期刊,Journal of visualization 2025年28卷3期_国家学术搜索

A temporally adaptive particle tracking velocimetry using continuous-wave illumination for fused event-and frame-based cameras

Xin ZengJiajun CaoZhen LyuChuangxin He...

463-486页

查看更多>>摘要：This study introduces a temporally adaptive particle tracking velocimetry (PTV) technique through a novel hardware and data fusion strategy, integrating an event-based camera with a low-frequency (125 Hz) frame-based camera under continuous-wave (CW) illumination, which was named TA-E-PTV technique, enhancing the spatiotemporal resolution of particle velocity measurements. In this system, the tracer particles with different speeds are captured using different sampling rates by the temporally adaptive event-based camera, the low-frequency frame-based camera will provide offset correction for the event camera's particle center detection; then a super-time resolution TA-E-PTV strategy was developed by sliding the stacked image window during stacking images from event-based data after completing each process of spatially isometric particle tracking. The TA-E-PTV technique's effectiveness and accuracy were validated through experimental measurements of jet flows at Reynolds numbers of 4,400 at particle density of 0.0016 and 0.0063 particles per pixel (ppp), achieving temporally adaptive tracking across a frequency range of 25 to 1,000 Hz, coupled with high-spatiotemporal resolution. The time uncertainties were 72 us for 0.0016 ppp and 130 us for 0.0063 ppp, and the difference in mean speed is less than 6% when compared to the high-speed camera references. Additionally, the super-time-resolution TA-E-PTV strategy under the CW illumination has achieved a super-temporal resolution of 13.89 kHz for 0.0016 ppp and 7.69 kHz for 0.0063 ppp by controlling the time interval according to the read-out time delay. This low-cost, high-precision, and high-spatiotemporal resolution TA-E-PTV method is particularly suited for analyzing flows with large velocity gradients and holds significant potential for advancing experimental fluid mechanics.

原文链接:

NETL
NSTL
Springer Nature

A temporally adaptive particle tracking velocimetry using continuous-wave illumination for fused event-and frame-based cameras

Xin ZengJiajun CaoZhen LyuChuangxin He...

463-486页

查看更多>>摘要：This study introduces a temporally adaptive particle tracking velocimetry (PTV) technique through a novel hardware and data fusion strategy, integrating an event-based camera with a low-frequency (125 Hz) frame-based camera under continuous-wave (CW) illumination, which was named TA-E-PTV technique, enhancing the spatiotemporal resolution of particle velocity measurements. In this system, the tracer particles with different speeds are captured using different sampling rates by the temporally adaptive event-based camera, the low-frequency frame-based camera will provide offset correction for the event camera's particle center detection; then a super-time resolution TA-E-PTV strategy was developed by sliding the stacked image window during stacking images from event-based data after completing each process of spatially isometric particle tracking. The TA-E-PTV technique's effectiveness and accuracy were validated through experimental measurements of jet flows at Reynolds numbers of 4,400 at particle density of 0.0016 and 0.0063 particles per pixel (ppp), achieving temporally adaptive tracking across a frequency range of 25 to 1,000 Hz, coupled with high-spatiotemporal resolution. The time uncertainties were 72 us for 0.0016 ppp and 130 us for 0.0063 ppp, and the difference in mean speed is less than 6% when compared to the high-speed camera references. Additionally, the super-time-resolution TA-E-PTV strategy under the CW illumination has achieved a super-temporal resolution of 13.89 kHz for 0.0016 ppp and 7.69 kHz for 0.0063 ppp by controlling the time interval according to the read-out time delay. This low-cost, high-precision, and high-spatiotemporal resolution TA-E-PTV method is particularly suited for analyzing flows with large velocity gradients and holds significant potential for advancing experimental fluid mechanics.

原文链接:

NETL
NSTL
Springer Nature

Visualization of 3D vortical structures around free-falling rigid and porous plates

Mahmoud RastiJinho OhSe Chul Oh

487-494页

查看更多>>摘要：This study investigates the vortical structure around rigid and porous plates using time-resolved three-dimensional (3D) particle tracking velocimetry (4D-PTV). The shape of plates was square, 2 cm by 2 cm with a thickness of 2 mm. The rigid plate was made of PMMA, and the porous plate was made of fabrics. Both plates were released into a water-filled tank, and then, 4D-PTV measurements were made during free fall motions. Both plates show a zigzag motion, while the rigid plate moves two times faster than that of the porous plate. The 3D vortical structures were obtained by Q criterion using 3D instantaneous velocity field data around the moving plate. Hairpin vortex structures are generated with the first slanting motion of both plates. The hairpin packet structure on the rigid plate resembles with that of turbulent boundary layer. With detachment of vortical structure from the plate edge, the direction change was happened and then turn to the opposite slanting motion. The moving rigid plate has the secondary hairpin vortex consisting of two rolled-up secondary vortices and a hairpin-like vortex, whereas the porous plate has only a secondary hairpin vortex due to slow movement in water.

原文链接:

NETL
NSTL
Springer Nature

Visualization of 3D vortical structures around free-falling rigid and porous plates

Mahmoud RastiJinho OhSe Chul Oh

487-494页

查看更多>>摘要：This study investigates the vortical structure around rigid and porous plates using time-resolved three-dimensional (3D) particle tracking velocimetry (4D-PTV). The shape of plates was square, 2 cm by 2 cm with a thickness of 2 mm. The rigid plate was made of PMMA, and the porous plate was made of fabrics. Both plates were released into a water-filled tank, and then, 4D-PTV measurements were made during free fall motions. Both plates show a zigzag motion, while the rigid plate moves two times faster than that of the porous plate. The 3D vortical structures were obtained by Q criterion using 3D instantaneous velocity field data around the moving plate. Hairpin vortex structures are generated with the first slanting motion of both plates. The hairpin packet structure on the rigid plate resembles with that of turbulent boundary layer. With detachment of vortical structure from the plate edge, the direction change was happened and then turn to the opposite slanting motion. The moving rigid plate has the secondary hairpin vortex consisting of two rolled-up secondary vortices and a hairpin-like vortex, whereas the porous plate has only a secondary hairpin vortex due to slow movement in water.

原文链接:

NETL
NSTL
Springer Nature

Flow-induced oscillation dynamics of a U-shaped buckled membrane: a comparison with the leading-edge-clamped membrane

Zhen LyuWeiwei CaiBenlong WangYingzheng Liu...

495-509页

查看更多>>摘要：Flow-induced oscillations (FIOs) of flexible membranes offer significant potential for renewable energy harvesting, but the performance variations between different membrane configurations lack quantification. This study experimentally compares two representative membrane configurations: a leading-edge-clamped membrane and a U-shaped buckled membrane, by analyzing their FIO dynamics, strain energy distributions, and energy harvesting capabilities using event-based camera measurements. Results demonstrate that the leading-edge-clamped membrane initiates a large-amplitude flapping mode above a critical wind speed threshold (10.3 m/s), with both amplitude and frequency escalating with wind speed. In contrast, the U-shaped membrane exhibits two FIO modes: a low-amplitude stream wise oscillation mode below 7.5 m/s and a high-amplitude snap-through oscillation (STO) mode beyond this threshold. Strain energy analysis revealed distinct energy concentration patterns: the flapping mode of the leading-edge-clamped membrane exhibited energy focal points at 0.18L and 0.70L (L = membrane length), whereas the STO mode of the U-shaped buckled membrane demonstrated triple concentration peaks at 0.43L, 0.76L, and 0.97L positions. Crucially, the STO mode achieves a 9.75-fold maximum strain energy enhancement over the flapping of the leading-edge-clamped membrane, demonstrating its superior energy harvesting efficiency. These findings establish quantitative benchmarks for membrane harvester design and provide actionable insights for optimizing piezoelectric material placement through strain energy localization.

原文链接:

NETL
NSTL
Springer Nature

Flow-induced oscillation dynamics of a U-shaped buckled membrane: a comparison with the leading-edge-clamped membrane

Zhen LyuWeiwei CaiBenlong WangYingzheng Liu...

495-509页

查看更多>>摘要：Flow-induced oscillations (FIOs) of flexible membranes offer significant potential for renewable energy harvesting, but the performance variations between different membrane configurations lack quantification. This study experimentally compares two representative membrane configurations: a leading-edge-clamped membrane and a U-shaped buckled membrane, by analyzing their FIO dynamics, strain energy distributions, and energy harvesting capabilities using event-based camera measurements. Results demonstrate that the leading-edge-clamped membrane initiates a large-amplitude flapping mode above a critical wind speed threshold (10.3 m/s), with both amplitude and frequency escalating with wind speed. In contrast, the U-shaped membrane exhibits two FIO modes: a low-amplitude stream wise oscillation mode below 7.5 m/s and a high-amplitude snap-through oscillation (STO) mode beyond this threshold. Strain energy analysis revealed distinct energy concentration patterns: the flapping mode of the leading-edge-clamped membrane exhibited energy focal points at 0.18L and 0.70L (L = membrane length), whereas the STO mode of the U-shaped buckled membrane demonstrated triple concentration peaks at 0.43L, 0.76L, and 0.97L positions. Crucially, the STO mode achieves a 9.75-fold maximum strain energy enhancement over the flapping of the leading-edge-clamped membrane, demonstrating its superior energy harvesting efficiency. These findings establish quantitative benchmarks for membrane harvester design and provide actionable insights for optimizing piezoelectric material placement through strain energy localization.

原文链接:

NETL
NSTL
Springer Nature

A comparative study of table-sized physicalization and digital visualization

Yanxin WangYihan LiuLingyun YuChengtao Ji...

511-533页

查看更多>>摘要：Data physicalization is gaining popularity in public and educational contexts due to its potential to make data more tangible and understandable. Despite its growing use, there remains a significant gap in our understanding of how large-size physical visualizations compare to their digital counterparts in terms of user comprehension and memory retention. This study aims to bridge this knowledge gap by comparing the effectiveness of visualizing school building history data on large digital screens versus large physical models. Our experimental approach involved 32 participants who were exposed to one of the visualization mediums. We assessed their user experience and immediate understanding of the content, measured through tests after exposure, and evaluated memory retention with follow-up tests seven days later. The results revealed notable differences between the two forms of visualization: physicalization not only facilitated better initial comprehension but also significantly enhanced long-term memory retention. Furthermore, user feedback on usability was also higher on physicalization. These findings underscore the substantial impact of physicalization in improving information comprehension and retention. This study contributes crucial insights into future visualization media selection in educational and public settings.

原文链接:

NETL
NSTL
Springer Nature

A comparative study of table-sized physicalization and digital visualization

Yanxin WangYihan LiuLingyun YuChengtao Ji...

511-533页

查看更多>>摘要：Data physicalization is gaining popularity in public and educational contexts due to its potential to make data more tangible and understandable. Despite its growing use, there remains a significant gap in our understanding of how large-size physical visualizations compare to their digital counterparts in terms of user comprehension and memory retention. This study aims to bridge this knowledge gap by comparing the effectiveness of visualizing school building history data on large digital screens versus large physical models. Our experimental approach involved 32 participants who were exposed to one of the visualization mediums. We assessed their user experience and immediate understanding of the content, measured through tests after exposure, and evaluated memory retention with follow-up tests seven days later. The results revealed notable differences between the two forms of visualization: physicalization not only facilitated better initial comprehension but also significantly enhanced long-term memory retention. Furthermore, user feedback on usability was also higher on physicalization. These findings underscore the substantial impact of physicalization in improving information comprehension and retention. This study contributes crucial insights into future visualization media selection in educational and public settings.

原文链接:

NETL
NSTL
Springer Nature

Towards better illegal chemical facility detection with hazardous chemicals transportation trajectories

Junxiu TangHuimin RenZikun DengDi Weng...

535-551页

查看更多>>摘要：Unregistered illegal facilities that do not qualify for chemical production pose substantial threats to human lives and the environment. For human safety and environmental protection, the government needs to figure out the illegal facilities and shut them down. A new, convenient, and affordable approach to detect such facilities is to analyze the trajectories of hazardous chemicals transportation (HCT) trucks. The existing study leverages a machine learning model to predict how likely a place is illegal. However, such a model lacks interpretability and cannot provide actionable justifications required for decision-making. In this study, we collaborate with HCT experts and propose an interactive visual analytics approach to explore the suspicious stay points, analyze abnormal HCT truck behaviors, and figure out unregistered illegal chemical facilities. First, experts receive an initial result from the detection model for reference. Then, they are supported to check the detailed information of the suspicious places with three coordinated views. We apply a visualization that tightly encodes the geo-referred movement activities along the timeline to present the HCT truck behaviors, which can help experts finally verify their conclusions. We demonstrate the effectiveness of the system with two case studies on real-world data. We also received experts' positive feedback from an expert interview.

原文链接:

NETL
NSTL
Springer Nature

Towards better illegal chemical facility detection with hazardous chemicals transportation trajectories

Junxiu TangHuimin RenZikun DengDi Weng...

535-551页

查看更多>>摘要：Unregistered illegal facilities that do not qualify for chemical production pose substantial threats to human lives and the environment. For human safety and environmental protection, the government needs to figure out the illegal facilities and shut them down. A new, convenient, and affordable approach to detect such facilities is to analyze the trajectories of hazardous chemicals transportation (HCT) trucks. The existing study leverages a machine learning model to predict how likely a place is illegal. However, such a model lacks interpretability and cannot provide actionable justifications required for decision-making. In this study, we collaborate with HCT experts and propose an interactive visual analytics approach to explore the suspicious stay points, analyze abnormal HCT truck behaviors, and figure out unregistered illegal chemical facilities. First, experts receive an initial result from the detection model for reference. Then, they are supported to check the detailed information of the suspicious places with three coordinated views. We apply a visualization that tightly encodes the geo-referred movement activities along the timeline to present the HCT truck behaviors, which can help experts finally verify their conclusions. We demonstrate the effectiveness of the system with two case studies on real-world data. We also received experts' positive feedback from an expert interview.

原文链接:

NETL
NSTL
Springer Nature