In this work, a model of focused laser differential interferometry (FLDI) is derived by
incorporating the local intensity of each beam in an FLDI beam pair. We rederive some …

Measurements and analysis of hypersonic tripped boundary layer turbulence

KJ Hopkins, H Porat, TJ McIntyre, V Wheatley… - Experiments in …, 2021 - Springer
Surface roughness elements have been used to overcome the large prediction uncertainties
of hypersonic boundary layer transition. They provide the ability to force transition at short …

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 …

Significance of the smaller scales for hypersonic turbulent boundary layers with focused laser differential interferometry

EK Benitez, M Aultman, L Duan, GP Camillo… - Physics of …, 2024 - pubs.aip.org
While designed to suppress disturbances located away from its beam foci, focused laser
differential interferometry (FLDI) is known to have some integration of signals along its …

Direct background-oriented schlieren tomography using radial basis functions

H Cai, Y Song, Y Ji, Z Li, A He - Optics Express, 2022 - opg.optica.org
Background-oriented schlieren tomography (BOST) is effective for flow field measurement;
however, different from general computed tomography (CT), the BOST utilizes the deflection …