Wind and water levels influence wave overtopping and consequent coastal flood threat, which is especially important in hyper-tidal bays where even modest variations in wave heights may be devastating if they coincide with high tides. The influence of wind and wave characteristics on wave propagation, as well as the sensitivity of significant wave height, are numerically investigated along the Gaza Strip's beachfront as an example. Wind waves with a high amplitude and short duration are susceptible to opposing winds, and their steepening effect varies throughout the bay shoreline, underlining the impact of shoreline geometry and bathymetry on wave hazard. The findings contribute to our existing knowledge of the complex interplay between wind and waves, as well as the crucial variables that maximize danger and hazard variability along the coastline. The findings of this study can assist port and harbor managers prevent financial losses due to downtime, influence sustainable coastal sea defense design, and better understand how wave danger may change in the future owing to shifting storm tracks. The findings can also be used to improve coastal infrastructure design and disaster response planning. Two scenarios were investigated with a wind direction of 330 and 30. It seems that when the wind direction is 330, it produces a higher Hs of 1.2 m and relatively larger wave return period with a range of 12-22 s and a higher wave energy dissipation of 220 N/Ms. In contrast, when the wind direction is 30, it produces a smaller HS of 1m with a short wave return period of 15-17s and smaller wave energy dissipation of 120 N/Ms. Overall, a wind direction of 30 has fewer occurring chances over the year but it seems to produce a destructive wave that are spread over the whole coast with a rapid return period.
In this paper three material with equal amount have been chosen to make a mixture, these materials are sand (passing sieve no. 1.18, porosity 0.41), activated carbon (passing sieve no. 4.75, porosity 0.51), crushed bricks (passing sieve no. 20, porosity 0.47), the mixture was used as a bio-filtering media , placed to a height of (1.15) m in a cylindrical filter with diameter of (300)mm and a height of (2)m which is designed and constructed from (PVC). The filter is equipped with three piezometers fixed at three point along the height of the cylindrical filter, in addition to three overflows at different height, and an outlet with control valve. On May 2010 the filter was operated with a synthetic wastewater similar to domestic sewage in order to determine the hydraulic and sanitary characteristics of the filter. Then the feeding of waste water was continued for 3 weeks in order to stimulate the growth of bio-film. On June 2010 the filter was operated with gray water to determine the change in filter characteristics after the bio-film growth, and to evaluate filter efficiency to treat this water for the purpose of reuse. The outcome of this work showed that the mixed media bio-filter, to a certain extent, is similar in hydraulic characteristics (pressure drop and hydraulic load) to granular activated carbon bio-filter, head loss at (1000) mm depth is (59%) of initial pressure, the growth of bio-film leads to increase in head loss by (43%), decrease in flow by (25|%), decrease in pressure by (16%). According to removal efficiency of pollutants, the results shows an efficient removal of BOD5 (86%), turbidity (96%), TDS (81%) at a retention time (60 minute).
One of the most important hydraulic structures which are used in irrigation systems are the broad crested weirs, which can be defined as a vertical barrier in a canal or tank side in which the water may flow freely. This weir can be used to measure the discharge and to raise the water level in the upstream. In this study the effect of longitudinal section on streamlined flow over broad crested weir has been investigated. Loss in energy, working efficiency and the coefficient of discharge have been considered. Experimental study carried out using (25) samples with six different hydraulic heads. The analysis of results indicate that the coefficient of discharge (Cd) increases with increasing Froud Number (Fr) and the most effective slope of upstream and downstream faces of the weir wear (45°) and (60°) respectively, at which the coefficient of discharge demonstrated was (0.644
Abstract In this study the hydraulic performance of single step broad-crested weir was improved. Through analyzing the parameters that have effect on the shape of the step and its influence on the flow characteristics, and energy dissipation percent (E%) downstream (D/S) of the weir. The differential equation of gradually varied flow for the water surface profile over the weir was solved analytically .Furthermore, empirical relations for E% and discharge coefficient (Cd) due to the affecting factors were derived .The results showed that the weir model when the ratio of the length of D/S step to the length of the weir L2/L1=0.5 gives a higher E% in comparison with other weir models. Three types of flow regimes were observed, nappe flow below 350 cm3 /s/cm, transition flow 350-700 cm3/s/cm and skimming flow upper than 700 cm3/s/cm . The comparison between calculated values by the differential equation of gradually varied flow and experimental values gives a good agreement, the maximum difference is about 7%.Two empirical relations were obtained, the first to estimate Cd in terms of the ratio for upstream U/S water head to U/S weir height H/P1 and L2/L1. While the second relation to estimate E% in terms of the ratio for D/S water head to U/S weir height h/P1, L2/L1 and the Froude number Fr2 with a high correlation coefficient . Key words: Hydraulics; weirs ; performance ; dissipation energy.
In recent years, Iraq suffers from exacerbation of the deficit of electrical energy as well as the great environmental pollution resulting from the use of traditional fuels. This called for serious thought to search for using clean and renewable energy sources may available in Iraq.In the present study; small hydropower (i.e. Archimedes screw turbine) are specifically used with a low head at Ramadi Barrage in Iraq. This type of small hydropower station is suitable to apply because not need high storage water or high head in Barrage. The power production in this technology depends on the parameters of the location in which it is placed such as (length L, angle of inclination α, Diameter D,….). The physical model of the Archimedes screw turbine is applied to determine the optimal α. The solid work package with a combination of Computational Fluid Dynamics (CFD) analysis by ANSYS have been used to simulate numerically a three dimensions model to determine the value of power that could be produced by the Archimedes turbine in the Ramadi Barrage. The turbine's performance are tested on two cases which represent low and high discharge investigations with different α (18⁰, 23⁰, 30⁰, 35⁰) based on different flow conditions and different water head between upstream and downstream of the barrage. The results showed that the maximum power production from the barrage is 280,000 watts with α=35° and efficiency η=89.9% for case 1; while; this power becomes 400,000 watts with α=30° but of efficiency η=84.9% for case 2. It is concluded from this research that power production from Ramadi Barrage could be investment to eliminate the deficit in the electrical energy in Iraq.
The current study includes application of QUAL2K model to predict the dissolved oxygen (DO) and Biochemical Oxygen Demand (BOD5) of lower reach of the Diyala River in a stretch of 16.90km using hydraulic and water quality data collected from Ministry of Water Resources for the period (January-April 2014). Google Earth and Arc-GIS technique were used in this study as supported tools to provide some QUAL2K input hydro-geometric data. The model parameters were calibrated for the dry flow period by trial and error until the simulated results agreed well with the observed data. The model performance was measured using different statistical criteria such as mean absolute error (MAE), root mean square error (RMSE) and relative error (RE). The results showed that the simulated values were in good agreement with the observed values. Model output for calibration showed that DO and CBOD concentration were not within the allowable limits for preserving the ecological health of the river with range values (2.51 - 4.80 mg/L) and (18.75 – 25.10 mg/L) respectively. Moreover, QUAL2K was used to simulate different scenarios (pollution loads modification, flow augmentation and local oxygenation) in order to manage the water quality during critical period (low flow), and to preserve the minimum requirement of DO concentration in the river. The scenarios results showed the pollution loads modification and local oxygenation are effective in raising DO levels. While flow augmentation does not give significant results in which the level of DO decrease even with reduction in the BOD5 for point sources. The combination of wastewater modification and local oxygenation (BOD5 of the discharged effluent from point sources should not exceed 15 mg/L and weir construction at critical positions 6.67km from the beginning of the study region with 1m height) is necessary to ensure minimum DO concentrations.
The concern over increasing needs for drinking water and awareness for development of systems to improve water quality both for drinking purposes and for effluents from wastewater treatment and industrial facilities have provided incentives to develop new technologies and improve performance of the existing one. Adsorption technology has many advantages over other treatment methods such as simple design, low investment cost, limited waste production, etc. Synthetic water with a dosing of artificial copper solution (Cu No3) was passed through a PVC column (15 cm diameter, 100 cm length) containing limestone as a filter media in three different sizes, using three different hydraulic rates, and three initial influent copper concentrations (7.04, 4.39, 1.72) ppm .For this study, three experiments have been conducted; continuous batch and field experiment. The up flow roughing filtration is the suitable technique to recover heavy metals present in aqueous solutions, without the need of adding further substances. The filtration results demonstrated that the smaller size of filter media (3.75) mm gave higher removal efficiency (93.75 – 98.80) % than larger filter media (9.50) mm which gave removal efficiency of (67.61 – 94.0) %. This is due to the large specific surface. The smaller size of limestone achieved the longer detention time (49) min, so the removal of Cu was more than (90) % for the (50) min of experiment. At lower flow rate (0.16) L/min, the removal efficiency was higher than at higher flow rate (0.77) L/min. At high flows, there is a reduced period of surface contact between the particles and copper solution. This study also involved three different batch experiments .The removal efficiency was (93- 97) % for the three types of limestone which indicates the importance of limestone media in the removal process. This also indicates that the removal efficiency was increasing with the increase of the limestone volume. Field experiment has been conducted using wastewater from Al- Dura Electric Station on the three types of limestone so that to ensure the laboratory tests. It was achieved good removal efficiency range from (87.5) % to(97.5) % at the high adsorbent dose .To calibrate the physical model, a computer program of multiple regressions is used to assess the relative importance of the predicted variables. The partial correlations indicate that influent concentration of copper, surface loading (flow rate), and detention time are the most important variables while the size of limestone is not important as others.
Local scour is a primary reason for bridge collapse, presenting a complex challenge due to the numerous factors influencing its occurrence. The complexity of local scour increases with clay-sand beds, particularly in predicting scour depth, as empirical equations are inadequate for such calculations. This study aims to predict local scour around cylindrical bridge piers in clay-sand beds using an artificial neural network (ANN) model. The ANN model was developed using 264 observations from various laboratory experiments. Eight variables were included in the ANN model: clay fraction, pier diameter, flow depth, flow velocity, critical sediment velocity, sediment particle size, bed shear strength, and pier Reynolds number. Sensitivity and statistical analyses were conducted to evaluate the impact of each variable and the accuracy of the ANN model in predicting local scour depth in clay-sand beds. The findings indicate that the ANN model predicted local scour with high accuracy, achieving a mean absolute percentage error (MAPE) of 14.6%. All dimensional variables significantly influenced the prediction of local scour depth, particularly clay fraction and bed shear strength, which were identified as the most crucial parameters. Finally, the MAPE values for local scour depth calculated using empirical equations were significantly higher than those for the ANN model, leading to an overestimation of local scour depth by the empirical equations.
Hydrodynamic modeling of viscous flow in porous media was investigated for fourselected filter media crushed silica, crushed anthracite coal, glass beads and crushed garnet.Typical constants that can be used to estimate head loss for some of the most common designof granular media filters were correlated. The effect of several parameters such as porosity(35%-60%) , temperature(20oC-80oC) and media grain size (0.5-2mm) was studied. Empiricalrelationships were developed using a plot of friction vs. Reynolds number similar to those thathad been successfully used for the flow of fluids in pipes. Analytical models were made todevelop an equation for viscous turbulent flow in porous media from first hydraulic principles.Empirical equation was developed to predict pressure drop in porous media as a function ofbed porosity and evaluated the friction factor as a function to flow type.