In recent years, many hydraulic, sediment, and environmental researchers focused their studies on river junction hydrodynamics. River junction is an important morphological element of river systems. The incoming Flow from a minor branch causes extensive variation of Flow velocity, Flow discharge, and sediment discharge which results in Flow turbulence in the main channel. The main characteristic of river confluence is the dimensions of Flow Separation Zone. This Zone is developed from the downstream edge where the minor branch enters and extends to some distance downstream into the main channel. There are few parameters affecting the Separation Zone extension including the discharge ratio (Qr) the width ratio (Br) and the downstream Froude number (Frd). The effect of these parameters has been investigated on the Separation Zone length (L) and width (H). Experimental tests have been conducted in a 90 degree junction. The results show that as Qr increase L and H increases and as Frd increases the value of L and H decreases. In this study relations were developed which can be used for prediction of Separation Zone dimensions. The mean value of Separation Zone shape index also has been determined.

Flow Separation in the upstream of the intake channel is a problem which produces an eddy Flow at the intake entrance. It reduces the intake efficiency and the effective width of Flow in intake and increases the sediment deposition in the intake entrance. Therefore, it is essential to identify the dimensions of the Flow Separation Zone. Installation of submerged vanes in intake entrance is a method which has been applied to reduce the size of Flow Separation Zone. In this research, the effects of submerged vanes on the dimensions of Flow Separation Zone were investigated using five models of submerged vanes with different arrangement in four discharges of 15, 20, 25 and 30 Ls-1 in the main channel entrance. The Piney arrangement of submerged vanes was selected as the best model that reduced the size of Flow Separation Zone and established a proper Flow profile in the main channel and intake entrance. Comparing with the pilot model tests, this model reduced the length and width of Flow Separation Zone 36.34%, 32.53%, 34.37%, 30.72% and 27.46%, 31%, 31.33%, 30% at four different discharges of 15, 20, 25 and 30 Ls-1, respectively. Results showed that the ratio of width to length of Separation Zone (shape index of Zone) was between two values 0.2 and 0.28 in the all models.

Study of Separation Zone is so important in right-angled three-branch or four-branch open channel junctions. Some effective parameters in this case are inlet discharge ratio and Flow depth which in this research the effect of inlet discharge ratio and weir height ratios (Flow depth) on Flow pattern and dimensions of Separation Zone has been simulated numerically. Investigation of numerical results showed that k-ω model well validated with experimental results and had good agreement, so that simulation error was less than 20%. Dimensions of Separation Zone in main and side channels were directly proportional with the inlet discharge ratio. Also as increases of height ratio of outlet weirs, Flow depth increases and Separation Zone dimensions decreased. According to the analysis of numerical results, dimensions of Separation Zone in vertical direction, of the channel bed to water surface increased, so that for discharge ratio 0.6 and height ratio of outlet weirs 0.377, length of Separation Zone at the channel bed, 0.1 m up the bed and water surface was about 60 cm, 75 cm and 85 cm, respectively. So of the water surface towards the channel bed, length of Separation Zone decreased about %29.

Background and Objectives: In open channel junctions development of Separation Zone at the downstream channels is one of the engineering challenges. Development of Separation Zone has important role on determination of position of hydraulic structures and also increase of its dimensions caused decreasing of Flow area so that leads to more erosion of the bed. As the Flow is entered to the channel, Flow separated from the wall and a Zone with low pressure and vortex is created that is called Separation Zone. As regards of destructive effects of development of the Separation Zone, researchers always have focused on this case. The aim of this study is to investigate the effects of factors such as inlet discharge ratio, height of outlets weirs and bed elevation of inlet channels on dimensions of the Separation Zone in 90 degrees four-branch junction with subcritical Flow.Materials and Methods: Experiments were carried out in hydraulic Lab of Tabriz University. The setup consists of an intersection of four identical channels which intersect at right angles. Each channel is made from glass with a width 0.4 m and height 0.5 m. Junction was right-angled and bed of the channels was considered horizontal. In this study effects of different geometric and hydraulic parameters such as height of the outlet weirs, bed elevation of the lateral channel and inlet discharge ratio on characteristics of the Separation Zone in outlet channels in 90 degrees four-branch junction with two inlet Flows and two outlet Flows was investigated experimentally. In order to investigate the Flow pattern were used pigment and sawdust and dimensions of the Separation Zone were measured by ruler and meter.Results and Discussion: The results revealed that decreasing height of outlet weirs increases dimensions of the Separation Zone so that minimum variations of (ratio of length of the Separation Zone in main outlet channel to channel width) Lx/bxo was about 45 percents. As the bed elevation of lateral channels increases dimensions of the Separation Zone at the main outlet channel increase which variations of Lx/bxo was between 0.8 to 2.75 but dimensions of the Separation Zone at the lateral outlet channel decrease and variations of (ratio of length of the Separation Zone in lateral outlet channel to channel width) Ly/bxo was at the range of 0.2-2. The results also indicated that as the ratio of outlet weir height of the lateral channel to outlet weir height of the main channel increases, dimensions of the Separation Zone in both lateral and main outlet channels increase so that variations of Ls/bxo for both main and lateral channels were at0.2-1.4 and 0.2-2, respectively. Although the dimensions of the Separation Zone change with respect to different conditions but width to length ratios in lateral and main outlet channels were 0.16 and 0.25, respectively. Finally in order to calculate the dimension of the Separation Zone, regression equations were presented so that experimental and analytical results had good agreement.Conclusion: In this research effect of the inlet discharge ratio, height of the outlet weirs and bed elevation of the lateral channels on dimensions of the Separation Zone in 90 degrees open channel junctions was investigated. Results showed that as increase of the inlet discharge ratio and height of the outlet weirs, dimensions of the Separation Zone increased. Increase of the bed elevation of the lateral channel increased dimensions of the Separation Zone in main outlet channel while decreased dimensions of the Separation Zone in lateral outlet channel. As increased of cy/cx dimensions of the Separation Zone in both outlet channels increased.

Understanding Flow behavior over bedforms is one of the most complex topics in sedimentary engineering. Despite numerous studies that have been conducted on river beds, the understanding of the interaction between Flow and bed in turbid and clear waters is still impoverished. The present study mainly focused on simulating clear and turbid Flows using SSIIM software. This study modeled the Flow through a 12-meter channel with nine consecutive dunes of 1-meter length and 4 cm height. Nine simulations were performed to investigate the effects of Flow velocity and Flow Separation Zone in clear and turbid water. Finally, the results were compared with the experimental results of previous researchers using the PIV. The modeling results showed that the length of the Flow Separation Zone increases with increasing velocity, and the highest probability of Flow Separation occurs at the highest velocity. In turbid Flow, Flow Separation is less than the same Flow condition in clear Flow, and as fluid density increases, the length of the Flow Separation Zone decreases. This study demonstrates the acceptable functionality of the SSIIM software and its accuracy in estimating Flow behavior with and without sediment.

Five-Zone Simulating Moving Bed (SMB) system, designed for ternary Separation, is a modified form of standard four-Zone SMB which is only effective in binary Separation. It was reported in literature that the five-Zone SMB separates the extract-II stream with a lower purity value than that of raffinate and extract-I streams. To address this issue, five Zone SMB was designed, using safety margin method for the Separation of a ternary amino acid mixture comprises of methionine, phenylalanine and tryptophan having linear isotherms values. The operating conditions at fixed Zone-I Flow rate were calculated by using triangle theory and the developed mathematical model was run for the simulation studies with Aspen Chromatography vis 12.1. (2004) simulator. The simulation results of the 2-extract five-Zone SMB system were illustrated for the effect of change in Zone safety factor (b2, b3 and b4) values on the Separation performance (product purity and recovery) and on solutes band propagation behavior at cyclic steady state.

A method for capillary electrophoretic enantiomeric Separation of a racemic clenbuterol has been established with hydroxypropyl-b-cyclodextrin as the chiral selector. General equations and data analysis are presented to relate mobility to the equilibrium constants in simple binding equilibria and used to determine binding constants and thermodynamic parameters for host-guest complexation of clenbuterol enantiomers with hydroxypropyl-b-cyclodextrin as a selector. The effects of b-cyclodextrin type and concentration, buffer type, concentration and pH, as well as Separation voltage and capillary temperature were investigated in detail. A maximal resolution of 6.78 was obtained. The binding constants of the host-guest complex of clenbuterol enantiomers with hydroxypropyl-b-cyclodextrin, KR-CD and KS-CD are 22.50 and 43.09 l mol-1, respectively.

Using lateral intake is a method of floodwater diverting. In arid and semi-arid areas, floodwater contain large amount of sediment that will be carried into the intakes and decreases channel conveyance. Sediment conveys into the intake and settles in the Separation Zone beside the upstream side of lateral channel. Sedimentation in Separation Zone reduces the conveyance of lateral channel, thus it is important to determine the length and width of Separation Zone. Several factors affect on Separation Zone such as the ratio of lateral intake discharge to main channel discharge and angle of lateral channel to the main channel Flow direction. Experiments have been conducted for four degrees of diversion channel. Slope and width of main channel, width Of lateral channel and bed material of main channel are constant in all experiments. In each lateral channel intakes, ten experimental tests have been conducted. The magnitude and direction of velocity in the lateral channel have been measured. By using of bed topography the pattern of sedimentation has been determined. If was found that the Separation Zone in the lateral channel related to the ratio of lateral Flow to main channel Flow and angle of intakes. With increasing the ratio of lateral Flow, the length and width of Separation Zone decrease and with decreasing angle of lateral intake, the length of Separation Zone increase and the width of Separation Zone decrease. For the length and width of Separation Zone some equation have been derived.

The main goal of hydraulic engineers is to design a water intake to deliver the maximum Flow discharge with the minimum sediment entry. Dimensions of the eddy Zone in lateral channel, three dimensional Flow pattern, sedimentation, and sediment entry are the major parameters that must be considered at lateral intakes. In this study, , the effect of Froude number on sediment inclusion into the intake, determination of Separation Zone in lateral channel and the width of Separation line of Flow in front of the intake using three structures of sill, 10 skimming wall and dike in three Flow percentages of 17, 21 and 26 were investigated by experimental investigation. The percentage of Flow diversion is the major cause of the formation of dimensions of Separation Zone such that with increasing the percentage of Flow diversion, width and length of the Separation Zone decreased in the basic and sill experiments. However, by adding a 10 skimming wall, the changing trend is different. At low percentage of Flow diversion, dimensions of the eddy area decreased significantly and it increased with increasing the percentage of Flow diversion. However, in general, the simultaneous usage of a 10 skimming wall and sill structures, dimensions of Separation Zone in lateral intake decreased and the useful width of outlet Flow at lateral intake increased and the Separation Zone and sediment accumulation at the entrance of lateral channel decreased compared to basic and sill experiments. By investigating the width of Separation line of Flow in the surface and near the bed of channel bend, it was found that the Flow diversion rate was the most important factor affecting this hydraulic parameter; since, at surface level of Flow with increasing Flow diversion ratio, this parameter increases and due to the creation of secondary Flow and the change of surface Flow pattern under the influence of the simultaneous application of a 10 skimming wall and dike structures, this parameter increases more. However, near the bed, in basic and sill experiments, this parameter increases with increasing Flow diversion rate. However, the simultaneous application of 10 skimming wall and sill structures, the width of Separation line of Flow near the bed reduces by increasing the diverted Flow and, by adding dike structure to the 10 skimming wall and sill in front of the intake, the width of Flow Separation line decreases more.

Bends along open channels always pose difficulties for water transfer systems. One undesirable effect of bends in such channels, i.e. Separation of water from inner banks, was studied. For the purposes of this study, the literature on the subject was first reviewed, and a strongly-curved open channel was designed and constructed on the laboratory scale. Several tests were performed to evaluate the accuracy of the lab model, data homogeneity, and systematic errors. The model was then calibrated and the influence of curvature on Flow pattern past the curve was investigated. Also, for the first time, the influence of Separation walls on Flow pattern was investigated. Experimental results on three strongly-curved open channels with a curvature radius to channel width ratio of 1.5 and curvature angles of 30o, 60o, and 90o showed that, in all the cases studied, the effect of Flow Separation could be observed immediately after the curve. In addition, the greatest effect of Flow Separation was seen at a distance equal to channel width from the bend end. In the presence of middle walls and Flow Separation, the effect of water Separation reduced at the bend, especially for a curvature of 90o.