Velocity Measurement Method Research Articles

The data assimilation of volumetric velocity and temperature data to extract boundary conditions for high-fidelity simulation of the indoor air

The contemporary challenge of the air conditioning sector is to continuously improve the provided comfort conditions while reducing the energy consumption of the devices. This necessity can only be satisfied by improving research and design methods. Therefore, on the one hand, researchers worldwide develop and utilize experimental methods for more accurate measurements. On the other hand, researchers develop numerical methods to investigate design iterations effectively and quickly.The main idea of this study is to create a novel data assimilation method to utilize all the advantages of experimental and numerical methods to develop a high-fidelity investigation method of an indoor air model.In the present study, the three-dimensional velocity distribution at the split air conditioning indoor unit's outlet section was measured by using the Stereo Particle Image Velocity Measurement method. The temperature distribution at the outlet section of the split air conditioning indoor unit was also determined using the Meshed Infrared Thermography method. The data from these experimental measurements were assimilated to generate a highly realistic boundary condition of the steady-state and time-dependent Computational Fluid Dynamics (CFD) models. This is achieved for the first time in the literature.The results of these analyses compared with conventional CFD and the aforementioned experimental methods. The study's results show that the novel data assimilation approach (3.13% average error) is significantly more accurate than the traditional average boundary condition approach (13.19% average error).

How to Obtain a Detailed SAR Pattern of Currents on the Ocean Surface

At present, the generally accepted method for remote measurement of current velocity on the ocean surface is to determine the Doppler centroid, i.e., the position of the maximum of backscattered radar signal Doppler spectrum (see, for example, [1] and the list of references given there). However, this measurement, generally speaking, is not enough to reconstruct a detailed pattern of the curents

A model for multiphase flow velocity calculation in pipelines based on ultrasonic sensors

In the petroleum and natural gas industry, a wide variety of multiphase fluids are prevalent, and precise measurement of their flow velocity in pipelines holds significant importance for different stages of well drilling and construction. However, due to the presence of large solid particles and the corrosive nature of the liquid phase in multiphase fluids within the petroleum industry, invasive measurement methods struggle to maintain long-term acceptable detection accuracy. Therefore, the non-contact fluid flow velocity measurement method based on ultrasonic sensors exhibits substantial research value. Nonetheless, when employing this approach for pipeline multiphase fluid flow velocity measurement, the abundance of background interference noise at the site poses challenges in Doppler echo signal reconstruction and results in lower precision for frequency shift extraction, leading to considerable errors in flow velocity calculation results. To address this issue, the present study utilizes a transmit-receive separated continuous wave ultrasonic sensor. First, a mathematical model is developed for the superimposed signal of ultrasonic Doppler echoes within the pipeline. Next, a novel signal reconstruction method is proposed by employing Chebyshev polynomials for interpolation computation of the sampled discrete signals. Subsequently, a Doppler shift model is introduced, leading to the formulation of a new model for multiphase flow velocity calculation in pipelines based on ultrasonic sensors. Finally, a comparison experiment for full-pipe multiphase flow velocity detection is conducted to validate the computational performance of the new model. The experimental results show that, compared with the FFT model and the conventional cross correlation model, the comprehensive meter factor of the ultrasonic flow measurement system with the new model is reduced by 0.024 445, the accuracy is reduced by 2.98%, the nonlinear error is reduced by 2.4405%, the average relative error is reduced by 0.646%, the standard deviation is reduced by 0.045 175, and the root mean squared error is reduced by 0.029 615.

Fundamental Study on the Development of an Inexpensive Velocity Meter for River Floods Using Stagnation Points

In recent years, climate change has occurred on a global scale, causing frequent flooding in many regions. In response to this situation, watershed-wide flood management is attracting attention around the world as a promising approach. Under these situations, Japan has also made a policy shift to watershed-based flood management, which aims to manage floods and control runoff in the entire watershed. For this management, it is essential to obtain areal hydraulic information, especially flow information, from each location in the watershed. To measure river flow, it is necessary to measure water level and velocity. While it is becoming possible to make area-based observations of water levels using simple methods, various attempts have been made to measure the velocity, but continuous data cannot be obtained using simple methods. Low-cost flow velocity meters would facilitate the simultaneous and continuous accumulation of data at multiple points and enable the acquisition of areal flow information for watersheds, which is important for watershed-based flood management. This study aims to develop an inexpensive, simple velocity meter that can be used to make areal measurements within watersheds, and to make this velocity meter usable by residents, thereby contributing to citizen science. Therefore, experimental studies were conducted on a method of measuring flow velocity based on the simple physical phenomenon of rising water surface elevations due to increased pressure at the stagnation point. First, we placed the cylinders in the river or waterway, observed the afflux, and compared the velocities calculated using Bernoulli’s theorem with the velocities at the experimental site. By multiplying the calculated flow velocity by 0.9, the average flow velocity was found to be obtained. Then, by using a large pitot tube with a hole diameter of about 5 mm, the rise in water level in the pitot tube was measured using a pressure-type water level meter, and the flow velocity was calculated using the pitot tube theory and compared with the flow velocity at the location of the hole at the experimental site. By multiplying the calculated velocity by 1.04, the velocity at the location of the hole can be obtained. In addition, the same experiment was conducted using a pitot tube with a slit. The slit tube was placed vertically with the slit facing upstream. Measurements were taken in the same method as for the pitot tube velocity meter and compared to the velocity at that point. By multiplying the calculated flow velocity by 0.99, the average flow velocity at that location can be obtained. These results indicate that a flow velocity measurement method utilizing stagnation points can lead to the development of inexpensive velocity meters. Because of the simplicity of this meter, there is a possibility that citizens can participate in the observation to obtain information on the flow velocity during floods and areal information within a watershed.

Research on weighted carrier phase three difference precision velocity measurement method based on BDS / GPS integrated system

Aiming at the problem of velocity measurement accuracy in single system carrier phase differential velocity measurement and the possible cycle slip in the process, a carrier phase three difference method is proposed to further improve the velocity measurement accuracy. The use of carrier phase triple difference positioning has been very mature, but there is not much research in velocity measurement. Therefore, this paper uses carrier phase triple difference for velocity measurement. At the same time, in order to improve the cycle slip problem in the process, an integral Doppler double difference combined with carrier phase triple difference is proposed, and then a method to improve the cycle slip based on weight is obtained. Both static and dynamic tests show that the carrier phase triple difference method can improve the speed measurement accuracy, and the weighted carrier phase triple difference method can improve the cycle slip.

Cohesive collisions of particles in liquid media studied by CFD-DEM, video tracking, and Positron Emission Particle Tracking

This paper investigates the cohesive collision of ice in an oil phase at temperatures ranging from −15.7 °C to −0.3 °C. The new information on the coefficient of restitution (COR) was obtained using three different velocity measurement methods: high-speed experimental video recording, Positron Emission Particle Tracking (PEPT), and numerical simulations. A new type of PEPT tracer was developed for the experiments. The COR values were in the interval 0.57...0.82, with a maximum at around −10 °C. The CFD-DEM coupled approach was applied to reproduce experiments with an ice particle drop and its collision with an inclined ice surface in a decane. The particle–wall interaction is modeled using commercial software, considering particle cohesion, particle size, and shape. CFD-DEM predicted the COR with an average deviation ∼10% from the experimental data. The numerical model’s results agree with the experiments, demonstrating that the CFD-DEM method is suitable for describing multiphase cohesive interactions.

Association between the triglyceride-glucose index and arterial stiffness: A meta-analysis.

Studies have shown a strong association between the triglyceride-glucose (TyG) index, a simple marker of insulin resistance, and various metabolic diseases. We performed a systematic review of the interaction between the TyG index and arterial stiffness. Relevant observational studies assessing the association between the TyG index and arterial stiffness were thoroughly searched in PubMed, Embase, and Scopus, and a manual search of the preprint server was conducted. A random-effects model was utilized to analyze the data. The risk of bias for the included studies was assessed using the Newcastle-Ottawa Scale. A pooled effect size estimate with a random-effects model was used for the meta-analysis. Thirteen observational studies comprising 48,332 subjects were included. Of these, 2 were prospective cohort studies, and the remaining 11 were cross-sectional studies. According to the results of the analysis, the risk of developing high arterial stiffness was 1.85 times greater for those in the highest TyG index subgroup versus the lowest group (risk ratio [RR]: 1.85, 95% confidence interval: 1.54-2.33, I2 = 70%, P < .001). Consistent results were observed when the index was analyzed as a continuous variable (RR: 1.46, 95% confidence interval: 1.32-1.61, I2 = 77%, P < .001). A sensitivity analysis excluding each of the studies one by one yielded similar results (RRs for categorical variables: 1.67-1.94, P all <.001; RRs for continuous variables: 1.37-1.48, P all <.001). A subgroup analysis showed that different characteristics of the study subjects, such as type of study design, age, population, disease status, (including hypertension and diabetes), and pulse wave velocity measurement methods had no substantial effect on the results (P for subgroup analysis, all >0.05). A relatively high TyG index might be linked to an increased incidence of arterial stiffness.

Development of Measurement Method for Temperature and Velocity Field with Optical Fiber Sensor.

We have developed a new method for measuring temperature and velocity at a high spatial resolution (minimum 2.56 mm pitch along an optical fiber). The developed method uses the same principle as a hot wire anemometer, where the velocity perpendicular to an optical fiber is estimated as a function of the cooling curve of a gold-coated layer on the optical fiber Joule-heated intermittently. The developed optical fiber sensor demonstrated the ability to acquire a transient velocity profile in airflow experiments with high repeatability and accuracy. This paper describes optical fiber-based velocity measurement in the velocity range of approximately 0-7 m/s with an error of approximately 10% compared to a hot wire anemometer and a new method for simultaneous temperature and velocity measurements. Applicability to velocity distribution measurements and seconds transient velocity changes are also described.

A Velocity Measurement Method Based on Charge Induction.

In this paper, based on the principle of charge induction, a new velocity measurement method is proposed. A moving target generates a low-frequency electric field, which can be induced with an electrode and detection frontend. Velocity measurements are achieved by placing two electrodes at a fixed distance to detect the characteristic times. Firstly, the electric field generated by the moving target is modeled, and the theoretical output of the detection frontend is obtained via a simulation of the target passing by a single electrode. Then, according to the theoretical output, the velocity measurement simulation results of double electrodes are given for various driving conditions, such as a single vehicle driving in a single lane, a single vehicle changing lanes, two vehicles driving close together, and a multiple-vehicle situation. Finally, the above driving conditions are experimentally verified in sunny weather, windy and rainy weather, and a night environment.

An ultrasound-based monitoring of kaolinite flocculent settling processes

In order to implement real-time monitoring of flocculent settling processes, an ultrasonic method based on the ECAH model was proposed and studied, particularly by considering the influence of particle irregularity on sound attenuation. Numerical simulations were conducted to evaluate the influence of critical physical parameters’ variation on the attenuation coefficient. Meanwhile, an integrated experimental system including ultrasonic measurement, interface settling velocity measurement, microscopic imaging and online sampling methods was established. The experiments of kaolinite particle suspensions with four different initial mass concentrations were carried out, and the phenomenon of flocculation and settling was observed accordingly. The duration of each settling stage and its change rate were analyzed simultaneously by both the interface settling velocity and ultrasonic attenuation coefficient. The analysis results show that for the same flocculent settling stage, the relative deviation of duration obtained by two methods above were 0%, 7.32%, −10.57%, 1.62% and 1.63%, respectively. The mechanisms and characteristics of each stage in the precipitation process were discussed in detail. At the same time, the volume concentrations obtained by ultrasonic method were compared with the results of weighing after on-line sampling. The deviations under the four initial mass concentrations were 18.6%, 12.1%, 11.0% and 13.2% respectively. The correlation between the process of flocculation and ultrasonic parameters was established accordingly, which provided data support for the application of ultrasonic technique to the online detection of kaolinite particle flocculent settling processes.

PROBLEMS OF MEASURING LOW FEED RATES OF METAL CUTTING EQUIPMENT

The article is dedicated to the problem formulation of improving the method for measuring low feed rates in metal-cutting machines during finishing operations by using direct speed measurement sensors. The goal of the work is to review the issue of measuring low feed rates in blade machining in order to assess and minimize the uncertainties of feed rate measurements. The necessity of measurements and subsequent analysis of feed rate instabilities in metal-cutting machines within the range of 0 to 20 mm/min is demonstrated. It is shown that the uneven movement of machine tool elements can be a result of clearances in movable joints and overcoming friction forces in these clearances. The influence of the adaptive control system of the machine tool drive on the unevenness of feed rate is also presented. The effect on the unevenness of feed rate of different types of drives is described, including stepper motors, hydraulic and pneumatic drives, asynchronous motors with frequency converters, and servo motors. The main components of uncertainty arising from the indirect method of velocity measurement are described, related to uncertainties in time and distance measurement, errors in approximation during instantaneous velocity calculation, as well as errors associated with the discretization of time and distance measurements. Methods of direct feed rate measurement are discussed. It is shown that it is not possible to use sensors utilizing the Doppler effect for measuring small feed rates. It is noted that existing designs of magnetic velocity sensors have significant nonlinearity, which cannot be eliminated by adjusting measurement results. Limitations of known sensors regarding the length of the path on which the feed rate can be measured are specified. A promising direction for research on improving the method of direct measurement of small feed rates in metal cutting machines is identified.

Comparison of Doppler-Derived Sea Ice Radial Surface Velocity Measurement Methods From Sentinel-1A IW Data

The near-instantaneous radial velocity of a target can be obtained using the Doppler effect of SAR, which is widely used in ocean current retrieval. However, in sea ice drift velocity measurements, only a Doppler centroid estimation algorithm in frequency domain has been studied, so whether there is a better algorithm is worth exploring. In this study, based on Sentinel-1A IW data, three Doppler centroid estimation algorithms applied to ocean current retrieval are selected. Combined with the characteristics of the TOPS mode, made two applicability adjustments to each algorithm, and finally applied the three algorithms to sea ice radial surface velocity measurements. The first adjustment is to explore and determine the optimal parameters. The second adjustment is to use parallel computing to improve the efficiency, which is improved by an average of 43.55%. In addition, the deviation of Doppler centroid estimation bias correction is verified using rainforest data, and the deviation is controlled at approximately 3 Hz. Based on the three algorithms, five sets of experiments are carried out in this study. By analyzing and comparing the results of each algorithm, it is found that the results of the three algorithms are relatively consistent, among which the correlation Doppler estimation algorithm has the advantages of high efficiency and high precision and is the most suitable method for sea ice drift measurement among the three methods. However, for SAR images with abnormal speckles caused by human activities, the sign Doppler estimation algorithm can effectively remove abnormal speckles and ensure the smoothness of the image with better adaptability.

Research on velocity measurement method of rocket engine tail flame particle based on quantum filter and tracking algorithm

Research on velocity measurement method of rocket engine tail flame particle based on quantum filter and tracking algorithm

Instantaneous velocity measurement method of projectile with double ballistic zone-block apparatus

传统测试方法采用区截装置进行弹丸测速，总是假设弹丸为匀速直线运动，忽略了空气阻力等因素的影响。基于空气动力学及理论力学原理，提出一种使用两套区截测速装置进行弹丸瞬时速度测试的方法。该方法通过两个相距一定距离的测速点的速度值，计算测试过程中弹丸在测试区域飞行的速度衰减系数<i>B</i>，并通过<i>B</i>值计算得到测试区域附近弹道内任意点的瞬时速度。仿真分析表明，该方法在0.8倍音速以内的相对测量误差小于0.01%，远低于0.1%的工程误差要求。弹弓、气枪和步枪实弹实验发现，弹丸飞行速度在0.8倍音速以内或1.2倍音速以上的测试精度不低于所采用区截测速装置0.1%的精度，验证了此方法的可行性。研究为弹道综合参数测试系统的设计和优化提供了新的思路和方法。

Method for simultaneous measurement of velocity and direction of fluid flow using fiber Bragg gratings

This work is devoted to the development and research of a new optical method for measuring the velocity of a fluid flow and determining the orthogonal directions of such a flow. Comparing with gas flow, measuring the fluid flow rate requires higher heating power and insulation, which is taken into account in this work. The standard hot-wire anemometry method is taken as a basis, but instead of a metal thread, optical fiber is used for measurements. The article presents the design of a sensitive element consisting of two optical fibers. The first fiber contains an array of fiber Bragg gratings and is used as a measurement element. The second fiber has a region with a tapered structure and is used to create a heated area. Velocity measurements are given for the range of 0.02–0.05 m/s, but are limited only by the capabilities of the measuring stand. A unique method for identifying the orthogonal flow direction, which has not been described in the literature before, is presented. Differences in the shapes of the curves for the dependences of flow rates moving in the direction and orthogonally to the axis of the sensitive element are presented. The stability of the device is also confirmed by continuous experiments for 70 min.

On-board Dynamic Measuring of Long-wave Track Irregularity based on Visual Inertial Fusion

This paper studies an inspection method to measure the long-wave track irregularities using the signals of IMU (Inertial Measurement Unit) and Laser & Camera installed on a bogie, which is implemented in comprehensive inspection trains. To reduce the influence of random noise and vehicle vibration, the mechanical structure is optimized; the spatial-dependent change of the "two-point chord" on the track is observed by high-precision FOC (Fiber Optic Gyroscope) and laser camera components; the angular velocity measurement method is deduced. To eliminate high-frequency attenuation of the signal, a sensor fusion algorithm based on the concept of complementary filters is presented. The angular velocity-based method is also used to measure low spatial frequencies, while the acceleration-based method is used to measure high spatial frequencies. The measurement accuracy of the system is evaluated from two aspects: internal and external coincidence accuracy. The test shows that the repeatability accuracy of the system to alignment and profile of the wavelength of 200 m is 0.5 mm and 0.8 mm, respectively, and the trend item and the line design value maintain good consistency.

A Data Assimilation Approach to the Modeling of 3D Hydrodynamic Flow Velocity in River Reaches

The measurement of river discharge is essential for sustainable water resource management. The velocity–area approach is the most common method for calculating river discharge. Although several velocity measurement methods exist, they often have varying degrees of technical issues attributed to their operational complexity, time effectiveness, accuracy, and environmental impact. To address these issues, we propose a three-dimensional (3D) hydrodynamic model coupled with data assimilation (DA) for velocity measurement with improved accuracy and efficiency. We then apply this model to the Lanxi River reach in Zhejiang Province, China. The experimental results confirm that the obtained assimilated velocities using our proposed algorithm are much closer to the observed velocities than the simulated velocities. Our results show that when using the proposed method, the RMSE is decreased by 78%, and the SKILL and DASS values are 0.96 and 0.92, respectively. These confirm that the DA scheme of the flow velocity measurement is effective and capable of significantly improving the accuracy of the velocity with lower computational complexity.

Abstract 13216: Evaluation of Left Ventricular Flow Propagation Velocity From Multi-Dimensional Cardiac Imaging

Introduction: The propagation velocity (Vp) during the left ventricular (LV) early diastole has been proposed as a marker of the diastolic function. However, the measurement of Vp is limited to one-dimensional data from Color M-mode (CMM) echocardiography and does not consider the spatiotemporal variation of Vp. Methods: We introduce a new method to evaluate the LV diastolic flow propagation from multi-dimensional cardiac flow imaging. The proposed method estimates the local and instantaneous flow propagation velocity (V prop ) by fitting the first order wave equation to the velocity gradients with weighted least-squares. The proposed method was validated using the synthetic vortex ring flow data. The method was applied to the LV flow data acquired with two-dimensional phase-contrast magnetic resonance imaging (pc-MRI) and 4D flow MRI. Results: The V prop estimated from multi-dimensional data has about 50% less error than the V prop from one-dimensional data. Fig. 1(a) shows the waveforms of the mitral inflow velocity, the IVPD, and the propagation intensity (I prop ) during the LV diastole of a normal filling patient. During early diastole, the timing of peak flow propagation coincides with the peak intraventricular pressure difference. Fig. 1(b) presents the fields of the blood flow velocity, the V prop , and the relative pressure from the timeframes indicated using the dotted lines in the waveform plots. The flow propagation towards the apex is mainly located at the front of the inflow jet and downstream of the vortex ring formed near mitral valve tips. Conclusions: This study introduces a novel propagation velocity measurement method for multi-dimensional cardiac flow imaging and demonstrated the V prop ’s spatial distribution temporal evolution.

Impact Velocity Measurement Method Based on Trajectory and Impact Position.

The impact velocity of falling weight is an instantaneous quantity. Currently, measurement of impact velocity relies on high-speed sensors to capture the moment of impact. The trajectory-position measurement method (TPMM) is proposed in this study. The main steps are: (1) The impact position is used to capture the impact time. It can be measured when the falling weight is stationary. (2) The discrete falling trajectory is measured and a new empirical regression algorithm is proposed to fit the expression of falling trajectory. (3) The impact velocity is obtained by taking the impact time into the first derivative of the trajectory expression. For 1-5 m falling height, the simulation shows that the relative maximum error and relative expanded uncertainty of the proposed method are less than 0.481% and 0.442%, respectively. Then, the actual experiment is carried out to verify the simulation. The proposed method has high accuracy and low uncertainty. The reasons are: (1) Only a low-speed displacement sensor is need for impact velocity measurement. It is easier to improve accuracy and stability of a low-speed sensor. (2) The empirical regression algorithm can improve the stability of falling trajectory fitting.

Development of an Estimation Method for Depth of Spalling Damage in Concrete Pavement by Ultrasonic Velocity Measurement

As the amount of aged pavement increases, functional damage, such as spalling, occurs frequently on Portland Cement Concrete pavement (PCC) in South Korea. However, the existing management method does not properly reflect the scope of deterioration of the pavement causing early damage. To overcome the problem of the existing repair method, this study evaluated the deterioration of functional damage on the surface of the slab as soundness through ultrasonic velocity measurement method among non-destructive testing (NDT) techniques and suggested a method to estimate the depth of deterioration. To develop a method for estimating the depth of the deterioration a slab, a preliminary investigation was conducted to check the range of ultrasonic velocity of concrete pavement in South Korea and to evaluate the variability of NDT equipment. Based on the ultrasonic velocity, the sound rating of concrete pavement was graded from 5 for “very good” to 0 for “very poor”, and the tendency of the ultrasonic velocity to increase according to the depth of the deteriorated areas was confirmed.