A major part of the globe is made up of seas, rivers, underground waters and oceans, and from those places where a major part of the resources needed by humans comes from these methods and requires engineering constructions, coastal protection is important. . being high Development, sustainable, engineering and selection of the best protection method to organize and stabilize the coast, depend on the sea from the sea. Among the protection methods, we can mention coastal wall structures, which reduce the wave height from the beach by creating damping. In the current research, according to the performance of numerical modeling, laboratory results are used to check the efficiency of Open FOAM software and the k-o SST turbulence model in modeling the individual behavior of the body of the coastal Ivar structure. Considering different conditions in modeling, the total number of 10 tests, 5 in the case of coastal wall structure and 5 without structure in 5 different degrees (6, 7.5, 9, 10.5, 12 cm) and the same conditions (structure height 7.5 cm) was chosen to implement the program. The results showed that the forces have increased compared to the state without the structure, in other words, it can be said that the presence of the structure can be compared to the state without the structure in the depreciation of the experimental force. Since the change of forces to the structures is a function of the height, so it decreases with the increase in the amount of influence.
Considering that pontoon breakwaters are among the most common floating breakwaters, which have many advantages over other types of fixed breakwaters, therefore, in the present study, the performance of the rectangular section of this structure under the conditions of Caspian Sea waves has been studied. In this study, ANSYS AQWA software was used, and the analyzes were carried out in the form of hydrostatic analysis and time history analysis by applying the 20-year average wave conditions of the region and time history analysis under the conditions of regional limit waves. In order to validate and calibrate the model, McCartney's 1985 laboratory data has been used. The results of the research show that in the conditions of hydrostatic analysis, the highest amount of displacement occurred in the Heave movement and the lowest amount of displacement occurred in the Surge movement, which is very insignificant. The displacement in Heave movement under the wave period of 6 seconds has the highest value (1.6142 m) and the lowest value in the period of 2 seconds. Also, in the same condition, the analysis of the amount of rotation around the Z and Y axes is very small compared to the rotation around the X axis. Even the maximum values of the rotation around the Y and Z axes are less than the minimum rotation around the X axis with a value of 6.7504e-05 (°/m) which occurs in a period of 2 seconds.
In Iran, pressurized irrigation systems cover a large area of agricultural land, but water use efficiency remains low because farmers tend to do deficit (over) - irrigation due to their lack of knowledge of crop water requirements. To address this issue, irrigation systems can be automated, and it is important to estimate crop water requirements accurately. This can be done based on soil moisture deficit or meteorological data. The water required can then be applied using a volume meter or by determining irrigation time based on the sprinkler flow rate. The study aimed to compare crop water requirement estimates based on soil moisture deficit and meteorological data, as well as the amount of water applied using volume and time-based methods.The study was conducted in the research farm of Razi University, Kermanshah, Iran, on a sprinkler irrigation system equipped with pressure and flow measuring devices, pressure switches, and electrical valves. The field was under corn cultivation, and four types of irrigation management were evaluated, which included a combination of two methods of determining crop water requirement (soil moisture deficiency and meteorological data) and two methods of irrigation application (time or volume). The four treatments were soil moisture - time (MT), soil moisture - volume (MV), weather - time (WT), and weather - volume (WV). The crop water requirement was calculated using the Penman-Monteith formula based on daily weather data. Soil moisture was measured at different depths one day before irrigation, and the soil moisture deficit was calculated to determine the crop water requirement based on soil moisture. The irrigation volume for each sprinkler in the irrigation cycle was calculated using equations that written in the paper.In the volumetric-based method (treatments WV and MV), the volume of water applied was measured using a water meter with a precision of 0.1 liters, and irrigation was stopped after passing the required volume of water. In the time-based method (treatments WT and MT), the irrigation time was calculated by dividing the irrigation volume by the average flow rate of the sprinklers (3 liters per second), and irrigation was stopped after the calculated duration. The actual sprinkler flow rate was calculated based on the volume of applied water and irrigation time in each treatment and irrigation round. Crop yield was measured at the time of harvest in the studied treatments and a control treatment managed by the Faculty of Agriculture. The irrigation treatments were not applied in the first month of the growth period due to field limitations.The results show that the crop water requirement calculated based on meteorological data at the beginning and end of the growing period was more than the method based on soil moisture. In total, the amount of crop water requirement calculated based on soil moisture was 8% more than the meteorological-based method. The volume of applied water in treatments of MT and WT was 14 and 8% more than in MV and WV treatments, respectively.The actual flow rate of sprinklers was different from the design flow rate due to irrigation situations in other parts of the farm. The average discharge of sprinklers (12 irrigation events) in WT, MT, WV, and MV treatments was 2.79, 3.03, 3.27, and 3.12 l/s, respectively. The irrigation time in volume and time-based methods also showed a significant difference. The irrigation time in MT and MV treatments was 10 and 18% longer than in WT and WV treatments, respectively. The study found that due to the non-uniformity of sprinkler discharge, applying irrigation by volume method is better than the time-based method. The results suggest that the MV treatment, which determined the amount of irrigation based on soil moisture deficit and applied it using a volumetric method, is a suitable option for automating sprinkler irrigation systems in the studied region.
In the sediment washing method under submersible flow, the volume of the discharged sediments depends on various parameters, which can be referred to the depth of the water inside the tank, the depth of the water inside the pond, the output flow from the lower discharger, the size and type of accumulated sediments inside the tank. did To check the mentioned parameters in this research, a physical model with a length of 1 meter, a width of 1 meter and a height of 1.10 meters and by performing various tests using 2 water heights inside the tank, 3 water heights inside the pond and with 3 types of sediment granulation (in total 18 experiments) were investigated and studied. The results of this research show that in sediment washing under pressure, when the lower discharger returns for sediment washing, a sediment washing cone is formed in front of it. The dimensions of the formed sediment washing cone depend on the discharge from the lower discharger, the height of the water inside the tank and the diameter of the sediments accumulated inside the tank, so that the measurement results show that in order to keep the height of submerged water constant, the height of water inside the tank increases. It increases the volume and length of the sediment washing cone. Also, for a fixed water height inside the tank, increasing the submerged water height increases the volume and length of the sediment washing cone.
IntroductionThe overflow structure is used to organize and control the water level in open canals and relaxation ponds. Composite sharp edge overflows are designed in different ways and are made up of several openings in such a way that when there is a shortage of water, The flow only passes through the main section of the spillway and more discharge is created on it, and during the flood, with the increase of the discharge, the upper section also starts working, and as a result, it prevents the return of water and the increase of the water level upstream of the spillway. In this situation, the measurement is done with more accuracy (Boss, 1988). Due to the ability to control the water level and the ease of construction and measurement of flow intensity, sharp edge spillways and sliding gates have been widely investigated. On the other hand, most of the overflows in their upstream cause the formation of a region with relatively still water, which creates favorable conditions for sediments and waste materials to settle in the water, which is considered one of the defects of this structure. With the combination of overflow and gate, the difficulties and disadvantages of using each one alone can be reduced so that materials with sedimentation properties are easily emptied from the gate part and mineral and floating materials are emptied from the overflow (Negm et al, 2002).MethodologyThe experiments of this research were carried out in the hydraulic laboratory channel of the Faculty of Agriculture of Birjand University. The channel used in this experiment has a rectangular cross section with a width of 0.3 meters, a length of 10 meters, a height of 0.5 meters and a maximum flow rate of 30 liters per second. The current research was carried out in the form of establishing flow with constant opening of the gate and different flow rates, as well as establishing flow with opening of different gates and constant flow rate in two slopes of 0.004 and 0.002 to determine the flow coefficient. In order to carry out the present experiment, a semi-circular-rectangular overflow structure and a sliding gate is made of galvanized sheet and installed in the test section.By including all effective parameters and dimensional analysis by Buckingham’s method and considering ρ, v and y as repeated variables, the general equation of dimensionless parameters is obtained as follows after simplification. In the present study, dimensionless parameters Hg/D, y/D and were investigated.Results and discussionAccording to the collected data and the hydraulic and geometrical parameters of the structure, the discharge coefficient of the structure was investigated. The flow coefficient of the combined structure was calculated in two states of constant gate and different flow rates, and constant flow rate and different gates. Also, in order to control some of the experiments, the discharge coefficient of the combined structure was investigated in two slopes of 0.004 and 0.002. In all these researches, the discharge coefficient of the combined structure was between 0.6 and 0.8.ConclusionThe test results show that the discharge coefficient depends on whether the gate is submerged or not and the height of the upstream water. Also, the flow coefficient in the conditions of water passing through the gate decreases with the increase of Y/D parameter, and the flow coefficient increases with the increase of Y/D when water passes through the gateand semi-circular-rectangular overflow. By changing the slope of the floor, the discharge coefficient has not changed significantly and with the decrease of Hg/D, the discharge coefficient is almost fixed and tends to a constant number of 0.74.
