Super-resolution of time-resolved three-dimensional density fields of the B mode in an underexpanded screeching jet

C Lee, Y Ozawa, T Nagata, T Nonomura - Physics of Fluids, 2023 - pubs.aip.org
The estimation of time-resolved three-dimensional (3D) density fields of an underexpanded
jet at the nozzle pressure ratio of 2.42, a so-called “spatiotemporal super-resolution” was …

Forward and inverse modeling of depth-of-field effects in background-oriented Schlieren

JP Molnar, EJ LaLonde, CS Combs, O Léon, D Donjat… - AIAA journal, 2024 - arc.aiaa.org
This paper reports a novel cone-ray model of background-oriented schlieren (BOS) imaging
that accounts for depth-of-field effects. Reconstructions of the density field performed with …

Spatiotemporal superresolution measurement based on POD and sparse regression applied to a supersonic jet measured by PIV and near-field microphone

Y Ozawa, T Nagata, T Nonomura - Journal of Visualization, 2022 - Springer
The present study proposed the framework of the spatiotemporal superresolution
measurement based on the sparse regression with dimensionality reduction using the …

Single-pixel correlation applied to background-oriented schlieren measurement

H Sugisaki, C Lee, Y Ozawa, K Nakai, Y Saito… - Experiments in …, 2022 - Springer
A high-spatial resolution measurement system by the background-oriented schlieren (BOS)
method is proposed in this note. The single-pixel correlation method is applied for the image …

Formulation and demonstrations of three-dimensional background-oriented schlieren using a mirror for near-wall density measurements

M Akamine, S Teramoto, K Okamoto - Experiments in Fluids, 2023 - Springer
Three-dimensional background-oriented schlieren (3D-BOS) is an effective method for
reconstructing 3D density fields from optically measured data, but it has limitations in …

Modal analyses of double pulsed pressure-sensitive paint data of im**ing supersonic jet

E Li, Y Oka, Y Ozawa, T Nonomura - Journal of Visualization, 2024 - Springer
The surface pressure field generated by a supersonic im**ing jet on a vertical flat plate
was measured using a pressure-sensitive paint (PSP) and a double-pulsed laser. The Mach …

Demonstration and verification of exact DMD analysis applied to double-pulsed schlieren image of supersonic im**ing jet

K Ohmizu, Y Ozawa, T Nagata, T Nonomura… - Journal of …, 2022 - Springer
The exact dynamic mode decomposition (DMD) was applied to the nonsequential image
dataset obtained by the double-pulsed schlieren measurement of a supersonic im**ing …

Data assimilation of ideally expanded supersonic jet using rans simulation for high-resolution piv data

Y Ozawa, T Nonomura - Aerospace, 2024 - mdpi.com
Data assimilation using particle image velocimetry (PIV) and Reynolds-averaged Navier–
Stokes (RANS) simulation was performed for an ideally expanded supersonic jet flying at a …

Evaluation of optimization algorithms and noise robustness of sparsity-promoting dynamic mode decomposition

Y Iwasaki, T Nonomura, K Nakai, T Nagata… - IEEE …, 2022 - ieeexplore.ieee.org
In the present study, we organize the existing sparsity-promoting dynamic mode
decomposition (DMDsp) in terms of noise robustness, propose faster optimization algorithm …

Density field reconstruction from time-series schlieren images via extended phase-consistent dynamic mode decomposition

T Shigeta, T Nagata, T Nonomura - Experiments in Fluids, 2023 - Springer
The extended phase-consistent dynamic mode decomposition (DMD) method, which
reconstructs density fields from density gradient fields in multiple directions, was developed …