Numerical Modeling of Local Scour at the Junction of Open Channels in Flow3D Numerical Model

At the junction of channels, the two corresponding flows of the main and submain channels are diverted from their main alignment and the form and the flow properties change at the junction. Changes in water level profile and depth of flow, velocity distribution, stagnation zone, constriction of public channel, energy loss and also formation of hydraulic jump are among the most important hydraulic variables in this location. For accurate recognition of hydraulic properties of flow and local scour at the junction of channels, physical models are made and constructed. Setting up a physical model requires many conditions and high costs which sometimes are not justifiable, hence appropriate numerical models could be proposed for such options. In this research using Flow3D numerical model, the numerical modelling of the flow has been performed in 3D form utilizing the available laboratory information which is calibrated and validated and accuracy of the numerical modelling, and the corresponding relative error are determined. The calibration and validation of the numerical model results demonstrate that the maximum relative error of the numerical model when simulating for maximum values of scour depth at the flow junction is equal to 8.2%. Also using the numerical model it was found that with passage of time in numerical model, from ....

Removal of Manganese from Aqueous Solution by Natural Zeolite in the Presence of Iron, Chrome and Aluminum Ions

The main purpose of this study is removal efficiency of Clinoptilolite (zeolite) in absorption of manganese in the two modes of single and compound element in solution. The zeolite used in this study was provided from Semnan mines with particle size of 350 mm. The results showed that the optimum pH of both single and compound modes was 5. The kinetics data were analyzed by Lagergrn, Ho et al and Avrami models in the both modes (single and compound). It was found that the data can be expressed satisfactorily by Avrami model. The determination coefficient for Avrami model in both single and compound modes were 0.998 and 0.999 respectively. Also the average absorption rate for manganese in two modes were 0.242 mg/g. min and 0.0146 mg/g. min respectively. Langmuir, Frondlich, Sip's and Radlich-Patterson models were also used in this study. The results showed that Sip's model with determination coefficient of 0.998 and 0.993 and error of 0.0248 and 0.0166 for both single and compound modes respectively, was more reliable for expressing the data than others. The Manganese absorption capacity for single and compound modes were 3.67 mg/g and 2.63 mg/g respectively. The surface area of Zeolite was measured using the methylene blue absorption method and was found 12.31m2/g