Numerical Investigation of Temporal Variation of Density Flow and Parameters

Experimental investigations and observations indicate that water quality modeling is related to the formation of flows in the dam reservoirs. Correct estimation of dam reservoir flow, plunging point and plunging depth are very important for the dam reservoir sedimentation and water quality problem. Therefore, inflow river-water into a dam is modeled in two dimensions through a reservoir with sloping bottom. The model is developed using nonlinear and unsteady continuity, momentum, energy and k-ε turbulence model equations. The equations of the model are solved based on the initial and boundary conditions of the dam reservoir flow for a range of bottom slopes. In addition to velocity, temperature and turbulence viscosity variation through the dam reservoir, the effects of density flow parameters such as plunging depths, plunging points, mixing rate are determined from the simulation results. The results of the present model are compared to the previous experimental works and the mathematical models

Investigation of density plunging reservoir flow using mathematical modelling

Baraj haznesine giren su ile haznedeki su arasındaki yoğunluk farkı, sıcaklık farklılığından yada askı maddesi veya çözülmüş madde konsantrasyonu farklılığından oluşabilir. Bu çalışmada, sadece sıcaklık farklılığından oluşan yoğunluk akımları, tabanı eğimli bir hazne boyunca, iki boyutlu matematik model kullanılarak incelenmiştir. Kararsız akım durumunda, süreklilik, hareket, enerji, ve türbülans model denklemleri kartezyen koordinat sisteminde çıkarılmıştır. Bu denklemler hazne akımının başlangıç ve sınır şartları için çözülmüştür.Akım alanında oluşan hızlar, sıcaklıklar, karışım oranları, dalma noktaları ve dalma derinlikleri, kontrol hacim kavramı ve sonlu farklar metodu kullanılarak Fluent 5.3 programı ile belirlenmiştir. Sonuçlar daha önce yapılan matematik model sonuçları ve deney ölçmeleri ile karşılaştırılmış ve grafikler halinde boyutsuz olarak değerlendirtmiştir.Anahtar Kelimeler: Baraj hazne akımı, dalmış akım, coriolis etkisi, matematik model.                                 Density difference between inflowing and ambient waters may be due to a difference in temperature or concentration of dissolved or suspended substance. In this study, density flow, which will be occurring only due to a difference in temperature in a reservoir with a bottom slope is investigated by using two dimensional mathematical model. In the present model, nonlinear and unsteady continuity, momentum, energy and turbulence model equations are formulated in Cartesian coordinates. For the turbulence viscosity, k-? turbulence model is used with an extension to include production or destruction of turbulent kinetic energy.   The equations of the model are solved based on the initial and boundary conditions of the dam reservoir flow for a range of bottom slopes. Understanding of these flows is important from the point of view of water quality modeling, reservoir sedimentation studies, effluent mixing analyses and habitat in reservoirs. Velocities, temperatures, mixing rates as well as plunging points and plunging depths are determined using control volume concept and finite difference method using Fluent 5.3 software program. The results are compared with those of previous mathematical and experimental studies, and evaluated graphically in non-dimensional form.Keywords: Dam reservoir flow, plunging flow, coriolis effect, mathematical model

Flood Modeling Based on The Precipitation Data by Using Hec-Ras Software Version (5.0.7).

Floods are one of the most destroyable disasters that affect human life directly. It is important to model floods for the determination of the vulnerable areas, and planning of the dangerous zones. For this purpose, HEC-RAS software is in use to create complex flood models. In general, for the modeling of a flood by using any software, an accurate topography of the area, boundary conditions, Manning coefficients, and the flow data are essential. However, it is not always possible to have the flow rate of all streams located in the study area. Because of the mentioned reason, in this study authors preferred to directly use precipitation data for modeling the flood. A model was created by using SRTM satellite data for the digital elevation model. A two-dimensional geometry was created, and the precipitation data was added to the model. The main output of the performed model showed that using precipitation data directly on a flood model is not fully representative of the extent of flooding. According to the model result, the flood is spread over a wider area than it actually was

River Sediment Amounts Prediction with Regression and Support Vector Machine Methods.

Accurate estimation of the amount of sediment in rivers; determination of pollution, river transport, determination of dam life, etc. matters are very important. In this study, sediment estimation in the river was made using Interaction Regression (IR), Pure-Quadratic Regression (PQR) and Support Vector machine (SVM) methods. The observation station on the Patapsco River near Catonsville was chosen as the study area. Prediction model was developed by using daily flow and turbidity data between 2015- 2018 as input parameters. Models were compared to each other according to three statistical criteria, namely, root mean square errors (RMSE), mean absolute relative error (MAE) and determination coefficient (R2 ). These criteria were used to evaluate the performance of the models. When the model results were compared with each other, it was seen that the IR model gave results consistent with the actual measurement results

Forecasting of Suspended Sediment in Rivers Using Artificial Neural Networks Approach

Suspended sediment estimation is important to the water resources management and water quality problem. In this article, artificial neural networks (ANN), M5tree (M5T) approaches and statistical approaches such as Multiple Linear Regression (MLR), Sediment Rating Curves (SRC) are used for estimation daily suspended sediment concentration from daily temperature of water and streamflow in river. These daily datas were measured at Iowa station in US. These prediction aproaches are compared to each other according to three statistical criteria, namely, mean square errors (MSE), mean absolute relative error (MAE) and correlation coefficient (R). When the results are compared ANN approach have better forecasts suspended sediment than the other estimation methods

Numerical Modeling of Submerged Vane Flow

Scours in rivers occur due to high flow velocities. In order to reduce scour, flow velocities need to be reduced. Submerged vane structures are effective in both reducing the flow rate and directing the flow. In this study, numerical modeling was made with submerged vane structures. Models of the measured flow velocities in the channel, where submerged vane experiments were performed before, were compared with the results of the submerged vane experiment by using the 3-dimensional computational fluid dynamics (CFD) method. In the present CFD model, continuity and momentum, turbulence model equations are applied. For the turbulence viscosity, k-ε turbulence model is used. The results of the present model are compared with the previous experimental work

Numerical Analysis of the Flow Over the Dam Spillway

The determination of hydraulic parameters is very important in the design of the dam spillway structure. Hydraulic parameters are obtained by theoretical and empirical approaches according to the design flow discharge. In general, before the application project, tests are made on the hydraulic model and the design is given its final shape. Advanced numerical modeling techniques can be used in conjunction with or as an alternative to experimental studies. This study investigated hydraulic parameters in three dimensions under design flow in a dam spillway using computational fluid dynamics (CFD). In the numerical model, the VOF method, which can solve two-phase flows, and the standard k-e turbulence model are used. Obtained results were compared with experimental results. It was determined that the experimental and numerical model results were quite compatible with each other

Baraj hacmi ve işletme politikasının belirlenmesinde ihtimal kısıtlı doğrusal programlama yönteminin kullanılması ve muhtelif barajlara uygulaması

TEZ2190Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1996.Kaynakça (s. 77-78) var.vii, 80 s. ; 30 cm.…Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi Tarafından Desteklenmiştir. Proje No: FBE. 95E. 159

Investigation of seasonal thermal flow in a real dam reservoir using 3-D numerical modeling

Investigations indicate that correct estimation of seasonal thermal stratification in a dam reservoir is very important for the dam reservoir water quality modeling and water management problems. The main aim of this study is to develop a hydrodynamics model of an actual dam reservoir in three dimensions for simulating a real dam reservoir flows for different seasons. The model is developed using nonlinear and unsteady continuity, momentum, energy and k-ε turbulence model equations. In order to include the Coriolis force effect on the flow in a dam reservoir, Coriolis force parameter is also added the model equations. Those equations are constructed using actual dimensions, shape, boundary and initial conditions of the dam and reservoir. Temperature profiles and flow visualizations are used to evaluate flow conditions in the reservoir. Reservoir flow’s process and parameters are determined all over the reservoir. The mathematical model developed is capable of simulating the flow and thermal characteristics of the reservoir system for seasonal heat exchanges. Model simulations results obtained are compared with field measurements obtained from gauging stations for flows in different seasons. The results show a good agreement with the field measurements

Change-constrained linear programming method for determination of operation policy and storage capacity of reservoirs

Barajların depolama hacimleri; yapının ekonomisi, işletme politikaları ve kazanılacak net faydayla doğrudan ilişkili olması nedeni ile büyük önem arz etmektedir. Bu çalışmada rezervuar işletmesi ve tasarımında, Doğrusal Karar Kuralı yardımı ile şans Kısıtlı Doğrusal programlama yönteminin litaretürlerdeki iki geliştirilmiş öneriminden yararlanılmış ve Doğrusal Karar Kuralı' nın yeni önerimini kullanan genel amaçlı TURBO PASCAL dilinde bir bilgisayar programı geliştirilmiştir. Bu program Aşağı Seyhan Havzasındaki mevcut ve Planlanan altı baraja uygulanmış, sonuçlar litaretürde önerilen diğer çözüm yöntemlerinin sonuçları ile karşılaştırılmıştır.The storage capacity of a reservoir is a very important peculiarity of it as it directly affects 1. the overall economy of the structure, 2. the operation policies, and 3. the net benefits to be obtained. In this study, a computer program was developed in TURBO PASCAL programming language using chance constrained Linear programming with the Linear Decision Rule. The program was applied to six reservoirs in the lower Seyhan Basin with the historical and the generated flows and the storage capacities and the operation policies, were determined. The results obtained were compared to some other recognized methods