Calculation of cross-section average flow velocity in vegetated compound channels

2011 ◽  
Author(s):  
Chao Liu ◽  
Yuqi Shan ◽  
Kejun Yang ◽  
Xingnian Liu
Keyword(s):  
Flow Velocity ◽  
Cross Section ◽  
Compound Channels ◽  
Average Flow ◽  
Average Flow Velocity

scholarly journals Optimized Vegetation Density to Dissipate Energy of Flood Flow in Open Canals

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Mahdi Feizbahr ◽  
Navid Tonekaboni ◽  
Guang-Jun Jiang ◽  
Hong-Xia Chen
Keyword(s):  
Flow Velocity ◽  
Cross Section ◽  
Flow Resistance ◽  
Vegetation Density ◽  
Flow Conditions ◽  
Average Flow ◽  
Flow Energy ◽  
Average Flow Velocity ◽  
Flow Velocity Profile ◽  
Flood Flow

Vegetation along the river increases the roughness and reduces the average flow velocity, reduces flow energy, and changes the flow velocity profile in the cross section of the river. Many canals and rivers in nature are covered with vegetation during the floods. Canal’s roughness is strongly affected by plants and therefore it has a great effect on flow resistance during flood. Roughness resistance against the flow due to the plants depends on the flow conditions and plant, so the model should simulate the current velocity by considering the effects of velocity, depth of flow, and type of vegetation along the canal. Total of 48 models have been simulated to investigate the effect of roughness in the canal. The results indicated that, by enhancing the velocity, the effect of vegetation in decreasing the bed velocity is negligible, while when the current has lower speed, the effect of vegetation on decreasing the bed velocity is obviously considerable.

scholarly journals Investigation of ultrasonic flowmeter error in distorted flow using two-peak Salami functions

2021 ◽  
Vol 7 (2) ◽  
pp. 144-151
Author(s):  
Fedir Matiko ◽  
◽  
Vitalii Roman ◽  
Halyna Matiko ◽  
Dmytro Yalinskyi
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Cross Section ◽  
Ultrasonic Flowmeter ◽  
Additional Error ◽  
Average Flow ◽  
Research Results ◽  
Pipe Cross Section ◽  
Average Flow Velocity ◽  
Flow Velocity Profile

Results of investigating the additional error of ultrasonic flowmeters caused by the distortion of the flow are presented in the article. The location coordinates of acoustic paths were calculated for their number from 1 to 6 according to the different numerical integrating methods: Gauss (Gauss-Legendre, Gauss-Jacobi), Chebyshev (equidistant location of acoustic paths), Westinghouse method, method of OWICS (Optimal Weighted Integration for Circular Sections). This made it possible to realize the flowrate equation for multi-path ultrasonic flowmeters and to determine their additional error for different location of the acoustic paths. The average flow velocity along each path is calculated based on the flow velocity profile in the pipe cross section. Four two-peak Salami functions of velocity are used to calculate the velocity profile of the distorted flow caused by typical local resistances. According to the research results the recommendations were developed for choosing the number of the acoustic paths of the ultrasonic flowmeters and for using the methods for determining the location coordinates of the acoustic paths.

scholarly journals Влияние на аномальную интенсификацию отрывного турбулентного течения угла наклона однорядных овально-траншейных лунок на стабилизированном гидродинамическом участке узкого канала

2020 ◽  
Vol 46 (21) ◽  
pp. 18
Author(s):  
С.А. Исаев ◽  
А.Б Мазо ◽  
Д.В. Никущенко ◽  
И.А. Попов ◽  
А.Г. Судаков
Keyword(s):  
Flow Velocity ◽  
Narrow Channel ◽  
Swirling Flows ◽  
Secondary Flows ◽  
Average Flow ◽  
Dramatic Effect ◽  
Average Flow Velocity ◽  
Negative Friction

The slope of the oval-trench dimple in the corridor package on the hydrodynamic stabilized section of the narrow channel has a dramatic effect on the anomalous intensification of returned and swirling flows in the dimple, leading to a 3–4-fold decrease in relative negative friction in the range of angles from 40° to 60°, an increase in the highest speed return and secondary flows up to 0.8 and 1.18 with respect to the mass-average flow velocity in the channel.

scholarly journals ASYMMETRIC FLOW VELOCITY MEASUREMENT USING MULTIPATH ULTRASONIC FLOWMETER WITH ADAPTIVE WEIGHTING METHOD GUIDED BY TOMOGRAPHY

2019 ◽  
Vol 82 (1) ◽  
Author(s):  
Khairul Amri ◽  
Suprijanto Suprijanto ◽  
Deddy Kurniadi ◽  
Endang Juliastuti
Keyword(s):  
Flow Velocity ◽  
Mapping Function ◽  
Flow Profile ◽  
Asymmetric Flow ◽  
Weighting Method ◽  
Alternative Scheme ◽  
Average Flow ◽  
Average Flow Velocity ◽  
Adaptive Weighting ◽  
Flow Profiles

A conventional transit time ultrasonic flowmeter (USM) has a high accuracy for symmetric flow profiles but inaccurate for asymmetric flow profiles. Flow profile shapes can also change over time and difficult to predict. USM with tomographic configuration (USM-Tomo) can adapt to the flow profile changes but result in low temporal resolution. Meanwhile, USM with an adaptive weighting method can measure asymmetric flow velocity but limited to specific asymmetric flow profiles. An alternative scheme to determine adaptive weighting in various asymmetric flow profiles, we proposed a hybrid USM-Tomo. This scheme proposes programmable acoustic path configuration that could set the path mode between USM and tomography. Reducing computation of time of flight in each acoustic can be done by applying the dual-transducers technique. An adaptive weighting of hybrid USM-Tomo is calculated based on the mapping function between the set of velocity on 6 parallel paths of USM and average flow velocity from USM-Tomo. The mapping function is determined using machine learning, i.e., Artificial Neural Network (ANN) and Support Vector Regression (SVR). In the measurement phase, the average flow velocity is determined using the mapping function with input 6 parallel acoustic paths.  Based on various types of asymmetric flow profiles used in the experiment, the 6 parallel acoustic paths of USM could produce average flow velocity with error below 1% compared to USM-Tomo. Therefore, the proposed hybrid USM-Tomo scheme has potential to be an alternative scheme for flow meter in industrial application.

scholarly journals Analysis of fluid flow around a beating artificial cilium

2012 ◽  
Vol 3 ◽  
pp. 163-171 ◽  
Author(s):  
Mojca Vilfan ◽  
Gašper Kokot ◽  
Andrej Vilfan ◽  
Natan Osterman ◽  
Blaž Kavčič ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Velocity ◽  
Rotation Frequency ◽  
Model Systems ◽  
Basic Principles ◽  
Average Flow ◽  
Average Flow Velocity ◽  
Tracer Particles ◽  
Beat Pattern ◽  
Unicellular Organisms

Biological cilia are found on surfaces of some microorganisms and on surfaces of many eukaryotic cells where they interact with the surrounding fluid. The periodic beating of the cilia is asymmetric, resulting in directed swimming of unicellular organisms or in generation of a fluid flow above a ciliated surface in multicellular ones. Following the biological example, externally driven artificial cilia have recently been successfully implemented as micropumps and mixers. However, biomimetic systems are useful not only in microfluidic applications, but can also serve as model systems for the study of fundamental hydrodynamic phenomena in biological samples. To gain insight into the basic principles governing propulsion and fluid pumping on a micron level, we investigated hydrodynamics around one beating artificial cilium. The cilium was composed of superparamagnetic particles and driven along a tilted cone by a varying external magnetic field. Nonmagnetic tracer particles were used for monitoring the fluid flow generated by the cilium. The average flow velocity in the pumping direction was obtained as a function of different parameters, such as the rotation frequency, the asymmetry of the beat pattern, and the cilium length. We also calculated the velocity field around the beating cilium by using the analytical far-field expansion. The measured average flow velocity and the theoretical prediction show an excellent agreement.

scholarly journals Flow Velocity Measurement Using a Spatial Averaging Method with Two-Dimensional Flexural Ultrasonic Array Technology

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4786 ◽  
Author(s):  
Lei Kang ◽  
Andrew Feeney ◽  
Riliang Su ◽  
David Lines ◽  
Sivaram Nishal Ramadas ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Flow Measurement ◽  
Averaging Method ◽  
Spatial Averaging ◽  
Flow Meters ◽  
Average Flow ◽  
Average Flow Velocity ◽  
Array Transducer ◽  
Flow Velocity Measurement ◽  
Ultrasonic Array

Accurate average flow velocity determination is essential for flow measurement in many industries, including automotive, chemical, and oil and gas. The ultrasonic transit-time method is common for average flow velocity measurement, but current limitations restrict measurement accuracy, including fluid dynamic effects from unavoidable phenomena such as turbulence, swirls or vortices, and systematic flow meter errors in calibration or configuration. A new spatial averaging method is proposed, based on flexural ultrasonic array transducer technology, to improve measurement accuracy and reduce the uncertainty of the measurement results. A novel two-dimensional flexural ultrasonic array transducer is developed to validate this measurement method, comprising eight individual elements, each forming distinct paths to a single ultrasonic transducer. These paths are distributed in two chordal planes, symmetric and adjacent to a diametral plane. It is demonstrated that the root-mean-square deviation of the average flow velocity, computed using the spatial averaging method with the array transducer is 2.94%, which is lower compared to that of the individual paths ranging from 3.65% to 8.87% with an average of 6.90%. This is advantageous for improving the accuracy and reducing the uncertainty of classical single-path ultrasonic flow meters, and also for conventional multi-path ultrasonic flow meters through the measurement via each flow plane with reduced uncertainty. This research will drive new developments in ultrasonic flow measurement in a wide range of industrial applications.

scholarly journals Utilization of 6 × 6 cm format vertical aerial photographs for repetitive mapping of surface morphology and measurement of flow velocities of a small glacier in a remote area: Glaciar Soler, Hielo Patagónico Norte, Chile

2002 ◽  
Vol 34 ◽  
pp. 385-390 ◽  
Author(s):  
Masamu Aniya ◽  
Renji Naruse ◽  
Satoru Yamaguchi
Keyword(s):  
Seasonal Variation ◽  
Surface Morphology ◽  
Flow Velocity ◽  
Measured Data ◽  
Aerial Photographs ◽  
Average Flow ◽  
Ablation Area ◽  
Average Flow Velocity ◽  
Northern Patagonia ◽  
Basal Sliding

AbstractUsing vertical aerial photographs taken manually with a 6 × 6 cm format camera in 1984, 1986 and 1999, the surface morphology of the ablation area of Glaciar Soler, Hielo Patagónico Norte (northern Patagonia icefield), Chile, was studied. Glaciar Soler has an area of 50.9 km2; the ablation area below the icefall is about 7 km long and 2 km wide. An uncontrolled aerial-photographic mosaic for the area below the icefall was assembled from 40–60 aerial photographs, on which the surface morphology was mapped from interpretation of stereo pairs of the enlarged photographs (scales of 1:4500 to 1: 8000). Themapped features include debris-free and debris-covered ices, ogive bands and waves, crevasses, supraglacial streams, moulins, medial moraines, troughs and grooves. A total of 32–34 pairs of ogive bands were recognized, from which an average flow velocity of about 160 m a–1 was deduced. The spacing of a pair of light and dark ogive bands indicates that the flow velocity ranges from about 350 ma–1 near the icefall to some 100 ma–1 near the snout. Comparison of the field-measured data with the ogive spacing indicates that the seasonal variation in flow velocity of Glaciar Soler is very large, probably because of variation in the amount of basal sliding.

Optimization Design and CFD Study of Nature Gas Engine Inlet

2013 ◽  
Vol 655-657 ◽  
pp. 315-319
Author(s):  
Yun Jing Jiao ◽  
Peng Kun Si ◽  
Zi Li Zhang
Keyword(s):  
Numerical Simulation ◽  
Cross Section ◽  
Optimization Design ◽  
Velocity Fields ◽  
Simulation Software ◽  
Swirl Ratio ◽  
Gas Engine ◽  
Average Flow ◽  
Average Flow Velocity ◽  
Nature Gas

By adopting CFD numerical simulation software, the steady numerical simulation of original engine inlet is carried on. On base of the original one, two new inlets are redesigned and their velocity fields are analyzed. From the simulation of CFD, we can learn that with the different inlet, the average flow velocity increases when the swirl ratio rises in same cross-section. Then the experiment of inlets with different geometry is carried on. Considered various kinds of performance of the engine, we found that the swirl ratio which is generated by the inlet should not be too high, but it also is not good with too low swirl ratio. In this investigation, comprehensive consideration of economy and power, the no.1 inlet is selected as the best one for the next study.

Experimental Test of Dynamic Moving Characteristics for Leak Detecting-Ball in Water Mains

2014 ◽  
Vol 955-959 ◽  
pp. 3385-3388
Author(s):  
Si Jia Chen ◽  
Yu Shao ◽  
Liang Tao ◽  
Ying Ying Zhao ◽  
Han Feng Jing ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Distribution System ◽  
Water Distribution ◽  
Experimental Tests ◽  
Pipe Diameter ◽  
Average Flow ◽  
Average Flow Velocity ◽  
High Responsiveness ◽  
Water Mains ◽  
Different Diameters

The leak detecting-ball moving in pipes combined the sensors of the acoustic leak detection achieves the high responsiveness to small leaks of the water distribution system (WDS). The dynamic characteristics of the single sphere moving inside pressure pipes are studied for optimal design of the leak detecting-ball. The experimental balls having different densities are made of three types of material by using 3D printing, including tetrafluoroethylene (ETFE), photosensitive resin (PR) and wax. The balls have densities from 1.06 to 1.35 and different diameters, ball-to-pipe diameter ratios from 0.32 to 0.5. The Reynolds numbers of the pipe flows are from 1400 to 50000. The moving velocity of the balls with different pipe flow velocities, ball densities, and ball-to-pipe diameter ratios are investigated through the laboratory experiments. The velocities of balls in some of the experimental tests are greater than the average flow velocity. These larger balls rolled faster than the average flow velocity because of the maximum thrust by the pressure flow in the center of the circular tube section.

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