Spatial filter velocimetry based on time-series particle images

Hosokawa, Shigeo; Tomiyama, Akio

doi:10.1007/s00348-011-1259-z

Cited by 18 publications

(26 citation statements)

References 33 publications

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“…In this study, we use a cosine function for F SF , and a wavelet analysis is adopted to evaluate the frequency of I SF . Details of SFV can be found in Hosokawa and Tomiyama (2012).…”

Section: Principle Of Spatiotemporal Filter Velocimetrymentioning

confidence: 99%

“…Hence, an accurate measurement of interfacial shear stresses in both phases would enable us to evaluate the Marangoni stress. Imaging velocimetry such as PIV and spatiotemporal filter velocimetry (SFV; Hosokawa and Tomiyama 2012;Hosokawa et al, 2013) may provide velocity distributions in the vicinity of an interface. However, the presence of an interface in a measurement region decreases the measurement accuracy.…”

Section: Introductionmentioning

confidence: 99%

“…Since SFV measures velocity of a single particle in a fixed measurement region and does not use a spatial correlation process, it might be easily extended to an arbitrary measurement region fitted to an interface without transformation of particle images. Since accuracy of velocity measurement and spatial and temporal resolutions of SFV are as high as laser Doppler velocimetry (LDV) (Hosokawa and Tomiyama, 2012), extension of SFV to boundary fitted measurement region may be a promising way to accurate measurement of interfacial shear stress and the Marangoni stress at an interface.…”

Section: Introductionmentioning

confidence: 99%

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Experimental evaluation of Marangoni stress and surfactant concentration at interface of contaminated single spherical drop using spatiotemporal filter velocimetry

Hosokawa

Masukura

Hayashi

et al. 2017

International Journal of Multiphase Flow

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Spatiotemporal filter velocimetry (SFV) was extended to Lagrangian measurements with boundary-fitted measurement areas, and was applied to flows about single spherical drops of glycerol-water solution falling in stagnant silicon oil under clean and contaminated conditions to examine its applicability to the estimation of the Marangoni stress and surfactant concentration at a moving interface. Effects of bulk concentration of surfactant on the velocity field, the Marangoni stress and the surface concentration of surfactant were discussed from the measured data. As a result, we confirmed that accurate velocity distribution in the vicinity of the interface measured by SFV enables us to evaluate interfacial velocity and interfacial shear stresses and to estimate the Marangoni stress, interfacial tension and surfactant concentration at the interface with the assumption of negligible surface viscosity. The flow inside the drop and the interfacial velocity become weak due to the Marangoni stress caused by the gradient of surfactant concentration at the interface as the bulk concentration of surfactant increases. These results demonstrate that SFV is of great use in experimental analysis of adsorption and desorption kinetics at a moving interface.

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“…In this study, we use a cosine function for F SF , and a wavelet analysis is adopted to evaluate the frequency of I SF . Details of SFV can be found in Hosokawa and Tomiyama (2012).…”

Section: Principle Of Spatiotemporal Filter Velocimetrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental evaluation of Marangoni stress and surfactant concentration at interface of contaminated single spherical drop using spatiotemporal filter velocimetry

Hosokawa

Masukura

Hayashi

et al. 2017

International Journal of Multiphase Flow

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“…In addition, high-speed video cameras can be used to image the gas-liquid flow field. Hosokawa et al (2012a) used spatial filter velocimetry (SFV) based on spatial filtering of timeseries particle images proposed by Hosokawa and Tomiyama (2012b) to examine multiscale bubble velocity measurement. The edge detection process is added in the SFV processing to reduce the size of the image pattern and to obtain accurate velocity data; it demonstrated that SFV is able to measure bubble velocity in various spatial scales with higher accuracy than PIV and was successfully comparable to optical probe measurements.…”

Section: Introductionmentioning

confidence: 99%

Bubble Dynamics in 2d Bubble Column: Comparison Between High-Speed Camera Imaging Analysis and 4-Point Optical Probe

Ahmed

Sensenich

Gheni

et al. 2014

Chemical Engineering Communications

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Two-dimensional (2D) bubble columns have been used in the literature to study the detailed flow field for evaluation and validation of computational fluid dynamics (CFD) and for developing the needed closures and interfacial forces models for gas-water systems. Hence, this work focuses on investigating the bubble dynamics (i.e., local gas holdup, bubble velocity, bubble chord length, and frequency) in a 2D bubble column. Two advanced measurement techniques were implemented in this work, high-speed video camera imaging and a four-point optical probe. A new method for analysis of video camera imaging was employed. The results of both techniques were compared. The results show good overall agreement between the two methods for the horizontal profile of both bubble size and gas holdup. The findings revealed a strong positive correlation between bubble size and gas holdup. It was found that video image analysis could become an accurate, noninvasive alternative to fiber optical probes, at least in 2D systems, although the technique needs more refinement.

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“…SFV has been applied, for example in detecting surface velocities (Schaeper and Damaschke 2011), length (Bergmann 2010), fluid flow (Hosokawa and Tomiyama 2011), or the microcirculation of blood cells in the capillaries of human fingernail folds (Menn 2011). In the latter application, the shape of the spatial filter had to be adapted to the structure of the capillaries in the proximal nail folds of the fingers.…”

Section: Introductionmentioning

confidence: 99%

Optical high-resolution analysis of rotational movement: testing circular spatial filter velocimetry (CSFV) with rotating biological cells

Schaeper

Schmidt

Kostbade

et al. 2016

J. Phys. D: Appl. Phys.

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Circular spatial filtering velocimetry (CSFV) was tested during the microscopic registration of the individual rotations of baker's yeast cells. Their frequency-dependent rotation (electrorotation; ER) was induced in rotating electric fields, which were generated in a glass chip chamber with four electrodes (600 μm tip-to-tip distance). The electrodes were driven with sinusoidal quadrature signals of 5 or 8 V PP with frequencies up to 3 MHz. The observed cell rotation was of the order of 1-100 s per revolution. At each measuring frequency, the independent rotations of up to 20 cells were simultaneously recorded with a high-speed camera. CSFV was software-implemented using circular spatial filters with harmonic gratings. ER was proportional to the phase shift between the values of the spatial filtering signal of consecutive frames. ER spectra obtained by CSFV from the rotation velocities at different ER-field frequencies agreed well with manual measurements and theoretical spectra. Oscillations in the rotation velocity of a single cell in the elliptically polarized field near an electrode, which were resolved by CSFV, could not be visually discerned. ER step responses after field-on were recorded at 2500 frames per second. Analysis proved the high temporal resolution of CSFV and revealed a largely linear torque-friction relation during the acceleration phase of ER. Future applications of CSFV will allow for the simple and cheap automated high-resolution analysis of rotational movements where mechanical detection has too low a resolution or is not possible, e.g. in polluted environments or for gas and fluid vortices, microscopic objects, etc.

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Spatial filter velocimetry based on time-series particle images

Cited by 18 publications

References 33 publications

Experimental evaluation of Marangoni stress and surfactant concentration at interface of contaminated single spherical drop using spatiotemporal filter velocimetry

Experimental evaluation of Marangoni stress and surfactant concentration at interface of contaminated single spherical drop using spatiotemporal filter velocimetry

Bubble Dynamics in 2d Bubble Column: Comparison Between High-Speed Camera Imaging Analysis and 4-Point Optical Probe

Optical high-resolution analysis of rotational movement: testing circular spatial filter velocimetry (CSFV) with rotating biological cells

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