Flow Profile Measurements Research Articles

Extension Of Spatial Filtering Technique Using Kalman Filters For Real-Time Pipe Flow Profile Measurements

Spatial filtering is used for real-time velocity measurement due to its computational efficiency. However, this method can be noisy in real measurement environments, requiring the averaging of a substantial number of measurements to achieve reliable results, which compromises temporal resolution. This study proposes enhancing the spatial filtering algorithm by implementing Kalman filtering for pipe flow profile measurements. Kalman filtering is expected to mitigate the noise issue more effectively than traditional methods like low-pass filtering while maintaining or improving the temporal resolution of measurements.

Perturbed Ion Temperature and Toroidal Flow Profile Measurements in Rotating Neoclassical Tearing Mode Magnetic Islands.

The perturbed ion temperature and toroidal flow were measured in rotating neoclassical tearing modes (NTM) in a tokamak for the first time. These toroidally and radially resolved profiles were obtained by impurity ion spectroscopy in a 2,1 NTM in DIII-D. In agreement with drift-kinetic simulations, the electron temperature profile is flat, while the ion temperature gradient is restored across the magnetic island O point in the presence of fast ions; the perturbed flow has minima in the O points and maxima at the X points. These measurements provide the first confirmation of the theoretically expected ion temperature and flow response to a magnetic island needed to predict the NTM onset threshold scaling for ITER and other future tokamaks.

Theories of complicated identifications exchange

The main objective of this study is to determine the pressure derivatives diagnoses for the infinite-conductivity horizontal well flow regimes identification which are not well studied so far in literature. The pressure derivatives diagnoses for the uniform-flux horizontal well flow regimes identification are fully studied in literature and presented here for comparison purposes only. The horizontal well flow regimes: early-radial, early-linear, late-radial, late-linear, and pseudo-steady state (PSS) are being identified. The identifications of flow regimes which have characteristic trends on log-log graph of pressure derivatives versus time represent unique technique in reservoir characterization. Five pressure derivatives are studied in detail: primary pressure derivative (PPD) (i.e., PPD=∂PD/∂tDA), Slope of PPD, PPD ×tDA, Bourdet derivative (i.e., tDA × PPD), and Slope of Bourdet derivative. For the first time, the pressure derivatives have been computed at high-resolution to diagnose the five infinite-conductivity horizontal well flow regimes identifications (i.e., the wellbore is discretized into twenty thousand of segments). In field application, synthetic pressure drawdown test data for infinite-conductivity horizontal well are analyzed by using type-curve matching technique.The novelties in this study are the following:1.The identifications of infinite-conductivity early-radial and early-linear flow regimes by Slope of Bourdet derivative are equal to −0.5 and 0 respectively which are different to their uniform-flux counterparts 0 and 0.5 respectively. Therefore, the pressure derivatives diagnoses are unique for a certain wellbore condition and there is a complicated identifications exchange between uniform-flux and infinite-conductivity flow regimes. The identification of infinite-conductivity early-radial flow regime is used for uniform-flux spherical flow regime and vice versa, and the identification of infinite-conductivity early-linear flow regime is used for uniform-flux early-radial and late-radial-flow regimes and vice versa.2.Theories of developing infinite-conductivity early-radial flow regime by multi aligned and merged uniform-flux spherical flow regimes and developing infinite-conductivity early-linear flow regime by multi aligned uniform-flux early-radial flow regimes are presented. The new theories prove the existence of the complex identifications exchange between uniform-flux and infinite-conductivity flow regimes.3.Without type-curve matching technique, downhole flow or pressure profile measurement, or presence of uniform-flux early-linear flow regime, or determination of mt at late-radial, late-linear, or PSS flow regime are crucial to distinguish if the wellbore is under uniform-flux or infinite-conductivity condition for correct horizontal well test analysis, mt = segments number of the half-length wellbore.4.At infinite-conductivity late-linear flow regime, qD distribution over the wellbore is uniform for any well and reservoir configuration as at infinite-conductivity PSS flow regime, qD = dimensionless inflow rate.

Self-organized canals enable long-range directed material transport in bacterial communities.

Long-range material transport is essential to maintain the physiological functions of multicellular organisms such as animals and plants. By contrast, material transport in bacteria is often short-ranged and limited by diffusion. Here, we report a unique form of actively regulated long-range directed material transport in structured bacterial communities. Using Pseudomonas aeruginosa colonies as a model system, we discover that a large-scale and temporally evolving open-channel system spontaneously develops in the colony via shear-induced banding. Fluid flows in the open channels support high-speed (up to 450 µm/s) transport of cells and outer membrane vesicles over centimeters, and help to eradicate colonies of a competing species Staphylococcus aureus. The open channels are reminiscent of human-made canals for cargo transport, and the channel flows are driven by interfacial tension mediated by cell-secreted biosurfactants. The spatial-temporal dynamics of fluid flows in the open channels are qualitatively described by flow profile measurement and mathematical modeling. Our findings demonstrate that mechanochemical coupling between interfacial force and biosurfactant kinetics can coordinate large-scale material transport in primitive life forms, suggesting a new principle to engineer self-organized microbial communities.

NO-HYPE: a novel hydrodynamic phantom for the evaluation of MRI flow measurements

Accurate and reproducible measurement of blood flow profile is very important in many clinical investigations for diagnosing cardiovascular disorders. Given that many factors could affect human circulation, and several parameters must be set to properly evaluate blood flows with phase-contrast techniques, we developed an MRI-compatible hydrodynamic phantom to simulate different physiological blood flows. The phantom included a programmable hydraulic pump connected to a series of pipes immersed in a solution mimicking human soft tissues, with a blood-mimicking fluid flowing in the pipes. The pump is able to shape and control the flow by driving a piston through a dedicated software. Periodic waveforms are used as input to the pump to move the fluid into the pipes, with synchronization of the MRI sequences to the flow waveforms. A dedicated software is used to extract and analyze flow data from magnitude and phase images. The match between the nominal and the measured flows was assessed, and the scope of phantom variables useful for a reliable calibration of an MRI system was accordingly defined. Results showed that the NO-HYPE phantom is a valuable tool for the assessment of MRI scanners and sequence design for the MR evaluation of blood flows.Graphical abstractOverview of the NOvel HYdrodynamic Phantom for the Evaluation of MRI flow measurements (NO-HYPE). Left: internal of the CompuFlow 1000 MR pump unit. Right: Setting of the NO-HYPE before a MRI acquisition session. Soft tissue mimicking material is hosted in the central part of the phantom (light blue chamber). Glass pipes pass through the chamber carrying the blood mimicking fluid.

Resting coronary blood flow velocity profile predicts coronary flow reserve in HFpEF

Abstract Background Coronary microvascular disease (CMD) is prevalent in patients with heart failure with preserved ejection fraction (HFpEF). CMD can be assessed by coronary flow reserve (CFR) using transthoracic echocardiography (TTE). We hypothesised that the coronary Doppler flow profile in LAD at rest could reveal information about the downstream resistance in the vessel, where increased resistance is a sign of CMD. Purpose We aimed to measure features of the acceleration and deceleration of the LAD Doppler flow profile to investigate association with coronary and cardiac function. Methods CFR was assessed in 202 patients by TTE in the PROMIS-HFpEF-study. Detailed flow profile measurements were possible in 169 patients (84%) who constituted the study population. The coronary Doppler flow profiles were analysed with respect to acceleration time (corAT) and slope (corAS) and deceleration pressure half time (corPHT) (figure 1). Results The average age was 75±9 years and 55% were female. Atrial fibrillation (AF) was present in 53% and 62% were current or previous smokers. There was no significant difference in gender, age, BMI, blood pressure or heart rate in the CMD vs non-CMD group, but AF as well as a history of smoking was more prevalent in the CMD group, p=0.022 and 0.003 respectively. Further, there were no significant differences in neither corAT nor corAS between the two groups. However, patients with CMD had shorter corPHT of 268±64 ms compared to 298±67 ms, p=0.01. A longer corPHT was associated with increased TAPSE (R=0.205, p=0.007) and higher CFR (R=0.231, p=0.002). In a multivariable analysis adjusted for age, sex, BMI, SBP, reactive hyperemia index, HR, AF, diabetes, CVD, smoking, LVM and study site*, corPHT independently predicted CFR (table 1, p=0.016). Conclusion Short pressure half time, indicating a steep deceleration of the coronary Doppler signal at rest, may provide useful information for prediction of CFR determined by transthoracic ultrasound by reflecting the increased resistance in the coronary microvasculature associated with CMD. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Sahlgrenska University Hospital, Sponsor AstraZeneca

Simulation and measurement of rarefied gas flow and neutral density profiles through a large multiaperture multigrid negative ion accelerator

In large multi-aperture, multi-grid negative-ion accelerator for fusion application, the background gas density in the electrostatic accelerator causes a loss of negative-ion current and the formation of dangerous stray particles. In addition, to sustain in dynamic equilibrium a sufficient gas pressure in the plasma ion-source, a very large pumping speed is typically necessary. This paper presents and compare simulations and measurements of gas flows and background pressure profiles, through the electrostatic accelerator of the SPIDER beam source, the full-size prototype source of the ITER neutral beam injectors. The gas pressure profiles through the ion accelerator were measured by multiple movable capacitive pressure gauges, mapping the uniformity of the profiles along nine beamlets at three different filling pressures. The gas flow simulations in molecular flow regime were performed with a large-scale view-factor model, and with a single-aperture periodic test particle Monte Carlo model. The models reproduced the measured pressure profiles but additionally, provided also the profiles of local gas density. The gas conductance and the profiles calculated with the full-scale gas flow model correctly reproduce the measured profiles, and the transversal non-uniformities over the 1.6 m × 0.6 m cross section. The calculated gas density profile is also verified by comparing the two different numerical approaches. The gas flow model validated at room temperature can be used to simulate the pressure profile during operation, in presence of gas heating and dissociation by the source plasma.

Asymmetry of parallel flow on the Large Helical Device

An asymmetric parallel return flow, which modifies the parallel component of the flow, is expected to meet the zero divergence of the flow on a flux surface based on the common neoclassical theory for torus plasma. The full flow structure is measured by charge exchange spectroscopy on the Large Helical Device. Inboard/outboard asymmetry of the parallel flow is observed according to the full flow profile measurement. Flow asymmetry is considered to be induced by the Pfirsch–Schlüter flow closely associated with the radial electric field. A linear relationship between the integrated flow asymmetry and the electric potential difference is obtained in different magnetic fields and configurations. A model based upon the incompressibility of the flow is applied to acquire a geometric factor hB, which only connects to the magnetic configuration from the experiment. The asymmetric component of the parallel flow measured is compared with the asymmetric component of parallel flow calculated in the incompressibility conditions of flow on the magnetic flux surface. The measured asymmetric flow is consistent with the calculation in plasma with a small toroidal torque input in the inward shifted configuration. However, the measured asymmetric flow is significantly smaller than that calculated for plasma with a large toroidal torque or in the outward shifted configuration. One possible explanation for this variation could be radial transport due to anomalous perpendicular viscosity as well as strongly poloidally asymmetric radial flow.

A magnetic resonance imaging-compatible small animal model under extracorporeal circulation.

The impact of different extracorporeal circulation (ECC) scenarios on arterial blood flow profiles has not yet been revealed. To allow for exact measurements, magnetic resonance imaging (MRI) during ECC is required. Therefore, the present study addressed the feasibility of a high-resolution MRI-compatible animal model of ECC. For usage in New Zealand White rabbits, we developed an ECC device, the tubes of which were long enough to eliminate impacts of the magnetic field on the blood pump and heart-lung control machine. The miniaturized ECC system via thoracic access comprised an infant oxygenator, a pulsatile centrifugal pump, 1/8″ tubes, a 10-Fr aortic cannula and a 12-Fr venous cannula for vacuum-assisted drainage. This miniaturized ECC system has very low priming volume (230-255 ml) to reduce the system-inherent haemodilution to 50%. Consequently, haemoglobin rates remained high enough to guarantee adequate oxygenation (arterial pressure of oxygen >200 mmHg). Optimized venous drainage by an additionally inserted pulmonary artery vent catheter resulted in sufficient blood flow (31.6-65.8 ml/min/kg) that was maintained for 60 min with pulsatility. The current study demonstrates the feasibility of MRI-compatible ECC in rabbits, and this model allows for real-time blood flow profile measurements during different ECC scenarios in future projects.

Electrical Resistance Tomography for Visualization of Moving Objects Using a Spatiotemporal Total Variation Regularization Algorithm.

Electrical resistance tomography (ERT) has been considered as a data collection and image reconstruction method in many multi-phase flow application areas due to its advantages of high speed, low cost and being non-invasive. In order to improve the quality of the reconstructed images, the Total Variation algorithm attracts abundant attention due to its ability to solve large piecewise and discontinuous conductivity distributions. In industrial processing tomography (IPT), techniques such as ERT have been used to extract important flow measurement information. For a moving object inside a pipe, a velocity profile can be calculated from the cross correlation between signals generated from ERT sensors. Many previous studies have used two sets of 2D ERT measurements based on pixel-pixel cross correlation, which requires two ERT systems. In this paper, a method for carrying out flow velocity measurement using a single ERT system is proposed. A novel spatiotemporal total variation regularization approach is utilised to exploit sparsity both in space and time in 4D, and a voxel-voxel cross correlation method is adopted for measurement of flow profile. Result shows that the velocity profile can be calculated with a single ERT system and that the volume fraction and movement can be monitored using the proposed method. Both semi-dynamic experimental and static simulation studies verify the suitability of the proposed method. For in plane velocity profile, a 3D image based on temporal 2D images produces velocity profile with accuracy of less than 1% error and a 4D image for 3D velocity profiling shows an error of 4%.

Rheological properties of washed and unwashed tilapia (Oreochromis mossambicus) fish meat: effect of sucrose and sorbitol.

In the present study, the dynamic viscoelastic behavior (DVB) and flow behavior of fresh tilapia (Oreochromis mossambicus) meat containing cryoprotectants were evaluated with and without water washing. The DVB profile of washed meat with 4% sucrose and sorbitol indicated the maximum structure buildup reaction up to 56.8°C; thereafter, hydrophobic interactions leading to decreased gelation were suppressed. In both the samples, there was no clear indication of the sol-gel transition temperature. In flow-profile measurements, the presence of cryoprotectants gave rise to the minimum thixotropic area, indicating a low level of impairment in structure. The shear-stress sweep of water-washed tilapia proteins added with cryoprotectants did not reveal significant changes at 28 and 40°C. In texture-profile analysis, the hardness values were lower in fresh meat than cooked meat. The findings of this study will be helpful in the formulation and design of various mince-based products and in determining the appropriate use of cryoprotectants and water washing in the processing of minced meat.

Velocity measurement by coherent x-ray heterodyning.

We present a small-angle coherent x-ray scattering technique used for measuring flow velocities in slow moving materials. The technique is an extension of X-ray Photon Correlation Spectroscopy (XPCS): It involves mixing the scattering from moving tracer particles with a static reference that heterodynes the signal. This acts to elongate temporal effects caused by flow in homodyne measurements, allowing for a more robust measurement of flow properties. Using coherent x-ray heterodyning, velocities ranging from 0.1 to 10 μm/s were measured for a viscous fluid pushed through a rectangular channel. We describe experimental protocols and theory for making these Poiseuille flow profile measurements and also develop the relevant theory for using heterodyne XPCS to measure velocities in uniform and Couette flows.

Doppler Lidar in the Wind Forecast Improvement Projects

This paper will provide an overview of some projects in support of Wind Energy development involving Doppler lidar measurement of wind flow profiles. The high temporal and vertical resolution of these profiles allows the uncertainty of Numerical Weather Prediction models to be evaluated in forecasting dynamic processes and wind flow phenomena in the layer of rotor-blade operation.

S0520105 二次元偏光計測および流動場観察による圧力振動場における気泡近傍の流体の変形様式

We have studied the motion of a bubble in the viscoelastic fluid under pressure oscillation field. In this field, the bubble rising velocity is accelerated to 400 times compared to the static pressure field. At this time, it is expected that the complex flow will occur around the bubble. An experimental measurement of local flow profile around a bubble obtained by visualization technique is presented; that is used to estimate an enhancement in pressure oscillation defoaming (POD) performance. I used droplets of ink and laser sheet in this flow visualization experiments. We detected velocity vector using the Particle-Image-Velocimetry (PIV) method. In addition, we have calculated the distribution of the shear rate from these velocity vector. In this result, there is a high shear field in the bubble bottom, and it represents the deformation caused by the complex flow at the tail of bubble. This shear rate profile is similar to the results of the stress distribution obtained by the two-dimensional polarization measurement.

Analyses of solid flow in latest design COREX shaft furnace by physical simulation

The present investigation was aimed at elucidating solid particle behaviour in a new design COREX shaft furnace using a new technique called areal gas distribution (AGD). The measurement of solid flow profile was performed with a semi-cylindrical model. To guarantee similarity of conditions, a modified Froude number was taken into consideration in the physical model constructed. The solid flow characteristics in this new furnace with different blast volumes were analysed, and the effect of discharge rate as well as abnormal conditions on solid flow behaviour have also been investigated. The work reveals that solid flow profile in the shaft furnace model progresses through a Flat→Wave→W shape profile as the burden descends. Blast volume has little influence on solid particle behaviour. However, increasing the discharge rate has an effect of decreasing the quasi-stagnant zone size and with the increasing discharge rate, the cross-section of AGD channel increases. For asymmetric flow, particles descend from the top and move to the discharging outlet and a very big stagnant zone is formed on the opposite side of the discharging outlet.

Electrical resistance tomography (ERT) for flow and velocity profile measurement of a single phase liquid in a horizontal pipe

Electrical resistance tomography (ERT) is a novel, simple, and robust method of process imaging which uses non-invasive sensors located on the periphery of vessels to reconstruct a cross-sectional image of the vessel interior. This method of imaging when conducted on two adjacent planes on a pipe provides the ability to extract flow information. Previous studies have investigated this application on multi-phase flows in which the secondary phase provided the required pulse conductivity variation. In these studies the velocity profile and flow regime were identified using the common cross-correlation technique.This study investigates the novel application of ERT to single phase flow and velocity profile measurement. For this purpose a new measurement technique is also developed which excludes the limitation of “pulse” conductivity change in the cross-correlation technique. This new technique has been applied to saline flow and velocity profile measurement using a “step” change in the flow conductivity. The effect of flow speed, ERT measurement frequency, secondary solution conductivity and addition volume has also been investigated and the optimum settings selected. The optimum settings for this experimental setup resulted in an average accuracy of 97.0% for a secondary solution with conductivity more than twice the primary solution conductivity and 94.8% for a secondary solution with conductivity ∼67% more than the primary solution conductivity. This application and accuracy level has been further confirmed through 13%, 24% and 47% total solids content whole and skim milk experiments which resulted in an average accuracy of over 98%.

Time-resolved OCT-μPIV: a new microscopic PIV technique for noninvasive depth-resolved pulsatile flow profile acquisition

In vivo acquisition of endothelial wall shear stress requires instantaneous depth-resolved whole-field pulsatile flow profile measurements in microcirculation. High-accuracy, quantitative and non-invasive velocimetry techniques are essential for emerging real-time mechano-genomic investigations. To address these research needs, a novel biological flow quantification technique, OCT-μPIV, was developed utilizing high-speed optical coherence tomography (OCT) integrated with microscopic Particle Image Velocimetry (μPIV). This technique offers the unique advantage of simultaneously acquiring blood flow profiles and vessel anatomy along arbitrarily oriented sagittal planes. The process is instantaneous and enables real-time 3D flow reconstruction without the need for computationally intensive image processing compared to state-of-the-art velocimetry techniques. To evaluate the line-scanning direction and speed, four sets of parametric synthetic OCT-μPIV data were generated using an in-house code. Based on this investigation, an in vitro experiment was designed at the fastest scan speed while preserving the region of interest providing the depth-resolved velocity profiles spanning across the width of a micro-fabricated channel. High-agreement with the analytical flow profiles was achieved for different flow rates and seed particle types and sizes. Finally, by employing blood cells as non-invasive seeding particles, in vivo embryonic vascular velocity profiles in multiple vessels were measured in the early chick embryo. The pulsatile flow frequency and peak velocity measurements were also acquired with OCT-μPIV, which agreed well with previous reported values. These results demonstrate the potential utility of this technique to conduct practical microfluidic and non-invasive in vivo studies for embryonic blood flows.

Flow profile measurement in microchannel using the optical feedback interferometry sensing technique

The need to accurately measure flow profiles in microfluidic channels is well recognised. In this work, we present a new optical feedback interferometry (OFI) flow sensor that accurately measures local velocity in fluids and enables reconstruction of a velocity profile inside a microchannel. OFI is a self-aligned interferometric technique that uses the laser as both the transmitter and the receiver thus offering high sensitivity, fast response, and a simple and compact optical design. The system described here is based on a commercial semiconductor laser and has been designed to achieve a micrometer-range spatial resolution. The sensor performance was validated by reconstructing the velocity profile inside a circular cross-section flow-channel with 320 $$\upmu $$ m internal diameter, with a relative error smaller than 1.8 %. The local flow velocity is directly measured, thus avoiding the need for model based profile calculation and uncertainties inherent to this approach. The system was validated by successfully extracting the flow profiles in both Newtonian and shear-thinning liquids.

In vivo two-photon excited fluorescence microscopy reveals cardiac- and respiration-dependent pulsatile blood flow in cortical blood vessels in mice

Subtle alterations in cerebral blood flow can impact the health and function of brain cells and are linked to cognitive decline and dementia. To understand hemodynamics in the three-dimensional vascular network of the cerebral cortex, we applied two-photon excited fluorescence microscopy to measure the motion of red blood cells (RBCs) in individual microvessels throughout the vascular hierarchy in anesthetized mice. To resolve heartbeat- and respiration-dependent flow dynamics, we simultaneously recorded the electrocardiogram and respiratory waveform. We found that centerline RBC speed decreased with decreasing vessel diameter in arterioles, slowed further through the capillary bed, and then increased with increasing vessel diameter in venules. RBC flow was pulsatile in nearly all cortical vessels, including capillaries and venules. Heartbeat-induced speed modulation decreased through the vascular network, while the delay between heartbeat and the time of maximum speed increased. Capillary tube hematocrit was 0.21 and did not vary with centerline RBC speed or topological position. Spatial RBC flow profiles in surface vessels were blunted compared with a parabola and could be measured at vascular junctions. Finally, we observed a transient decrease in RBC speed in surface vessels before inspiration. In conclusion, we developed an approach to study detailed characteristics of RBC flow in the three-dimensional cortical vasculature, including quantification of fluctuations in centerline RBC speed due to cardiac and respiratory rhythms and flow profile measurements. These methods and the quantitative data on basal cerebral hemodynamics open the door to studies of the normal and diseased-state cerebral microcirculation.

Measuring Flow Profiles and Slip by Single Molecule Tracking Experiments in Thin Liquid Films

A method for analyzing single molecule tracking data is presented, which allows the measurement of flow profiles in shear flows of ultrathin liquid films. The results show that the velocity profile detected by single molecule tracking is in general different from the analytical solution of the Navier−Stokes equation due to the diffusion of the probe molecules. However, the theory presented allows the extraction of even slip boundary phenomena, which for the first time provides access to boundary conditions on a molecular scale. A verification of the theory and its capabilities is presented by means of tracking single polystyrene particles in a 500 nm thin water film confined in a surface forces apparatus.