Particle Image Velocimetry Analysis Research Articles

Abstract P2111: Hutchinson Gilford Progeria Patient-specific Induced Cardiomyocyte Model Carrying Lamin A Gene Variant C.1824 C > T

Background: Hutchinson-Gilford progeria (HGP) is a rare genetic disorder in which children age rapidly. They suffer from atherosclerosis, cardiovascular diseases, and strokes. The LMNA variant c.1824C>T accounts for ~90% of HGP cases. This variant causes an abnormal Lamin A protein called progerin. The detailed molecular mechanisms of Lamin A in the heart remain elusive due to the lack of appropriate in vitro models. Hypothesis: We hypothesize that HGP patient’s induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iCMCs) will provide a model platform to study the cardio-pathologic mechanisms associated with progeria. Methods and Results: We performed in silico analysis of LMNA variant c.1824C>T to determine its effects on Lamin A structure and stability. For validation , skin fibroblasts (SFs) from a de-identified HGP patient (hPGP1, proband) and parents were obtained from the Progeria Foundation. Through Sanger sequencing (Fig 1A) and restriction fragment length polymorphism, with enzyme EciI , targeting Lamin A, we characterized hPGP1-SFs as heterozygous mutants for variant c.1824 C>T. Then, we reprogrammed the three SFs into iPSCs (Fig 1B) using a safe mRNA-based reprogramming method , and differentiated them into iCMCs, which gained beating on day 7. We found that hPGP1-iCMCs (Fig 1C) had an irregular contractile function by Particle Image Velocimetry Analysis and decreased cardiac-specific gene and protein expressions by qRT-PCR and Western Blot. Conclusions: We successfully generated iCMCs from a progeria patient carrying LMNA variant c.1824C>T. These iCMCs were found to be functionally and structurally defective when compared to normal iCMCs. Our in vitro model will help elucidate the role of Lamin A and the cardio-pathologic mechanisms associated with progeria.

Pullout testing and Particle Image Velocimetry (PIV) analysis of geogrid reinforcement embedded in granular drainage layers

The paper investigates the feasibility of using fine-grained soil as backfill material of geosynthetic-reinforced walls and slopes, through a laboratory study on pullout behavior of geogrids in granular layers. A series of pullout tests was carried out on an HDPE uniaxial geogrid in thin sand and gravel layers that were embedded in clay specimens.Aside from different soil arrangements, the influences of moisture content and overburden pressure on the geogrid pullout behavior is assessed and discussed. The tests were carried out at four different gravimetric water contents (GWC) on the dry and wet sides of the clay optimum moisture content (OMC), and overburden pressure values within the range σv = 25–100 kPa. Particle Image Velocimetry (PIV) was used to capture digital images during the tests, which were processed to help with the interpretation and improved understanding of the soil-geogrid interactions at different GWC values. Results show that embedding geogrid reinforcement in layers of sand or gravel can significantly increase the pullout resistance in an otherwise moist clay backfill, and this improved pullout efficiency is greater at higher overburden pressures. The improvement in pullout capacity was observed in clay specimens compacted at both the dry and wet sides of the OMC.

Super-Resolution Study Of Wall Sheer Stress In Cerebral Aneurysm With AI PIV

Aneurysms are one of the most common unexplored causes of death. There are many studies conducted by scientists around the world on this issue. The main problem raised is the cause of aneurysms. Here, the division includes several branches, i.e. genetic conditions, lifestyle, eg. smoking, and finally hemodynamic factors of blood flow. It is well known that the aneurysm is formed and ruptured at the site of high wall shear stress (WSS). This paper presents the comparison of results of CFD blood flow simulations with experimental values obtained with the Particle Image Velocimetry (PIV) method in a 3D model of a cerebral aneurysm. A 3D model of a cerebral aneurysm was developed using specific patient CT data. The hemodynamical parameters were analysed for different flow rates in a 3D model under pulsatile flow conditions. The CFD simulation was done using Ansys CFX software. Results of the simulation were validated with the experimental PIV method. Two different PIV methods were employed: traditional PIV based on cross-correlation (CC) algorithms and Artificial Intelligence PIV (AI PIV) based on Deep Learning and Convolutional Neural Networks. The obtained results showed a better correlation between CFD simulation and types of PIV analysis for data of AI PIV, which allows for a much higher spatial resolution of the resulting velocity field. Analysis of the results was promising and showed that AI PIV could be used to get accurate results.

PIV analysis of confined multiple jets impinging on a step surface

Forced convection by submerged multiple jet impingement for cooling applications is widely implemented in several industrial sectors. However, the complexity of the flow makes this process difficult to control. Therefore, it is important to conduct an in-depth study in order to characterize the flow field and this is possible through Particle Image Velocimetry (PIV) technique. PIV allows the measurement of the velocity field and information regarding flow vorticity and turbulence intensity can be obtained. To conduct the PIV measurements, an experimental setup was specially built to analyze the flow dynamics of multiple air jets impinging on a surface with a step. In PIV, the selection of the most appropriate tracer particles is crucial to ensure accurate measurements. In that sense, this work comprises an analysis of different seeding particles produced by a Concept Smoke Aerotech system. The measurement region consists of an array of multiple air jets spaced 3 D (jet diameters) between them according to a staggered configuration. The jets are confined and a distance between the nozzle plate and the target surface of 2 D is applied. The central, back, and front rows are analyzed in order to determine the effect of the jet’s interactions on the velocity fields and heat transfer. The results show that the complexity of the flow is increased by the implementation of a non-flat surface. The step induces a strong flow reversal that affects the jet flow development over the surface. Moreover, the measured data highlights the complex interactions between jets and confirm that PIV is able to capture the large-scale structures induced in the vicinity of the target plate, as well as the strong fountain flows generated between the adjacent jets. Furthermore, the results show that the combination of PIV and heat flux sensors is appropriate to characterize the jet’s flow dynamics and the heat transfer of multiple jets impinging on a surface, providing relevant insights for several engineering applications. This study underlines the advantages of the PIV system for a detailed characterization of a multiple jet impingement flow and the importance of a proper definition of the experimental condition to ensure the accuracy of the measurements.

High-frame-rate contrast-enhanced ultrasound particle image velocimetry in patients with a stented superficial femoral artery: a feasibility study

BackgroundLocal blood flow affects vascular disease and outcomes of endovascular treatment, but quantifying it is challenging, especially inside stents. We assessed the feasibility of blood flow quantification in native and stented femoral arteries, using high-frame-rate (HFR) contrast-enhanced ultrasound (CEUS) particle image velocimetry (PIV), also known as echoPIV.MethodsTwenty-one patients with peripheral arterial disease, recently treated with a stent in the femoral artery, were included. HFR CEUS measurements were performed in the native femoral artery and at the inflow and outflow of the stent. Two-dimensional blood flow was quantified through PIV analysis. EchoPIV recordings were visually assessed by five observers and categorised as optimal, partial, or unfeasible. To evaluate image quality and tracking performance, contrast-to-tissue ratio (CTR) and vector correlation were calculated, respectively.ResultsFifty-eight locations were measured and blood flow quantification was established in 49 of them (84%). Results were optimal for 17/58 recordings (29%) and partial for 32 recordings (55%) due to loss of correlation (5/32; 16%), short vessel segment (8/32; 25%), loss of contrast (14/32; 44%), and/or shadows (18/32; 56%). In the remaining 9/58 measurements (16%) no meaningful flow information was visualised. Overall, CTR and vector correlation were lower during diastole. CTR and vector correlation were not different between stented and native vessel segments, except for a higher native CTR at the inflow during systole (p = 0.037).ConclusionsBlood flow quantification is feasible in untreated and stented femoral arteries using echoPIV. Limitations remain, however, none of them related to the presence of the stent.Trial registrationClinicalTrials.gov, NCT04934501 (retrospectively registered).

An extraction method of fish vector field for marine cage culture based on UAV vision

To obtain the motion state of a school of fish in marine cage culture and improve the automatic detection capability for large areas of marine culture, this paper proposes a fish-motion vector-field extraction method for marine cage culture, which primarily comprises cage region extraction and motion vector calculation. The proposed method uses an unmanned aerial vehicle (UAV) as the carrier, and the interference of marine environment is fully considered. First, blurred images are discarded, and the culture area is obtained by a holistically-nested edge detection (HED) network. Second, the validity of the current frame is determined by the local binary patterns (LBPs) of the feature image. Third, the images are transformed, and the vector-field information of fish swarm is obtained using the particle image velocimetry (PIV) analysis method. This study integrates traditional image analysis and deep network technology while also fully considering the image distortion caused by UAV flight attitude changes in the actual detection process. Finally, images of Takifugu rubripe net cages were used to verify the method. The results show that the proposed method has strong practicability and applicability.

A PIV-Based Algorithm for Simultaneous Determination of Multiple Velocity Fields from Stratified Crossflows in Single Field of View

This study presents a new imaging-based algorithm for simultaneously determining multiple velocity fields from stratified crossflows optically captured in a single field of view. The concept implements an additional automatic peak finding scheme into the conventional particle image velocimetry (PIV) analysis procedure, identifying multiple prominent peak cross-correlation coefficients corresponding to the flows in various directions. To examine the validity, synthetic particle images generated by computer visions and image data acquired by PIV measurements are employed in the validation study. With both root-mean-square errors (RMSEs) in magnitude and direction being found to be temporally random, the validation results suggest that the performance of the new algorithm is ideal for steady or quasi-steady flows. This implies that the new algorithm may also work well for the flows repeatable with identical initial and boundary conditions. For transient flows, more valuable data can be obtained with the new algorithm, particularly in large-scale experiments or field measurements. Moreover, tests on synthetic images show that the RMSE in magnitude decays exponentially with increasing tracking particle density, and a density of 30% is found to be the lowest for the minimum RMSE in magnitude. Discussions on the error reduction, limitations of the new algorithm, suggestions for applications, and guidance on spurious vector removal are given as well.

Effects of groove angle and pattern on CFRP-to-concrete bond behavior of EBROG joints: Comparison of diagonal with longitudinal and transverse grooves

Recently, the novel method of externally bonded reinforcement on grooves (EBROG) has been introduced as an alternative to the conventional externally bonded reinforcement (EBR) technique to attach the fiber-reinforced polymer (FRP) sheets to concrete. Although extensive research has been carried out on the EBROG joints with longitudinal and transverse grooves, no single study exists to investigate the diagonal grooves with different angles and patterns. Besides, the function of longitudinal, transverse, and diagonal grooves with similar conditions has not been yet compared. This paper is the first attempt to compare the bond strength, effective bond length, and bond behavior (i.e., load-carrying mechanism and strain field distribution) of EBROG specimens with longitudinal (zero degrees), transverse (90 degrees), and diagonal grooves (21, 37, 45, and 63 degrees). Twenty specimens were strengthened with the EBROG method through different groove angles and patterns, and two specimens were strengthened with the EBR method. The total grooves’ length was kept almost the same in all the strengthened specimens. The specimens were then subjected to a single-lap shear test. From the results, the optimum groove angles were found to be zero (longitudinal groove) and 90 degrees (transverse groove); e.g., compared to EBR, in the specimens with 30 mm groove spacing, the longitudinal and transverse grooves increased the bond strength up to 84.5% and 89.7%, while a 52.6% increase was observed for diagonal grooves with 45-degree groove angle. The particle image velocimetry (PIV) analysis revealed that the specimens with longitudinal and transverse grooves had greater effective bond lengths compared to those with diagonal grooves. PIV results showed that although diagonal grooves in both zigzag and parallel patterns yielded almost the same bond resistance, they led to different bond behavior.

Monitoring Flexure Behavior of Compacted Clay Beam Using High-Resolution Distributed Fiber Optic Strain Sensors

Abstract Understanding the mechanical characteristics of clayey soil is critical to estimate the stability of clay-related geotechnical engineering works. However, the distributed information of the internal deformation of clay is hard to capture through traditional methods. In this paper, a set of four-point bending tests were performed on a compacted clay beam instrumented with fiber optic strain sensors to investigate the flexure and cracking behaviors. The optical frequency domain reflectometry technique with high spatial resolution and precision was employed to establish a distributed strain sensing (DSS) system in this study. The results show that the DSS system exhibits a high accuracy in the collection of the clay deformation in terms of compression, tension, and cracking. The comparison of the internal strain profiles with the observation of particle image velocimetry analysis system verifies the feasibility of fiber optic sensing technology in the quantitative assessment of clay deformation. The performance of fiber optic sensors in the rebound deformation and creep deformation monitoring was preliminarily issued in the study. In addition, the progressive failure on the fiber–soil interface was analytically studied to evaluate the deformation compatibility between the fiber and surrounding clayed soil. The conclusions drawn in this paper can help to guide the state interpretation of clayey soil instrumented with fiber optic sensors.

Vacuum-induced lateral deformation around a vertical drain in dredged slurry

The horizontal strain in the vacuum preloading/dewatering of dredged slurry is significant to the apparent clogging effect and estimation of surface settlement around a drain; however, it has seldom been investigated in previous studies. In this study, a vacuum consolidation model test assisted by particle image velocimetry (PIV) technology was conducted. The displacement vector field was obtained through PIV analysis and image processing; it was used to visually observe the deformation features around a drain. Based on the displacement field, the vertical/horizontal strains at varied radial distances were calculated to explain the ‘soil pile’ and apparent clogging effect. From the strain distribution with radial distances, a significant lateral compression zone near the drain and an extension zone at farther areas were confirmed. Furthermore, a simple explicit model was established to evaluate the horizontal strain within a prefabricated vertical drain unit cell considering a horizontal attenuated vacuum and compression/extension zone. Finally, this method was applied to predict the horizontal displacement in the model test. The results showed that the proposed method can estimate the lateral displacement of soft clay slurry fairly well.

Insight Into Granular Flow Dynamics Relying on Basal Stress Measurements: From Experimental Flume Tests

AbstractKnowledge on the interactions between granular flows and their boundaries is essential for understanding granular flow dynamics. In this study, a series of experiments designed with different conditions were conducted using a flume configuration to investigate the granular flow behaviors and dynamics by particle image velocimetry analysis and basal normal stress measurements. The results demonstrate that the velocity profiles and depth‐averaged shear rates of the granular flows significantly vary with grain size, but display insignificant changes with flow volume. For granular flows with higher content of coarse particles, high magnitude fluctuating stresses with values much greater than the mean normal stress are observed. The particle agitation of the granular flow, which is quantified by the normalized standard deviation of the fluctuating stress from the mean normal stress, exhibits a positive correlation and a negative correlation with the solid inertial stress and the equivalent friction coefficient, respectively. This indicates that the enhanced particle agitation related to the high magnitude fluctuating stress should contribute to the mobility of the granular flows. The generation of the high magnitude fluctuating stress is attributed to the high‐frequency and intensive particle collisions in grain‐scale, which is mainly determined by grain size. In this study, the increase of flow volume mostly resulted in an increase in the fluctuating stress related to the mean normal stress, which exhibits a minor effect on particle agitation and has no contribution toward the mobility of the granular flows.

Classroom demonstration of a stagnation flow using cell phone-captured particle image velocimetry data

Courses in fluid mechanics and aerodynamics often require lengthy and involved mathematical derivations. However, these subjects are also associated with visually appealing flow features. In an effort to provide students with a full appreciation for fluid mechanics, it is desirable to not only provide a theoretical background, but also perform some visual demonstrations; this can be achieved through quantitative flow visualization demonstration. The cost of research-grade equipment is prohibitive for a teaching college, especially if only used for classroom demonstration. This article describes a Particle Image Velocimetry (PIV) demonstration of flow around a vertical plate using widely available cell phone cameras, reducing the cost of the required equipment. The velocity field calculated using PIV analysis was compared to a velocity field predicted using potential flow theory. The two showed an agreement of about 30% – a sufficient accuracy for an in-classroom demonstration. The learning effectiveness of this demonstration was evaluated using course evaluations and an end-of-semester survey. Overall, students expressed their appreciation for added experimental work and visualization to the course curriculum.

Evaluation of square slender RC columns subjected to eccentric loading strengthened with longitudinal FRP sheets based on PIV analysis

In this study, the behavior of square slender reinforced concrete (RC) columns strengthened with carbon fiber-reinforced polymer (CFRP) sheets was investigated. The externally bonded reinforcement on grooves (EBROG) method as a new technique was employed to strengthen the specimens compared to the externally bonded reinforcement (EBR) method as the conventional strengthening technique. Twelve small-scale slender square RC columns (i.e., 125 × 125 × 900 mm) with a slenderness ratio of 25 were loaded under eccentricity-to-cross-section ratios (e/h) of 0, 0.24, 0.48, and 0.72. The results showed the EBROG's superiority over EBR in load-carrying capacity enhancement of the strengthened RC column specimens in various eccentricities; i.e., the loading enhancements were 10.6 to 99.3% for the EBROG specimens and 1.2 to 41.7% for the EBR specimens at varying eccentricities of 0 to 90 mm, compared to those of un-strengthened specimens. Furthermore, the moment capacity enhancement of the EBROG specimens was higher than that of the EBR columns; i.e., it was 100.0% for the EBROG specimens and 42.2% for EBR specimens in the eccentricity of 90 mm, compared with the un-strengthened specimen. Using particle image velocimetry (PIV) analyses, the results of flexural stiffness, strain distribution, ductility, and energy absorption were presented and discussed. Results revealed that by increasing the eccentricity, flexural stiffness decreases; this reduction was more intense for EBR specimens (42%) than the EBROG specimen (36%). An analytical procedure was conducted to compare the experimental and theoretical results. The analysis demonstrated good agreement between the results and the superiority of the EBROG method over the EBR.

Glycopolymer Engineering of the Cell Surface Changes the Single Cell Migratory Direction and Inhibits the Collective Migration of Cancer Cells.

Cancer cell migration is one of the most important processes in cancer metastasis. Metastasis is the major cause of death from most solid tumors; therefore, suppressing cancer cell migration is an important means of reducing cancer mortality. Cell surface engineering can alter the interactions between cells and their microenvironment, thereby offering an effective method of controlling the migration of the cells. This paper reports that modification of the mouse melanoma (B16) cancer cell surface with glycopolymers affects the migration of the cells. Changes in cell morphology, migratory trajectories, and velocity were investigated by time-lapse cell tracking. The data showed that the migration direction is altered and diffusion slows down for modified B16 cells compared to unmodified B16 cells. When modified and unmodified B16 cells were mixed, wound-healing experiments and particle image velocimetry (PIV) analysis showed that the collective migration of unmodified B16 cells was suppressed because of vortexlike motions induced by the modified cells. The work demonstrates the important role of surface properties/modification in cancer cell migration, thereby providing new insights relative to the treatment of cancer metastasis.

Spatial Breach Analysis due to Overtopping Flow Depending on the Degree of Compaction for Noncohesive Embankments

This study aimed to an experiment to analyze the spatial levee breach mechanisms due to overtopping according to the degree of compaction. A levee experiment was performed using four different degree of compaction implemented by adjusting the levee compaction thickness and number of compactions, and the effects of the degree of compaction on levee breaching were observed. Under the low degree of compaction, the scale of the levee breach over time was relatively large, and the breach discharge was also significant. This study also observed the change in velocity of the levee crest area through Large Scale Particle Image Velocimetry (LSPIV) analysis of the velocity field at each levee breach stage; in particular, the location where the maximum velocity occurred in the crest area differed according to the degree of compaction. The relationship between the degree of compaction and peak breach discharge shown in experimental results suggests the degree of compaction can directly affect the breach of the levee and the flooding velocity at the low-land area. The clear correlations between the degree of compaction and breach discharge and breach size over time presented in this study can provide detailed information for the design standards and maintenance of the levee.

QuickPIV: Efficient 3D particle image velocimetry software applied to quantifying cellular migration during embryogenesis

BackgroundThe technical development of imaging techniques in life sciences has enabled the three-dimensional recording of living samples at increasing temporal resolutions. Dynamic 3D data sets of developing organisms allow for time-resolved quantitative analyses of morphogenetic changes in three dimensions, but require efficient and automatable analysis pipelines to tackle the resulting Terabytes of image data. Particle image velocimetry (PIV) is a robust and segmentation-free technique that is suitable for quantifying collective cellular migration on data sets with different labeling schemes. This paper presents the implementation of an efficient 3D PIV package using the Julia programming language—quickPIV. Our software is focused on optimizing CPU performance and ensuring the robustness of the PIV analyses on biological data.ResultsQuickPIV is three times faster than the Python implementation hosted in openPIV, both in 2D and 3D. Our software is also faster than the fastest 2D PIV package in openPIV, written in C++. The accuracy evaluation of our software on synthetic data agrees with the expected accuracies described in the literature. Additionally, by applying quickPIV to three data sets of the embryogenesis of Tribolium castaneum, we obtained vector fields that recapitulate the migration movements of gastrulation, both in nuclear and actin-labeled embryos. We show normalized squared error cross-correlation to be especially accurate in detecting translations in non-segmentable biological image data.ConclusionsThe presented software addresses the need for a fast and open-source 3D PIV package in biological research. Currently, quickPIV offers efficient 2D and 3D PIV analyses featuring zero-normalized and normalized squared error cross-correlations, sub-pixel/voxel approximation, and multi-pass. Post-processing options include filtering and averaging of the resulting vector fields, extraction of velocity, divergence and collectiveness maps, simulation of pseudo-trajectories, and unit conversion. In addition, our software includes functions to visualize the 3D vector fields in Paraview.

3D viscoelastic drag forces contribute to cell shape changes during organogenesis in the zebrafish embryo.

The left-right organizer in zebrafish embryos, Kupffer's Vesicle (KV), is a simple organ that undergoes programmed asymmetric cell shape changes that are necessary to establish the left-right axis of the embryo. We use simulations and experiments to investigate whether 3D mechanical drag forces generated by the posteriorly-directed motion of the KV through the tailbud tissue are sufficient to drive such shape changes. We develop a fully 3D vertex-like (Voronoi) model for the tissue architecture, and demonstrate that the tissue can generate drag forces and drive cell shape changes. Furthermore, we find that tailbud tissue presents a shear-thinning, viscoelastic behavior consistent with those observed in published experiments. We then perform live imaging experiments and particle image velocimetry analysis to quantify the precise tissue velocity gradients around KV as a function of developmental time. We observe robust velocity gradients around the KV, indicating that mechanical drag forces must be exerted on the KV by the tailbud tissue. We demonstrate that experimentally observed velocity fields are consistent with the viscoelastic response seen in simulations. This work also suggests that 3D viscoelastic drag forces could be a generic mechanism for cell shape change in other biological processes.

Effects of the Installation Method, Loading Condition, and Failure Mechanism on the Behavior of Suction Piles under Monotonic Horizontal Loading

A suction pile is a promising option when floating offshore structures are deployed at deep and distant locations. A suction pile is typically used for the foundation system of a mooring system subjected to horizontal loading with a load inclination. In this study, the effects of installation method, loading position, and load inclination on the behavior of a suction pile under monotonic horizontal loading were evaluated via large-scale soil chamber testing. A series of horizontal load tests were performed by varying the loading position at pile embedded lengths of 1/4, 1/2, 2/3, and 3/4. A horizontal load test with a load inclination of 20° was conducted and compared with that of a load inclination of 0°. The failure mechanism of the suction piles under monotonic horizontal loading was assessed via particle image velocimetry (PIV) analysis. The movement of the suction pile during monotonic horizontal loading was elucidated in terms of the horizontal displacement, vertical displacement, and rotation angle. The results of this study show apparent differences between jacking and suction-installed piles and piles under different loading conditions. The PIV analysis shows that the rotational behavior under monotonic horizontal loading can be a critical point to affect the horizontal resistance of the suction pile.

Post-Processing Deflectometry Grid Images Using Particle Image Velocimetry Analysis

AbstractDeflectometry is a full-field optical technique for surface slope measurement based on recording the deformation of a grid image. A hybrid method is explored in which the grid images from a deflectometry measurement are processed using a particle image velocimetry analysis tool. The hybrid approach is compared to a common phase shifting algorithm for grid images based on a windowed discrete Fourier transform. The resulting slope maps compare well with those identified using the spatial phase shifting procedure. While the traditional phase shifting method has a tuning requirement that limits the optical setup to configurations that produce an integer number of pixels per grid period in the image, the use of particle image velocimetry analysis omits this calibration step. The applicability of an existing turnkey tool to perform full-field vibration imaging using deflectometry can benefit to research concerning mechanical vibration and related experimental methods.

Overlimiting convection at a heterogeneous cation-exchange membrane studied by particle image velocimetry

Electroconvection and gravitational convection are recognized as the primary mechanisms driving overlimiting currents in ion-exchange systems. Here, we use particle image velocimetry (PIV) to characterize the convection on a small piece of a commercially available heterogeneous cation-exchange membrane. We perform chronoamperometric measurements under various experimental conditions and simultaneously record the developed convection at the membrane-electrolyte solution interface using tracking particles. The convection is observed independently in horizontal and vertical planes, capturing flow fields pertinent to electroconvection and gravitational convection. PIV analysis computes velocity vector fields we employ to calculate the volumetric flow rate through a virtual semi-cylindrical wall around the membrane. The volumetric flow rate represents a way how to quantify the intensity of electroconvection. The electroconvection recorded on the horizontal plane manifests itself as a local short-range chaotic whirring localized at the membrane surface superimposed by two long-range counter-current vortices. The volumetric flow rate associated with the two counter-current vortices almost linearly increases with voltage and decreases with increasing concentration. The stagnant points of the vortices localize from 100 to 450 μm away from the membrane. The convection observed on the vertical plane occurs as a result of electroconvection and gravitational convection. We show that gravitational convection eventually dominates and produces an upward-directed intensive flow with similar values of characteristic velocities as the electroconvection. The development of the gravitational convections is approximately one order of magnitude slower (on the order of seconds) than that of electroconvection (on the order of hundreds of milliseconds).