Artificial Flows Research Articles

Silala River Case: The Equitable Utilization Right and the Issues of Water Commodification and Artificial Flows

Silala River Case: The Equitable Utilization Right and the Issues of Water Commodification and Artificial Flows

Age- and Sex-Specific Nomographic CT Quantitative Plaque Data From a Large International Cohort

BackgroundWith growing adoption of coronary computed tomographic angiography (CTA), there is increasing evidence for and interest in the prognostic importance of atherosclerotic plaque volume. Manual tools for plaque segmentation are cumbersome, and their routine implementation in clinical practice is limited. ObjectivesThe aim of this study was to develop nomographic quantitative plaque values from a large consecutive multicenter cohort using coronary CTA. MethodsQuantitative assessment of total atherosclerotic plaque and plaque subtype volumes was performed in patients undergoing clinically indicated coronary CTA, using an Artificial Intelligence–Enabled Quantitative Coronary Plaque Analysis tool. ResultsA total of 11,808 patients were included in the analysis; their mean age was 62.7 ± 12.2 years, and 5,423 (45.9%) were women. The median total plaque volume was 223 mm3 (IQR: 29-614 mm3) and was significantly higher in male participants (360 mm3; IQR: 78-805 mm3) compared with female participants (108 mm3; IQR: 10-388 mm3) (P < 0.0001). Total plaque increased with age in both male and female patients. Younger patients exhibited a higher prevalence of noncalcified plaque. The distribution of total plaque volume and its components was reported in every decile by age group and sex. ConclusionsThe authors developed pragmatic age- and sex-stratified percentile nomograms for atherosclerotic plaque measures using findings from coronary CTA. The impact of age and sex on total plaque and its components should be considered in the risk-benefit analysis when treating patients. Artificial Intelligence–Enabled Quantitative Coronary Plaque Analysis work flows could provide context to better interpret coronary computed tomographic angiographic measures and could be integrated into clinical decision making.

OPTIMIST: Lightweight and Transparent IDS With Optimum Placement Strategy to Mitigate Mixed-Rate DDoS Attacks in IoT Networks

Distributed denial of service (DDoS) attacks are widespread for Internet of things (IoT) systems that aim to disrupt the availability of a system completely (high-rate DDoS) or partially (low-rate DDoS). Design and placement of Intrusion Detection Systems (IDS) for DDoS attacks on IoT systems are challenging due to the low power and lossy nature of networks. Existing IDSs are designed to handle either high-rate or low-rate DDoS but cannot handle both with good accuracy. Existing IDS placement techniques are mostly non-transparent, making malicious nodes aware of the presence of IDS nodes. Most of the IDS placement strategies are non-optimal, making them energy inefficient. Accordingly, this work proposes a transparent, optimally placed, distributed IDS solution, namely OPTIMIST, which can handle both high-rate and low-rate DDoS attacks with good accuracy. The placement problem is formulated as the weighted minimum vertex cover problem of a K-uniform hypergraph and solved with an approximation algorithm. The IDS module is based on a LSTM model where a novel offline training method for LSTM is proposed using WGAN-generated artificial flows. Extensive experimentation on simulation and testbed shows that the OPTIMIST can best achieve the balance between DDoS detection and energy overhead.

Importance of artificial high flows in maintaining the ecological integrity of a regulated river

Artificial high flows attempt to simulate natural flood pulses in flow-regulated rivers with the intent to improve their ecological integrity. The long-term use of such high flow events have shown beneficial ecological effects on various rivers globally. However, such responses are often non-linear and characterized by underlying feedback mechanisms among ecosystem components. The question arises as to what happens when such high flow releases are disrupted or even discontinued. Here, we used the long-term (22 years) monitoring dataset from the river Spöl to examine whether discontinuation (2016–2021) of the flood program (annual artificial high flows from 2000 to 2016) resulted in the ecological degradation of the river. We used monitoring data of physico-chemistry, periphyton, benthic organic matter, macroinvertebrates and fish (brown trout, Salmo trutta fario L.) in the analysis. The flood program had no long-term effect on water physico-chemistry with most parameters showing typical variations associated with season and inter-annual weather patterns. The floods were effective at mobilizing bed sediments that reduced periphyton biomass and benthic organic matter following each flood. Increases in periphyton biomass and benthic organic matter occurred between floods, but both parameters showed no significant increase with discontinuation of the flood program. Floods reduced macroinvertebrate densities, but with density increases occurring between floods. The pulsed disturbances, and the progressive change in the habitat template, resulted in shifts in community assembly by reducing densities of Gammarus fossarum, a dominant crustacean, which allowed other taxa to colonize the system. Macroinvertebrate densities remained low after discontinuation of the floods, although G. fossarum densities have increased substantially while other taxa, especially some stoneflies, remained low in abundance. Notably, community assembly returned to a pre-flood composition with discontinuation of the floods. The abundance of brown trout increased substantially during the flood program but returned to low pre-flood numbers with discontinuation of the floods. We conclude that the flood program was beneficial to the ecology of the river Spöl and discontinuation of the floods resulted in degradation of the system after a relatively short lag period. However, the system showed high resilience to an earlier perturbation, a sediment spill in 2013, suggesting a rapid positive response by biota with resumption of the flood program.

Level-Set Interface Description Approach for Thermal Phase Change of Nanofluids.

Simulations of thermally driven phase change phenomena of nanofluids are still in their infancy. Locating the gas–liquid interface location as precisely as possible is one of the primary problems in simulating such flows. The VOF method is the most applied interface description method in commercial and open-source CFD software to simulate nanofluids’ thermal phase change. Using the VOF method directs to inaccurate curvature calculation, which drives artificial flows (numerical non-physical velocities), especially in the vicinity of the gas–liquid interface. To recover accuracy in simulation results by VOF, a solver coupling VOF with the level-set interface description method can be used, in which the VOF is employed to capture the interface since it is a mass conserving method and the level-set is employed to calculate the curvature and physical quantities near the interface. We implemented the aforementioned coupled level-set and VOF (CLSVOF) method within the open-source OpenFOAM framework and conducted a comparative analysis between CLSVOF and VOF (the default interface capturing method) to demonstrate the CLSVOF method’s advantages and disadvantages in various phase change scenarios. Using experimental mathematical correlations from the literature, we consider the effect of nanoparticles on the base fluid. Results shows that the new inferred technique provides more precise curvature calculation and greater agreement between simulated and analytical/benchmark solutions, but at the expense of processing time.

Safe and effective methods for mining thin tilt and steeply dipping deposits with ore drawing via mud flow

For mining of thin (1&ndash;3m) tilt (15&ndash;45&deg;) ore bodies, it is recommended to use the mining method with induced mud&ndash;water&ndash;stone flows to deliver broken ore up-dip the bodies in combination with scraper handling of ore along the strike and water jet washing of ore when forming columnar pillars, including underhand ore cutting, with division of blocks into many long stopes along the block strike, heading of one or two tilted accumulation and haulage rooms to be close-looped with the long stopes, scraping of broken ore to the tilt accumulation and haulage rooms and mud flow of ore along these rooms. This method can increase the stoping capacity as per the number of stopes in a block: for example, in a 160 m wide, only two tilt rooms are required to be headed between levels. The artificial mud flows in mining (or re-mining) of thin and steeply dipping ore bodies which have their girtwise bottom boundary skewed at 15&ndash;45 &deg;, are no less effective. For the purpose of mining (re-mining) of such reserves, it is proposed to use a process flowsheet as follows: broken ore flows under gravity to the lower part of the extraction block and, then, along the tilted bottom of the block, it goes down under the action of gravity and energy of water flow in the mode of the mud&ndash;water&ndash;stone flow to the ore intake room on this level. In this case, as against mechanical haulage, the mud flow of broken ore essentially enhances the ore production output owing to the high capacity of the mud flow, and greatly reduces the scope of the preparatory and actual mining operations connected with the block bottom formation.The study was supported in the framework of the Target Financing Program of the Ministry of Education&nbsp;and Science of the Republic of Kazakhstan, Program No. 2018/ВR05236712.

Population genetic structure and conservation management of hill pigeons (Columba rupestris) recently endangered in South Korea

BackgroundHill pigeons (Columba rupestris) are close to local extinction (ca. less than 100 individuals) in South Korea where a variety of conservation management procedures are urgently required.ObjectiveThis study was aimed at determining the conservation direction of captive propagation and reintroduction of hill pigeons using genetic information based on mitochondrial DNA. We also evaluated the extent of hybridization between hill pigeons and cohabiting domestic pigeons.MethodsWe used 51 blood samples of hill pigeons from Goheung (GH), Gurye (GR), and Uiryeong (UR), and domestic pigeons cohabiting with hill pigeon populations. Genetic diversity, pairwise Fst, analysis of molecular variance, and haplotype network analysis were used to examine the genetic structure of hill pigeons.ResultsHill pigeons that inhabited South Korea were not genetically distinct from Mongolian and Russian populations and showed relatively low genetic diversity compared with other endangered species in Columbidae. The GR population that exhibited the largest population size showed lower genetic diversity, compared to the other populations, although the pairwise Fst values of the three populations indicated low genetic differentiation. The GH and GR populations were confirmed to lack hybridization, relatively, whereas the UR population was found to exhibit some degrees of hybridization.ConclusionTo conserve hill pigeons with low genetic diversity and differentiation in South Korea, the conservation process of captive propagation and reintroduction may require artificial gene flows among genetically verified populations in captivity and wildness. The introduction of foreign individuals from surrounding countries is also considered an alternative strategy for maintaining genetic diversity.

Tributary effects on the ecological responses of a regulated river to experimental floods

Rivers regulated by dams display several ecosystem alterations due to modified flow and sediment regimes. Downstream from a dam, ecosystem degradation occurs because of reduced disturbance, mostly derived from limitations on flow variability and sediment supply. In the last decade, most flow restoration/dam impact mitigation was oriented towards the development of environmental flows. Flow variability (and consequent disturbance) can be reintroduced by releasing artificial high flows (experimental floods). Flow-sediment interactions during experimental floods represent strong ecosystem drivers, influencing nutrient dynamics, and metabolic and functional properties. In river networks, sediment and water inputs from tributaries generate points of discontinuity that can drive major changes in environmental conditions, affecting habitat structure and determining functional differences between upstream and downstream. However, despite the relevance for management, flow/sediment relations during environmental flows − and more importantly during experimental floods − remain poorly understood, mostly due to the lack of empirical evidence. In this study, we examined how a major tributary (source of water and sediments) modified the physical habitat template of a regulated river, thereby influencing ecological and geomorphological responses to experimental floods. Methods combined high-resolution drone mapping techniques with a wide range of biological samples collected in field surveys before, during, and after experimental floods in an alpine river. Data were used to quantify changes in relevant functional and structural ecosystem properties, relating ecological responses to geomorphological dynamics. Results highlight the importance of tributaries in restoring ecosystem properties lost after damming, enhancing the resilience of the system. In addition, we observed that disturbance legacy played a fundamental role in determining ecological conditions of a river prior to experimental floods, thus confirming that considering flow variability and sediment availability is crucial in adaptive dam management and environmental flows design.

Subgrid surface connectivity for storm surge modeling

Subgrid modeling to account for unresolved topography within the context of shallow water equations relies on the use of coarse grids for computational efficiency. However, excessively coarse grids can lead to artificial cross flows between hydrologically disconnected areas separated by physical barriers smaller than the grid size. An approach based on introducing cell and edge clones, consisting of connected groups of pixels in each cell, is able to systematically remove such artificial cross flows. Such an approach considers that the subgrid barriers permanently divide flow among clones and effectively restrict flow to a predetermined path. In this work, a simple algorithm, along with the use of an overtopping formula, is proposed to extend the clone approach to a scenario in which clones are allowed to be further split and merged as needed, depending on the surface elevation during a given runtime. The algorithm is intended for accommodating the possibility of the subgrid barriers being inundated and no-longer dividing the flow during an extreme event. The performance of the proposed algorithm is demonstrated through a series of idealized and more realistic test cases, showing considerable improvements over existing methodologies.

The importance of the hydrological pathways in exporting nitrogen from grazed artificially drained land

When considering hydrological export pathways from drained pastoral fields, the shallow groundwater underlying the artificial drainage system may fulfil an as important role as the artificial drainage system itself. However, the important split between artificial drainage and groundwater flows at a field site is usually unknown. Consequently, the effects that the groundwater system’s redox status may have on the forms and total amounts of nitrogen (N) exported from the site cannot be confidently assessed. We addressed these deficiencies by investigating the export of various forms of N in the artificial drainage and the shallow groundwater beneath two dairy farming sites (Tatuanui, Waharoa) within the Piako River catchment in New Zealand.Due to the very low hydraulic conductivity of the degraded peat in the saturated zone perched on a clay aquiclude, no significant water or contaminants were exported at Tatuanui via the unconfined shallow groundwater. Accordingly, artificial drainage discharge into the receiving surface collector drain was the only export pathway for N at this site. The sealed nature of the groundwater zone resulted in the accumulation of organic-N and ammonium-N in the peaty shallow saturated zone underlying the mineral soil. In contrast, the Waharoa site featured a more mobile shallow groundwater system, which on average conveyed approximately equal volumes of water offsite as the artificial drainage system.Nitrate (NO3-N) was at both sites the predominant form of N (76%) leached from the aerobic soil profile and discharged through the artificial drainage. As the shallow groundwater was at both sites in a reduced redox state, any NO3-N leached from the rootzone into the saturated zone was consumed. Accordingly, even the mobile shallow groundwater at Waharoa did not convey significant NO3-N. The NO3-N consumption in the reduced groundwater presumably occurred due to dissimilatory NO3-N reduction (concomitant increases in ammonium-N concentrations, with no organic material available for mineralisation in the saturated zone) and microbial denitrification (producing gaseous forms of N). The NO3-N reductions in the groundwater resulted in the average total N exports via the shallow groundwater pathway at the Waharoa site being substantially lower (31% of the exported N) than in the artificial drainage (69%). This is despite both pathways exporting similar water volumes. Because of the NO3-N consumption in the reduced shallow groundwater at Waharoa, over 98% of the N exported through this pathway was either as ammonium-N or organic-N.

Response of the Dnieper river fluvial system to the river erosion caused by the operation of the Kaniv hydro-electric power plant (Ukraine)

The commission of the Kaniv dam in 1973, as the last of the six dams on the lower Dnieper River cascade, changed the river regime completely. A description of these changes and their impact on the evolution of the fluvial anastomosing system form the aims of the study. The operation of the hydroelectric power plant (HPP) in Kaniv significantly affected the erosion and accumulation of sediment on valley floor and thus changed the fluvial system of the Dnieper River below the dam. The HPP initially operated on a hydropeaking system (until the early 1990s) and then on a run-of-river system. This study used the indicators of hydrologic alteration (IHA), the RB flashiness index, archival topographic and bathymetric maps, hydrological and sedimentological field studies, and satellite images to assess how the magnitude and duration of changes in the flow regime affected erosion and accumulation processes on the river bed and changed the pattern of channels as well as the landforms separating them.Until the commission of the dam in Kaniv, the fluvial system of the Dnieper River in its undisturbed state was a sand-bed channel but was then transformed from a braiding to an anastomosing river system. This was achieved by bars where consolidation of vegetation on fine clastic deposits created interchannel areas and islands. During the operation of the hydropeaking system, characterised by frequent artificial flows of short duration, channels became incised and narrowed. Interchannel areas were divided up into islands. Then, after the HPP switched to working a run-of-river system, the islands began to merge again into interchannel areas. This happened as a result of intensified erosion processes in both the main and the side channels. The operation of the HPP, by changing the flow regime and sedimentation processes in the river valley, modified the natural process of evolution of the fluvial system of the Dnieper River.

Роль процесса глобализации в становлении цифровой экономики

The article highlights and analyzes the preconditions and main aspects of the formation of digital globalization, including the achievements of the fourth industrial revolution, artificial intelligence technologies, global data and information flows, digital platforms and e-commerce. While financial flows and traditional trade in goods at the global level are declining due to the worldwide COVID-19 pandemic, global digital economic ties, on the contrary, are expanding significantly.

Flow field calibration of a newly developed Laval nozzle in 2.4m transonic wind tunnel

The range of Mach number of 1.3 to 1.5 is defined as low-supersonic flow in wind tunnel testing, which is necessary range for major fighters, aerospace vehicles, and missiles to reach the cruise state. It is also the most difficult test range for conventional ground simulation equipment due to sound barrier and uniformity of artificial air flows. In order to expand the test range of 2.4m transonic wind tunnel, researches on low supersonic flow filed calibration was carried out, and the geometrical parameters of perforated walls in test section were determined. Measured results of flow uniformity are compared with advanced wind tunnels using cross-shaped rake and cone-cylinder model. The results show that uniformed low supersonic flow in model testing area was obtained using newly developed nozzle together with perforated walls in 2.4m transonic wind tunnel, which effectively improve the simulation capability of the facility. Together with the capacity of 2m supersonic wind tunnel, seamless link of test data has been achieved in high speed regime, which has formed an integrated test platform for sub-, trans-, and supersonic speeds on the order of 2 meters.

The Response of River‐Resident Fish to Reservoir Freshet Releases of Varying Profiles Intended to Facilitate a Spawning Migration

AbstractNatural hydrological regimes encompass varying seasonal flow characteristics that provide fish with cues and opportunities for upstream spawning migrations, but these flows are often modified/absent in regulated rivers. Compensatory artificial flows (freshets) can be released from reservoirs to replicate these characteristics, but studies testing their effectiveness are limited. To address this, river‐resident brown trout, a species known to undertake spawning migrations, were manually tracked using radio telemetry in a regulated upland river in northern England in response to 11 freshet releases of differing timing, magnitude, and duration. Spawning migrations were not observed because extent of movement during freshets was generally small and the pattern of movement (i.e., directionality and relocation indices) was comparable between impact/control reaches. Movements during freshets were comparable with those observed the days immediately before/after and were small relative to the entire tracking period. In conclusion, freshet characteristic of those recommended to produce “naturalized” autumn/winter flow elevations did not stimulate/facilitate spawning migrations of river‐resident brown trout under the given seasonal conditions. Outside freshets, longer unidirectional movements occurred during low‐flow periods and elevated river level due to rainfall, including during periods of reservoir overtopping. Notwithstanding, fish in experimental reaches were significantly more active (total distance moved) and occupied a larger extent of river (range during freshet) than those in control reaches during short‐duration freshets. Therefore, during dry years/when (autumn/winter) reservoir overtopping events are unlikely, small‐magnitude freshets providing flows that allow fish short opportunities to search for/find superior local habitat while minimizing total water released are recommended.

Limited impacts of experimental flow releases on water quality and macroinvertebrate community composition in an upland regulated river

AbstractRiver regulation following the construction of dams has affected the hydrology, water quality, and biology of watercourses across the globe. The term “environmental flows” has been used to describe measures that can be employed to return some lost elements of the natural flow regime. Their introduction has been suggested as a way to mitigate the impacts of river regulation throughout the world, but understanding of the effects of artificial high flows on water quality and biota is limited for many different river types. We report a field study that manipulated compensation flows from reservoirs in the Pennine uplands of northern England and measured changes in water quality and benthic macroinvertebrates using a before‐after‐control‐impact approach. These resulted in minor short‐term changes in water quality, but there was no evidence of immediate (within 48 hr) responses by the macroinvertebrate community to individual flow releases. However, a shift in macroinvertebrate community composition was found after multiple releases, characterized by reductions in Amphinemura sulcicollis (Plecoptera) and Baetis rhodani (Ephemeroptera) and changes in the density of all Diptera. The introduction of short‐term flow pulses in flashy regulated river systems is unlikely to yield significant changes in water quality and biota. Nevertheless, cumulative rather than single environmental flow events show promise for mitigating some of the impacts of river regulation. More widely, our findings indicate that environmental flow releases from reservoirs may have to go beyond occasional experimental high flow releases if these rivers are to more closely mimic unregulated river systems.

Attraction of migrating glass eel (Anguilla anguilla) by freshwater flows from water pumping stations in an urbanized delta system

Most studies on glass eel (Anguilla anguilla) migration are performed in natural estuaries, where they enter freshwater systems to live there for a period of years before they swim back again to the sea to reproduce. In these natural systems, river flows play a major role in attracting and directing migrating eels. However, coastal areas get urbanized more and more and characterized by anthropogenic barriers and hampered or artificial water flows. The effects of these flows on glass eel migration are poorly understood. Therefore, in this study glass eel were sampled at water pumping stations in a constructed part of the Rhine delta in the Netherlands. A mixed linear-effect model was used to determine effects of freshwater flows from water pumping stations on glass eel catch. We found that freshwater flows from water pumping stations had a significant but small effect on glass eel catch. Pumping activity had no significant effect on glass eel catch at sample locations with a continuous freshwater flow from fish passages. However, a low predictive value of the model and low numbers of individuals per sample prohibited strong conclusions on effects of anthropogenic freshwater flows on glass eel migration. More individual tracking techniques should be used to improve understanding migratory behavior of glass eel.

A continuous finite element solution of fluid interface propagation for emergence of cavities and geysering

A finite element method integrated with flux correction techniques is presented for the solution of two nearly incompressible fluids flow with moving interfaces. The procedure incorporates the advection of a phase function to couple fluids motion and the contact discontinuity, and a modified continuity equation preserving mass conservation by considering the parametric definition of density. Limiting bounds comprise information of interface location, improving responses for flows with low density ratio between fluids. A simple conservative postprocessing restores interface resolution by means of an anisotropic streamlined diffusion equation. Strategies to decrease transition thickness between two fluids are examined, using as background the stability of artificial stratified flows and mass error estimation due to density interpolation. To decrease transition thickness, a novel inexpensive nested-grid refinement is proposed. The method is founded in flux-correction principles, ensuring conservation and monotonicity of the variables during dynamical adaptation. Numerical experiments explore the efficacy of the procedure for demanding tests of phase transport and of the equations of motion for interface problems. The main target of this work is to model the genesis and propagation of air cavities in water pipe flows, thus a substantial part of testing focuses on these challenging phenomena. Weakly compressible fluid assumption is essential for proper momentum transfer between phases in the aforementioned dynamics, particularly for bubble rising process. An axisymmetric solution is also developed as an alternative cost-effective choice of the full three-dimensional model for flows in circular ducts.

How to allocate interbasin water resources? A method based on water flow in water-deficient areas

Water resources are one of the most important natural resources in ecosystems, and they have characteristics of natural and artificial flows. Natural flow causes water resources to flow from upstream to downstream between different regions in accordance with the terrain, whereas artificial flow leads to changes in seasonal and regional allocations of water resources. The water safety status of different regions differs under natural water flow, while water-deficient areas can restore the regional water safety situation by artificially allocating water resources. This study (1) uses Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) software to simulate water provisions and calculates water consumption through industrial, agricultural and domestic water use; (2) combines the digital elevation model (DEM) of Shandong and Henan Provinces and uses computer programming to introduce natural flow into water resource assessment; (3) according to the flow relationship between cities, assesses water resource security in real conditions; and (4) based on the water security index (WSI), simulates the water resources of interbasin water transfer. The results show that the water safety situation of cities in Shandong and Henan Provinces is very poor. Only 1 city is safe with regard to water resources out of 34 cities in the 2 provinces, while the other 33 cities are unsafe. The eastern coastal area of Shandong Province has the largest demand for water resources, of which Yantai City, with the worst water security situation and the water resources allocation, has a demand of 8.53 × 108 m3. The results for Xinyang, which has the best water security situation, indicate that water resources should not be allocated artificially. The characteristics of water resource flow determine the necessity of considering the flow in regional water resource security assessment. A flow-based interbasin water transfer allocation scheme can provide a reference for relevant research.

Kinematic Storage Model (KSM) for Groundwater Development in Highly Permeable Hill Slope-Laboratory Study

Study of the groundwater table development and runoff generation is one of the most important parts of hydrology to develop a clear concept, especially in hill slope. The study is more complex in the real field rather than in the artificial system. The result in artificial systems developed and experimental observations may give good results. So, therefore, this study is aimed at modeling in the laboratory as artificial hill slope flows which include saturation excess surface runoff flows. The physical processes along with runoff generation depend on the factors—soil type, characteristic slope geometry, and initial soil conditions at the commencement of rainfall. The mechanisms involved in runoff formation process have been simulated successfully to compute hydrograph for hilly terrain and groundwater table development in highly permeable soil tested by kinematic storage model theory. The model represents the hill slope as a rectangular storage element of length 2.02 m, depth 0.15 m and width 1m With an impermeable bed making an angle of 10 degrees with the horizontal. The storage element is composed of two moisture zones: an unsaturated zone and a saturated zone. The result obtained is seemed good adjustment to the theory of hill slope model given by Nm Shakya, 1995. Aslo, the moisture profile variation in mixed sand profile was found immediately after the rainfall event. The result obtained shows that the timing and distribution of moisture over the depth where the maximum moisture content is 0.4 in mid of the depth which is more than in surface having a moisture level of 0.37.

Applicability of Acoustic Concentration Measurements in Suspensions of Artificial and Natural Sediments Using an Acoustic Doppler Velocimeter

For the investigation of turbulence and particles, interaction measurement systems are required, which are able to measure velocity and concentration fluctuations simultaneously. Acoustic Doppler Velocimeters (ADV) are widely used for velocity and turbulence measurements in natural and artificial flows. Based on the acoustic sonar theory, a model is presented that correlates the ADV’s Signal-to-Noise Ratio (SNR) and the suspended solids concentration of several natural (Ems Estuary, Lake Eixendorf, Lake Altmühl) and artificial sediments (Chinafill, quartz powder, bentonite, metakaolin) for the range 0.001 g/L–50 g/L. Within the presented method, the sound absorption in water and on particles is considered in a continuous approach for sampling frequencies up to 100 Hz. The widely-used log-linear relation between the SNR and the concentration, which is only valid for low concentrations, was extended for the high concentration regime. Measurement results show a similar behavior of the SNR with respect to varying suspended solid concentrations for different sediments. However, the analysis of the fit parameters shows systematic differences depending on the type of sediment. It is concluded that the proposed model is applicable as well for laboratory use as for measurements in rivers and estuaries. Finally, we discuss the reliability of the results and the methodology with regard to measurements in rivers, lakes, and estuaries.