Analysis of Flow Front Characteristics of Convergent and inclined Plane Surface Jet in Stagnant Water Resources

This study presented the results of an experimental study on the dense flow discharging from convergent and inclined plane surface jet in stagnant and deep ambient resources. Development of industrial and commercial activities throughout the world leads to pollution of water resources. For example, The salt water obtaining from desalination process whose density exceeds the one of the ambient water is discharged into the sea by the desalination plants through discharging structures. Therefore, it is essential to study related processes to suitable transfer of effluent into the ambient. With respect to the importance of this matter, extensive studies have been conducted in recent years as physical and numerical modeling on examining and understanding of flow behavior discharging through submerged and surface jets. This study discusses the plunge and impact location under the effect of different variables. The study tests were carried out in a 3.2×0.6×0.9 m3 flume. The Jet fluid obtained from salt dissolution in water was prepared in three concentrations of 5, 15, and 45 g/lit. To show fluid’s moving path, the obtained solution was colored by using a substance with no effect on density changing. The flow rate of the jet fluid in values of 0.042, 0.08 and 0.105 lit/sec was adjusted by using an electromagnetic flow meter with the accuracy of 0.01 lit/sec. The injection of the jet fluid was carried out by using rectangular channels in four convergence angle of 12.5, 25, 45 and 90 degrees and the constant width of 0.06m. Width of the outlet section in all the channels were considered 0.035 m. Discharge channels injected the jet fluid tangent to the surface of the ambient water. Thus, the channels were installed and adjusted on a base at slopes of zero, 0.04 and 0.08 and certain convergence angle. The water depth in the flume was adjusted at a constant value of 0.7m in all experiments. The ambient fluid was settled before injection of the jet fluid. During this time interval, the temperature of the jet fluid and the ambient fluid were measured by a thermometer and their densities were measured by a hydrometer. For each experiment, the moving path of the jet fluid in the receiving ambient was recorded by using a Sony digital camcorder (DSC-WX220) with the frequency of 50 FPS. This camera recorded the images of flow’s section that was placed in front of the flume’s wall and perpendicular to the central vertical plane of the jet flow. The data was obtained by using of images routing process. Based on the results, the 8-percent slope has the longest length of plunge and impact locations. The 8-percent slope provides high initial momentum. Therefore, the flow has further advance in this condition. Slopes of 0 and 4 percent are very close to each other. Although the value of initial momentum exceeds zero in the 4-percent slope, the length of plunge and impact locations in the 4-percent slope are lower than zero slope. The initial momentum is divided into X and Z directions in 4 percent slope, but all initial momentum is in X direction in zero slope. While the longitudinal slope of the discharge channel is fixed, the length of plunge and impact locations reduce with the jet fluid concentration increasing. Density difference and buoyancy force increase with the concentration increasing. Flow becomes denser and it loses its contact with the surface more quickly. Besides that, the length of plunge and impact locations increases with the convergence angle decreasing. The initial momentum and the discharge velocity of jet flow increase with the convergence angle of discharge channel decreasing. Increasing the initial momentum leads to further advance of jet flow. As the ambient has a fixed depth, was seen the location of the plunge point in the range of 1.2 and the location of the impact point depending on the ambient depth. Finally, the ratio of the length of plunge to impact locations for data was within the range of 0.1-0.8.