WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
Browse
3 results
Search Results
Conference Object Renewable Energy Powered Artificial Mixing of the Reservoirs(IAHR-Int Assoc Hydro-Environment Engineering Research, 2023) Hazar, Oguz; Elci, SebnemReservoirs are essential and critical infrastructures and require proper management practices to improve water quality. Thermal stratification observed in the reservoirs impairs the water quality affecting the algae population and the solubility of heavy metals from sediment particles. Artificial mixing methods are widely used to improve water quality in thermally stratified eutrophic lakes and reservoirs. Air diffuser systems, water pumps, and water jets are commonly applied for aeration and mixing purposes. Although these methods proved to be effective in the literature, aeration and pumping equipment consume a great amount of electricity and require complementary infrastructures and facilities resulting in high costs. The presented study focuses on aeration of the water column powered by renewable energy. A Savonius turbine is implemented to an artificial mixing setup tested in the laboratory. The shaft of the turbine is directly connected to the pump so that the motion is transferred to the pump shaft eliminating the need for the production/storage of the electricity. The effectiveness of the wind turbine on destratification of the water column is investigated based on various wind conditions. In the experiments, static and dynamic torque values are monitored using a modified design of a rope brake dynamometer composed of a highly precise torque sensor, pulleys, and, a platform for connecting this torque measurement system to the wind turbine. The system is further evaluated for its destratification efficiency of the water column through the experiments.Conference Object Experimental Investigation of Flow Characteristics of Discretized Triangular Hydrographs(International Association for Hydro-Environment Engineering Research, 2015) Pulat, Aytaç; Ata, Cem; Altınsoy, Sinem; Bombar, Gökçen; Elçi, ŞebnemIn this study effect of discretization of triangular hydrographs on flow characteristics is investigated. All experimental tests are carried out in a rectangular flume of 70 cm width and 18 m length and having a slope of 0.004. The flow rate is measured by an electromagnetic flow meter mounted on the inlet pipe and the time variation of flow depth is monitored at various locations. The point velocities are measured by a side-looking ultrasonic velocity meter at 17 different elevations along the water column by repeating the same hydrograph 17 times in unsteady flows, so that the velocity time series could be obtained at each location. A pump speed control unit (PSCU) is used to generate the hydrograph. The results of a three step discretized hydrograph and a continuous triangular shaped hydrograph generated in the flume are compared. Rising and falling periods of both hydrographs are 5.5 minutes and the base and peak flow rates are 14 l/s and 62 l/s respectively. The time varying mean of velocity time series in both stream-wise and vertical directions are investigated. The velocity profiles as well as the turbulence characteristics are compared with the ones obtained from the triangular hydrograph and the discretized hydrograph at unsteady flow conditions. The effect of discretization of the triangular hydrograph on flow velocities and turbulence characteristics is also discussed.Conference Object An Approach for Estimating Seetling Velocity in Turbulent Flows(International Association for Hydro-Environment Engineering Research, 2015) Elçi, ŞebnemPrecise estimation of the settling velocity of particles in turbulent flows is required for many engineering applications including modeling of the transport of suspended sediments and the transport of particle pollutants. This study attempts to quantify the turbulence from direct measurements at a reservoir and presents an approach for estimation of settling velocities of suspended sediments modified by the quantified turbulence. A novel application of acoustic Doppler instruments for measurement of settling velocities was presented considering the fact that settling velocity of particles are commonly estimated indirectly from the balance of settling and diffusive gradients. In the present study, synchronized 3-D velocity and temperature time series were monitored at Tahtali Reservoir in Turkey where the data were utilized to characterize the turbulence characteristics by various means (i.e. buoyancy flux, Richardson flux and Stokes number) provided in the literature. Stokes' settling velocities modified by the turbulent characteristics were compared with the measured settling velocities to discuss which parameters have the greatest impact on the settling mechanism and need to be considered in the presented approach. The results of the study revealed that, when production of turbulence was high, modified settling velocities matched the monitored velocities better. So; it was concluded that modification of Stokes' settling velocities by turbulent kinetic energy production profiles performs better for high turbulent conditions.