Mathematical modeling Fluid determination in River bed Trough (original) (raw)
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2013 IAHR World Congress, Chengdu, China, 2013
A three-dimensional numerical model was applied to study the bed morphology and bedload transport of the junction of Ara and Kurau rivers in Perak in Malaysia. SSIIM2 a 3D k-ɜ turbulence CFD model with an adaptive, non-orthogonal and unstructured grid has been used for modeling the hydrodynamic of confluence. The numerical model was tested against field data from Ara-Kurau confluence. Satisfactory agreement was found between computed and measured bedload and bed elevation in the field. The study indicates that numerical models might become a useful tool for predicting the bedload transport rate and bed morphology changes in river confluences.
Solutions of laminar mud flow on rectangular channel
Mudflow is a common phenomenon in mountainous area. A lot of researches had simulated debris flows with mudflow. However, either numerical analysis or approximate solutions needs a fundamental solution to work with. In the present paper, we focused on the analytical solutions of fluid mud by using the Bingham fluid model. By using the fact that boundary layer is thin, the solutions of steady uniform flow can be constructed on an inclined rectangular channel. The results can be expressed as function of depth ratio between shear layer to whole layer and Bingham number. The limiting cases for narrow channel and wide one can be discussed by changing the depth width ratio. The solutions on wide channel are the same as other research.
EFFECT OF BED ROUGHNESS ON FLOW CHARACTERISTICS
Resistance to flow determines several hydraulic parameters in streams and rivers that should be properly represented for estimating water discharges and sediments transport. In this research, a combination between experimental and numerical models study were carried out to investigate the influence of bed roughness of flow characteristics. Seventy two (72) runs were conducted physically and verified numerically. 6 bed materials were used (Gravel, Cement, Interlock, Grass, Formica, and Vegetations). 4 discharges and 3 tail gate water levels were tested with each bed material. Results were analyzed and were graphically presented and the percentages of errors between the obtained results from the used models were reported to define the sufficient compatibility between the used models. The Manning roughness coefficient was estimated for each bed material using the experimental and numerical models. The percentages of errors between them were reported and were under estimations. The models proved that for a given bed material, the roughness coefficient was inversely proportional to the discharge and directly proportional to the tail gate water levels.
CALCULATING BEDLOAD TRANSPORT IN RIVERS: CONCEPTS, CALCULUS ROUTINES AND APPLICATION
Revista Brasileira de Geomorfologia, 2019
Rivers are immensely important to human activities such as water supply, navigation, energy generation, and agriculture. They are also an important morphodynamic agent of erosion, transport and deposition. Their capacity to transport sediment depends on their hydraulic characteristics and can be predicted by mathematical models. Several mathematical models can be used to compute bed-load transport. Each one is appropriately better for certain conditions. In this paper, we present an application built in Microsoft Excel to compute the bed-load transport in rivers based on the Van Rijn mathematical model. The Van Rijn model is appropriate for rivers transporting sandy sediments in conditions of subcritical fl ow. Hydraulic parameters such as channel slope, stream power, and Reynolds and Froude numbers can be calculated using the application proposed here. The application was tested in the Paraná River and results from the calculations are consistent with data obtained from fi eldwork surveys. The error of the application was only 20%, which shows good agreement of the model with survey values.
Bed Load Transport Analysis for Gravel Bed River
GRD Journals, 2019
Prediction of bed load transport is important in many river engineering projects, including hydraulic structures like piers, reservoir life of dams, etc. The maximum bed load transport per unit width that a particular discharge can transport at a certain slope is defined as bed load transport rate. In the present study, analysis of steep slope river data is carried out using bed load functions of Parker (1979) Parker et.al (1982), Parker (1990),Graf (1998) and Wong and Parker (2006b).The computed dimensionless bed load transport rate are compared for analysing the prediction by selected equations. The predicted bed load transport rate is compared with the actual measured values for all data set to identify the equation which gives best prediction of bed load transport rate.