scholarly journals A Flow-Measuring Algorithm of Arc-Bottomed Open Channels through Multiple Characteristic Sensing Points of the Flow-Velocity Sensor in Agricultural Irrigation Areas

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4504
Author(s):  
Yu Han ◽  
Tongshu Li ◽  
Shiyu Wang ◽  
Jian Chen
Keyword(s):  
Flow Velocity ◽  
Multiple Characteristic ◽  
Velocity Sensor ◽  
Normal Line ◽  
Agricultural Sustainable Development ◽  
Drainage Channels ◽  
Log Law ◽  
Velocity Measuring ◽  
Efficient Water Use ◽  
Channel Type

Precise flow measurement in the open channel is a key prerequisite to implementation of modern agricultural efficient water use. The channel with an arc-bottomed shape is the most common channel type in irrigation area at present. The paper has verified the log-law is along the normal line rather than along the vertical line in arc-bottom channel. By conducting the velocity distribution log-law, this paper derives the expression of the multiple characteristic sensing points location of the flow-velocity sensor in the channel section, which is along the normal line. Based on this, a new algorithm to estimate the discharge of the arc-bottomed channel flow is proposed. We have also developed the experiment of the arc-bottomed channels (including semicircular channels, arc-bottom trapezoidal channels and U-shaped channels) and utilize the data to verify the method. The results indicate that the sensing locations expression of the flow velocity measuring sensor such as acoustic doppler velocimetry and propeller is suitable for improving discharge estimation’s accuracy of the arc-bottomed channels. This method could be extensively used in estimating discharge of irrigation and drainage channels in agricultural water conservancy projects. It will enhance the efficiency and accuracy of water resources management departments in irrigation areas, which also meet the strategic requirements of agricultural sustainable development.

scholarly journals Flow velocity and nutrients affect CO2 emissions from agricultural drainage channels in the North China Plain

2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Peifang Leng ◽  
Fadong Li ◽  
Kun Du ◽  
Zhao Li ◽  
Congke Gu ◽  
...  
Keyword(s):  
Flow Velocity ◽  
North China Plain ◽  
North China ◽  
Groundwater Depletion ◽  
Agricultural Drainage ◽  
Agricultural Practice ◽  
The North ◽  
The North China Plain ◽  
Groundwater Irrigation ◽  
Drainage Channels

Abstract Background Groundwater is typically over-saturated in CO2 with respect to atmospheric equilibrium. Irrigation with groundwater is a common agricultural practice in many countries, but little is known about the fate of dissolved inorganic carbon (DIC) in irrigation groundwater and its contribution to the CO2 emission inventory from land to the atmosphere. We performed a mesocosm experiment to study the fate of DIC entering agricultural drainage channels in the North China Plain. Specifically, we aimed to unravel the effect of flow velocity and nutrient on CO2 emissions. Results All treatments were emitting CO2. Approximately half of the DIC in the water was consumed by TOC production (1–16%), emitted to the atmosphere (14–20%), or precipitated as calcite (CaCO3) (14–20%). We found that DIC depletion was stimulated by nutrient addition, whereas more CO2 evasion occurred in the treatments without nutrients addition. On the other hand, about 50% of CO2 was emitted within the first 50 h under high flow velocity. Thus, in the short term, high nutrient levels may counteract CO2 emissions from drainage channels, whereas the final fate of the produced biomass (burial versus mineralization to CO2 or even CH4) determines the duration of the effect. Conclusion Our study reveals that both hydrology and biological processes affect CO2 emissions from groundwater irrigation channels. The estimated CO2 emission from total groundwater depletion in the North China Plain is up to 0.52 ± 0.07 Mt CO2 year−1. Thus, CO2 emissions from groundwater irrigation should be considered in regional CO2 budgets, especially given that groundwater depletion is expected to acceleration in the future.

An Automatic Paperless Velocity Measuring and Recording System

2014 ◽  
Vol 889-890 ◽  
pp. 745-748
Author(s):  
Jian Sheng Cao ◽  
Wan Jun Zhang ◽  
Xin Hua Zeng
Keyword(s):  
Flow Velocity ◽  
Optical Pulse ◽  
Electric Pulse ◽  
Automatic Monitoring ◽  
Time Intervals ◽  
Stream Flows ◽  
Fluid Flow Velocity ◽  
Photoelectric Sensor ◽  
Velocity Measuring ◽  
Short Time

Automatic monitoring of hydrologic properties such as water velocity at short-time intervals is critical for understanding watershed eco-hydrological processes. This can also be used to study the laws of stream flows and interactions ecological process. The advent of modern electronic technology (and the near-perfection of especially sensor and data collection technologies), has made it possible to use automatic monitoring systems to continuously measure hydrologic properties at short-time intervals. This paper introduces one such paperless flow velocity measuring/recoding system. The system uses a photoelectric sensor that is mainly comprised of photoelectric velocity sensor and pulse recorder. The system uses propellers (with reflective panels and photoemission cells) to transform flow velocities into optical pulse signals. It also uses photosensitive tubes to transform optical pulse signals into electric pulse signals. The electric pulse counts (generated in unit time) are recorded via pulse recorders. This therefore accomplishes automatic monitoring and continuous recording of fluid flow velocity.

Ultrasonic Flow Velocity Sensor Based on Picosecond Timing System

1986 ◽  
Vol IE-33 (2) ◽  
pp. 162-165 ◽  
Author(s):  
Pradip K. Chande ◽  
P. C. Sharma
Keyword(s):  
Flow Velocity ◽  
Velocity Sensor ◽  
Timing System

scholarly journals A fiber-optic Doppler blood flow-velocity sensor

2017 ◽  
Vol 3 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Vitaliy I. Krasovskii ◽  
Ivan N. Feofanov ◽  
Pyotr I. Ivashkin ◽  
Mishik A. Kazaryan
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Fiber Optic ◽  
Velocity Sensor
Sign in / Sign up

Export Citation Format

Share Document