Water Current Meter Research Articles

An Edge Computing Application of Fundamental Frequency Extraction for Ocean Currents and Waves.

This paper describes the design and optimization of a smart algorithm based on artificial intelligence to increase the accuracy of an ocean water current meter. The main purpose of water current meters is to obtain the fundamental frequency of the ocean waves and currents. The limiting factor in those underwater applications is power consumption and that is the reason to use only ultra-low power microcontrollers. On the other hand, nowadays extraction algorithms assume that the processed signal is defined in a fixed bandwidth. In our approach, belonging to the edge computing research area, we use a deep neural network to determine the narrow bandwidth for filtering the fundamental frequency of the ocean waves and currents on board instruments. The proposed solution is implemented on an 8 MHz ARM Cortex-M0+ microcontroller without a floating point unit requiring only 9.54 ms in the worst case based on a deep neural network solution. Compared to a greedy algorithm in terms of computational effort, our worst-case approach is 1.81 times faster than a fast Fourier transform with a length of 32 samples. The proposed solution is 2.33 times better when an artificial neural network approach is adopted.

Identification of prime factors of active river bank erosion in the lower course of Ganga Bhagirathi River: a study

The present study aims to identify prime factors of active and continuous riverbank erosion. Field visits were conducted from 2015 to 2019. To fulfil the objective of the study, 21 study units prone to bank erosion were selected along the banks of Ganga-Bhagirathi at Jangipur sub-division. Remote sensing and geographic information system were used to measure the area under erosion and deposition from the 1985 to 2015 at five-year intervals. Bank height, bank angle, length of fracture from bank line, river velocity, and channel depth were measured for each study unit using different instruments like cup-type water current meter, clinometers, and measuring tape. Soil samples were collected for textural analysis. Factor analysis was performed to find out prime responsible factors for active riverbank erosion. The result of the study shows that bank height, bank angle, channel width, and fracture length together comprise the first component, which explains 29.48 percent of variance. Riverbank erosion happens due to physical and manmade factors in the lower plain area of the Ganga-Bhagirathi River.

Information support for the procedure of measuring the flow rate of water in open channels by a water current meter with Arduino Micro board

The modernization of a typical water current meter is proposed to facilitate hydrological observations on natural and artificial open watercourses. An Arduino Pro Micro microcontroller board was used to read the speed of the current meter and primary data processing, programs were developed: for the lower level - a microcontroller located on the board, and for the upper level - a smartphone to determine the water speed. The programs take into account the peculiarities of converting data on the flow rate of water with a current meter and allow you to enter additional indicators that reduce the uncertainty of the results.

Development and Testing of Infrared Water Current Meter

Continuous monitoring of the river flow is essential for assessing water availability. River flow velocity is crucial to simulate discharge hydrographs of water in the hydrological system.This study developed a digital water current meter with infrared. The infrared current meter was tested using Ebonyi River at Obollo-Etiti and the test was performed at three different verticals (A, B, & C) across the watercourse of Ebonyi River. At each location, the velocity readings were taken at the 0.6 of the depth below the surface. The total depth of water at locations A, B, and C are 0.35m, 0.4m and 0.54m respectively. The digital water current meter with infrared display velocity readings obtained per second. To confirm the accuracy of the infrared current meter, it was tested alongside with a conventional water current meter. The measurements performed with the infrared current meter compared well with the measurement performed with conventional current meters. The linear regression equation for the measurements obtained using the two current meters was obtained.http://dx.doi.org/10.4314/njt.v33i2.8

Contaminated Sediment Management by Capping and Deep Water Confined Aquatic Disposal in the Harbor of Oslo

Abstract Dredging has been prohibited in the harbor of Oslo in the past 15 years as a result of serious sediment contamination. Through a joint effort of the Oslo Harbor Authorities, the Norwegian Road Administration, and the Norwegian Pollution Control Authorities, a remediation plan for the redevelopment of the old harbor of Oslo has been implemented. The plan, which will be completed in 2009, includes dredging of the shallow parts of the harbor down to 15 m of water depth (approximately 450,000 m3), capping of the deeper parts of the harbor (1,000,000 m2), as well as construction of a deep water confined aquatic disposal facility for the dredged material at 70-m depth in the inner Oslofjord. To prevent uncontrolled contaminant transport, an on-line monitoring system is operated that consists of buoys with turbidity loggers and a water current velocity meter. Passive samplers are used for time-integrated sampling of organic contaminants. In addition, periodic sampling and analysis of water and suspended solid samples are carried out. To document the environmental benefit from the remediation, contaminant transport is quantified before, during, and after remediation using flux measurements based on in situ diffusion chambers. Monitoring results show that remobilization of contaminants has been very limited and do not exceed the amounts defined in the environmental permit from the pollution control authorities (environmental budget). Capping resulted in more than 90 % reduction in contaminant flux.

Variation of the tidal properties around Gran Canaria

Analysis of water level and current meter series from different locations on the island shelf of Gran Canaria reveals strong variations in tidal properties. Semidiurnal sea level amplitudes agree with the results obtained from global tidal models for this region only on the northern coast of the island, while they decrease towards the southwest (10 cm difference for the M 2 constituent). Semidiurnal currents present maxima at the southeastern and northwestern extremities of the island (30–40 cm s −1 for M 2) and minima in the north-northeast and southwest (3–6 cm s −1 for M 2), showing simultaneous strong changes in the phase. Diurnal levels and currents display smaller variations than the semidiurnal band. The behaviour of semidiurnal constituents is studied with the help of analytical and numerical solutions, in which the incident wave is modelled by a barotropic M 2 Kelvin wave. The results show that the insular shelf could be a source of differences in level amplitudes around the island and could be also responsible for the enhancement of currents in the southeast and northwest. They also show that the variation of the current phases is due to the amplification of the standing character of the wave at the northeastern and southwestern parts of the shelf.

A numerical model for the winter circulation in Lake Trichonis, Greece

Progress in the understanding and eventual management of lakes depends upon iterative interactions between model-guided measurements and measurement-tested model development. A research example of this progress can be demonstrated by the measurement campaigns that were mounted in Lake Trichonis, in central Greece. Numerical simulations and analytical theories have been tested against currents, surface seiche and temperatures. Simultaneous water gauges, current meters, anemometric stations, thermometers, sediment and water samplers were used for the verification of the model. The agreement between the theoretically predicted and experimentally determined data was satisfactory for most of the verifications. The most significant error was due to atmospheric pressure. The computed surface seiche showed excellent agreement with the observations, even in spectral analysis. The computed currents showed circulation patterns very similar to those measured in the field. The computed temperature distributions throughout the lake were not in good agreement because of incoming water from the bottom.

External gravity oscillations in Lake Onega

Abstract. Lake Onega is located in the southern part of Karelia, in the north-west of Russia. We report data taken by various limnigraphs and current meters and isolate, by spectral analysis, the most conspicuous barotropic periods of these signals. The analysis that follows is based on the linearized shallow-water equations, that are solved for the free oscillations and thus identify the eigenperiods and corresponding mode structures for this lake. Computational results are presented for a finite difference representation for these surface-seiche equations applied to the entire Lake Onega including its bays. The grid consists of quadratic elements of 1000 m side length corresponding to 9344 active cells. The emerging matrix eigenvalue problem exceeds the storage and compuational capacity of standard PCs or workstations and thus requires use of the approximate Lanczos procedure to isolate the first ten eigenperiods and corresponding mode structures of the barotropic seiches, lying between 12.1 and 2.2 h. Comparison of computational results and inferences from the water level and current-meter records, disclose satisfactory agreement between theory and observation.

Hydrography and its effect on fish larvae in the Mauritanian upwelling area

During Meteor cruise 44 in January and February 1977 simultaneous hydrographical and biological investigations were carried out in the Mauritanian upwelling area . Both horizontally and vertically the hydrographic structure and fish larvae abundance were similar, apparently results of upwelling. Highest concentrations of fish larvae were found above the slope and above the outer shelf in aged upwelled water, whilst fresh upwelling water was free of larvae. The inshore boundary of fish larvae followed approximately the 16° C isotherm.Both hydrography and fish larvae populations at a given location varied in time, consequences of advection. A spatial and temporal investigation of species composition indicated that during upwelling fish larvae were carried from depths of about 30 m at the outer shelf towards the shore and northward. This pathway was also indicated by water mass analysis and current meter measurements.Within the upper 60 m the northward flow, however, decreased with increasing latitude. According to water mass analysis and species distribution there was no northward transport in the Cape Blanc area of epipelagic fish larvae, the major group within the ichthyoplankton.

Turbulence Measurement Study

The capability of a modified commercially available electromagnetic water current meter was evaluated for measurement of parameters necessary to quantify turbulent flow. Values of turbulence intensity were measured, and Fourier analyses of their oscillograph recordings were performed to obtain the spectral distribution of the energy. Field tests were then conducted at three locations selected on the basis of their differences in flow regime. The results showed that values of turbulent intensity for flows between very high to light turbulence levels ranged from 0.71 to 0.06, respectively, and the Fourier analysis of the data shows the energy to be concentrated generally below 5 Hz. This instrument can be used to obtain relative values of turbulent intensity and spectral information from field measurement.

Water Current Meter of Thermal Conductivity Type

Water Current Meter of Thermal Conductivity Type

Drag force water current meter for mean or steady flow measurement

A drag force water-flow meter is described for use in the nearshore zone which is cheap, reasonably accurate and of a simple and robust construction. A buoy-mounted monitoring device provides a semi-continuous recording capability which allows unattended data collection for up to ten days. The data may be automatically reduced to force vectors which are closely related to current speed. The instrument system has proved useful when measurement of nearshore mean water flow in the range 7–200 cm/s is required and the flow is fairly steady.

Water Current Meters in the Smithsonian Collections of the National Museum of History and Technology

Water Current Meters in the Smithsonian Collections of the National Museum of History and Technology

Water Current Meters in the Smithsonian Collections of the National Museum of History and Technology

Water Current Meters in the Smithsonian Collections of the National Museum of History and Technology

Closure to “Dr. Santorio's Water Current Meter, CIRCA 1610”

Closure to “Dr. Santorio's Water Current Meter, CIRCA 1610”

Closure to “Dr. Santorio's Water Current Meter, CIRCA 1610”

Closure to “Dr. Santorio's Water Current Meter, CIRCA 1610”

WATER CURRENT METER FOR MEAN FLOW MEASUREMENTS

A drag-sphere water current meter with a 0 to 6 ft/sec range has been developed for velocity measurements of relatively steady flows A two-component strain-gage type force transducer is mounted within a 3 7-inch-diameter perforated drag sphere Drag force measurements are related to the flow velocity around the meter Several drag sphere configurations were tested in selecting the 336-hole pattern Frequency response data have been recorded and evaluation tests were made with current meters deployed in an estuary Use of these current meters in studies of steady-state fluid processes and sediment responses is feasible They are simple, relatively inexpensive, and well suited to applications where several simultaneous measurements are needed to determine velocity profiles or map flow distributions.

Discussion of “Dr. Santorio's Water Current Meter, Circa 1610”

Discussion of “Dr. Santorio's Water Current Meter, Circa 1610”

Robert Hooke's Water Current Meter, Circa 1663

A water current meter is shown to have been built in 1663 by Robert Hooke (1635 - 1703), the author of Hooke’s Law of Elasticity, and the first Curator of Experiments at the Royal Society of London. No drawing of that meter is known to exist, but the type of rotor and the revolution-counting facilities that Hooke had used thereon were the same as he had shown in a drawing of one of his deep sea sounding devices. A reproduction of that drawing is presented in the article. This is the earliest current meter to have been found so far in which use has been made (as in modern current meters) of a freely-rotating sensor with facilities for observing the number of turns the sensor made within a measured period of time. Features of the current meter built by Reinhard Woltman in about 1790, are so similar to those of Hooke’s meter, that it is suggested that Woltman had duplicated Hooke’s meter. Several other velocity-measuring devices conceived between the times of Hooke (1663) and Woltman (1790) are described briefly.

Dr. Santorio's Water Current Meter, Circa 1610

A water current meter, and a similarly-constructed anemometer are shown to have been made in about 1610 by an Italian physician, Dr. Santorio Santorio, (1561-1636). It is contended that current meters (in contrast to ordinary floats) had been under consideration for over 100 years before the advent of either Pitot or Woltman (who are usually credited for having originally introduced such an innovation). A suggestion is offered that the development work on current meters during those intervening years might be an interesting subject for further research. Dr. Santorio made these instruments for determining the critical velocity conditions below which the noise of blusterous winds and a tumultuous waterfall tended to soothe, and above which it tended to disturb his patients in a certain area in Croatia (now Yugoslavia). Illustrations of those instruments, as drawn by Dr. Santorio, are presented.