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Hydraulic engineering
Published in Mohammad Albaji, Introduction to Water Engineering, Hydrology, and Irrigation, 2022
Sediment transport is the movement of solid particles (sediment), typically due to a combination of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained. Sediment transport occurs in natural systems where the particles are clastic rocks (sand, gravel, boulders, etc.), mud, or clay; the fluid is air, water, or ice; and the force of gravity acts to move the particles along the sloping surface on which they are resting. Sediment transport due to fluid motion occurs in rivers, oceans, lakes, seas, and other bodies of water due to currents and tides. Transport is also caused by glaciers as they flow, and on terrestrial surfaces under the influence of wind. Sediment transport due only to gravity can occur on sloping surfaces in general, including hillslopes, scarps, cliffs, and the continental shelf – continental slope boundary (Figure 1.5).
Sediment Transport and Changes in the River Bottom Topology Downstream of the Jeziorsko Reservoir
Published in Saeid Eslamian, Faezeh Eslamian, Flood Handbook, 2022
Hämmerling Mateusz, Kałuża Tomasz, Zaborowski Stanisław
Influential parameters for sediment transport according to (Sinnakaudan et al., 2010) are dimensionless unit stream power, time rate of potential energy expenditure per unit weight in an alluvial channel, dimensionless flow depth (water depth ratio), relative roughness on bed, roughness on the bed, fall velocity Reynolds number, relative sediment particle size, flow parameter, ratio of shear velocity and fall velocity, dimensionless grain size, sediment mobility number, motion of near-bed particles, hiding-exposure function, particle densimetric Froude number for initiation of motion, and sheltering factor.
Coastal transport processes
Published in Dominic Reeve, Andrew Chadwick, Christopher Fleming, Coastal Engineering, 2018
Dominic Reeve, Andrew Chadwick, Christopher Fleming
In practice, virtually all sediment transport occurs either as bedload or as a combination of bedload and suspended load (suspended load rarely occurs in isolation, except for certain cases involving very fine silts). The combined load is known as a total load. It is possible to calculate the total load from the sum of the bedload and suspended load, as described in the preceding sections. However, this requires careful matching of the bed and suspended load transport equations at a well-defined height. Practically, it is very difficult to separate bed and suspended load. For this reason, some researchers have tackled directly the problem of total load. Some examples of total load formulae are now outlined.
Artificial intelligence models for suspended river sediment prediction: state-of-the art, modeling framework appraisal, and proposed future research directions
Published in Engineering Applications of Computational Fluid Mechanics, 2021
Hai Tao, Zainab S. Al-Khafaji, Chongchong Qi, Mohammad Zounemat-Kermani, Ozgur Kisi, Tiyasha Tiyasha, Kwok-Wing Chau, Vahid Nourani, Assefa M. Melesse, Mohamed Elhakeem, Aitazaz Ahsan Farooque, A. Pouyan Nejadhashemi, Khaled Mohamed Khedher, Omer A. Alawi, Ravinesh C. Deo, Shamsuddin Shahid, Vijay P. Singh, Zaher Mundher Yaseen
Accurate prediction of the amount of suspended sediment in rivers and streams is critically important for the operation of canals, diversions, and dams (i.e. hydraulic structures) (Cigizoglu, 2004; Liu, Zhou, et al., 2019; Sharafati et al., 2019; Suif et al., 2016). In watershed systems, sediment transport and erosion are a complex hydrological and environmental problems so the impact of sediments present in a river in terms of the global utilization of surface water resources has become a major research area (Greig et al., 2005; Malagó et al., 2017; Sinha et al., 2019). Several natural processes influence sediment dynamics in river basins, including deforestation, overgrazing, and agricultural activities that erode the soil surface and contribute much of the sediment input. Given the difficulty faced by physical-deterministic models (e.g. issues associated with initial or boundary conditions, stochasticity of river flow, and non-stationarity of the flow), the prediction of sediment load in a river is more likely to be achieved using AI-based modeling frameworks that are capable of handling nonlinear relationships between water flow and environmental factors.
Bedload transport: a walk between randomness and determinism. Part 1. The state of the art
Published in Journal of Hydraulic Research, 2020
Bedload transport is a specific form of sediment transport, which involves coarse particles (sand, gravel or coarser particles) rolling or saltating along the streambed. In Europe, the increased construction of navigation channels in the eighteenth century gave impetus to the creation of hydraulics – the science of water flow (Levi, 1995). The issue of bed erosion and stability had become progressively more problematic as more channels were built across Europe. The first qualitative description of the erosive action of rivers appeared in 1697 in the book “Della natura de' fiumi” (On the nature of rivers) by the Italian polymath, Doménico Guglielmini. Today it is largely forgotten, but its influence was significant in the eighteenth century (Simons & Şentük, 1992). At the end of the Little Ice Age, in the nineteenth century, many European countries faced major flooding. For the first time in European history, nationwide mitigation strategies based on river engineering and reforestation were implemented to control water flow on a large scale (Ford, 2016; Vischer, 2003). Rivers and mountain streams mobilizing coarse sediment posed their own specific problems, and these pushed engineers to make the distinction between bedload and suspension. Indeed, bedload transport theory appeared at that time, with the earliest quantitative formulation of a bedload equation usually being attributed to Paul du Boys, a young French engineer studying the Rhone (du Boys, 1879; Hager,2005, 2009).
Performance of blind detection frame work using energy detection approach for local sensing in intelligent networks
Published in International Journal of Computers and Applications, 2021
K. Venkata Vara Prasad, P. Trinatha Rao
A basic and generally accepted model for thermal noise in communication channels is the set of assumptions that the noise is additive, i.e. the received signal equals the transmit signal plus some noise, where the noise is statistically independent of the signal. The noise is white, i.e. the power spectral density is flat, so the autocorrelation of the noise in time domain is zero for any non-zero time offset. The noise samples have a Gaussian distribution [25]. The latest methods of moving object detection in video sequences are captured by a moving camera. Although many researches and excellent works have reviewed the methods of object detection and background subtraction for a fixed camera, there is no survey which presents a complete review of the existing different methods in the case of moving camera. Most methods in this field can be classified into four categories; modeling-based background subtraction, trajectory classification, low rank and sparse matrix decomposition, and object tracking [26]. The capacity of suspended sediment is an important phenomenon for the soil conservation structure. Sediment concentration is measured using sensors in a river reach. Sediment transport is basically of two forms, bed load and suspended load. The amount of load carried in suspension by a river mainly depends on the volume and velocity of the stream. Actual sedimentation patterns and depths are extremely difficult to evaluate [27]. The Industrial Internet of Things is growing fast. But the rapid growth of IIoT devices raises a number of security concerns because the IIoT device is weak in defending against malware, and the method of managing a large number of IIoT devices is awkward and inconvenient [28].