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Showing 5 results for karami
Saeed Farzin, Hojat Karami, Shahab Nayyer, Elham Zamiri,
Volume 11, Issue 39 (1-2018)
Abstract
Cylindrical weir is one of the hydraulic structures that due to measurement flow rate and flood control are used, and is less expensive than similar structures. In this study, the numerical model validation is performed with an accredited experimental model in three different diameters (11, 9 and 6.35 cm), and in three different angles (45, 90 and 135 degree) toward the wall with Flow3d software. According to the simulation, in the results with k-ε turbulence model there is a good adaptations than the other turbulence models such as the RNG and LES model, and the correlation coefficient (R2=0.965), indicated that the k-ε turbulence model is the best. Due to increasing the length of weir in oblique position and changing the situation of spillway from direct position to oblique position, discharge coefficient will increase, so leads to increasing of discharge. The results show that in models with complementary angles, because of the similarity of these models in the flow pattern, the discharge coefficients will be almost equal to each other. With increasing the diameters of spillway from 6.35 cm to 11 cm discharge coefficient reduced up to 50%. Maximum of the correlation coefficient between discharge and discharge coefficient for cylinder with 11 cm diameter is equal to 0.95 that show high Effectiveness of discharge on discharge coefficient.
Dr. Saeed Farzin, Dr. Hojat Karami, Mr Milad Fazlollahnejad, Mr Shahab Nayyer,
Volume 12, Issue 41 (7-2018)
Abstract
Flip bucket is the main part of one energy dissipation structure called ski jump system. In this research, hydraulic characteristics such as jet length, velocity, pressure and Froude Number in four discharges are studied by Flow-3D in two models including spillway with simple flip bucket and spillway with approach channel. For turbulence modeling, RNG and k-e models are used. Validation show that k-e model is more accurate. The results indicate that the approach channel model has longer jet length and more energy dissipation compared to the other model. In this model, maximum velocity, equaling 2.30 meter per second, occurs at the beginning of the channel for 20 liters per second discharge. Also, maximum increase percentage in velocity happens in the model of approach channel spillway amounting 32 percent for discharge of 15 liters per second. The results of pressure analysis showed that the pressure changes in the two models have no tangible difference. Moreover, maximum pressure is on the toe of the spillway in the first model amounting 2833 Pa for discharge of 25 liters per second. Additionally, maximum Froude Number (4.5) occurs at jet fall in the simple flip bucket model and in approach channel model it occurs in the channel.
Omid Asadi Nalivan, Amir Sadoddin, Gholam Hoseein Karami, Vahedberdi Sheikh,
Volume 12, Issue 43 (12-2018)
Abstract
Groundwater quality, especially siltation and corrosion, are of great importance considering economic and health concerns. Due to the growing population and increasing water demands in the Hableh-Rud river basin and therefore increasing importance of groundwater, this research aims to assess the potential of corrosion and siltation in groundwater resources. In this research, the Langelier Saturation Index, Ryznar Stability Index, Puckorius Scaling Index and Aggressive Index indicators were used for corrosion and siltation assessment and geostatistical analyses tools in ArcGIS were applied for zonation of the indicators across the watershed. Given the average values obtained (0.67 for LSI; 6.51 for RSI; 6.09 for PSI; 12.89 for AI), a large portion of the study area (about 74%) is faced with a siltation condition. Considering the minimum values of RMSE, the two indices of LSI and RSI were interpolated using the Kriging method, while the IDW and RBF were considered for the interpolation of the PSI and AI indices, respectively. Results suggest that, based on the SI indicator, 75.3% of the total area encounters a siltation condition while the figures change for AI as 72.96%, for PSI as 56.42% and for RSI as 32.17%. In general, assessment of the corrosion and siltation indicators indicates a siltation status for the groundwater resources of the basin, which necessitates developing a suitable management plan to prevent its economic and health consequences. One of the appropriate ways to deal with the siltation issue is to identify critical areas and then adjust water pH to under saturation level.
Ph.d Ebrahim Karimi Sangchini, Ph.d Ali Dastranj, Ph.d Seyed Hossein Arami, Ph.d Samad Shadfar, Ph.d Iraj Vayskarami,
Volume 18, Issue 64 (5-2024)
Abstract
Introduction
Numerous forms of natural dangers and related tragedies containing earthquakes, volcanic eruptions, tsunamis, cloud burst, floods, soil erosion etc. happening the world and amongst such troubling natural hazards landslides are the awful types of greatest recurrent occurrences all everywhere the world. Every year, landslides have affected huge damages of life and stuff, concluded the damages of forests, fruitful cultivated land, habitation area, and network communication in addition to tourist adverts. Additionally, alteration of the earth surface is also responsible for devastating landslides. Iran has confronted numerous categories of natural threats and disasters, for example severe soil erosion concluded gully expansion, vulgar floods, and disturbing landslides. So, because of the numerous occurrences of landslides and huge financial damages have develop national disasters of Iran. The landslide event in Iran has caused about 500 billion financial damages. Landslide susceptibility assessment be able to assistance the planners for final management of environmental squalor and natural resources from delicate damages and eventually development of economic action of this watershed area. The planned methods use both the capability thoughts and ground fact at the like time. This could be taken as a brand-new methodology toward landslide zoning difficulties. The goal of the study is to zonate the hazard of landslide occurrence using maximum entropy (ME) algorithm and compare the effectiveness of this method in locating the sensitivity of landslide occurrence in Karganeh Watershed, Lorestan Province.
Materials and Methods
Karganeh Watershed is located between 33° 25′ 12″ to 33° 37′ 12″ latitude and 48° 23′ 59″ to 48° 44′ 24″ longitude, occupying about 294.2 sq km in the Lorestan Province, west of Iran. This watershed is one of the main sub basins of Karkheh River. One of the most important phases of landslide susceptibility assessment is to identify and prepare a distribution map of current landslides in the watershed. This map was prepared via assembly the information associated with landslides or via analyzing the data from remote sensing and GIS techniques. On behalf of this goal, the distribution map layer of landslides in the watershed was prepared and separated into two sets for model training (70%) and model validation (30%) randomly. Also, 16 causes disturbing the happening of landslides in this watershed were selected permitting to the review of sources and the usage of principal component analysis (PCA), Tolerance and VIF tests. Digital layers of effective factors in geographic information system were equipped. In the next step, the landslide risk map was equipped based on the maximum entropy machine (ME) method. So that evaluate the accurateness of the modeling and compare the efficiency of the method, the index of the area under the virtual performance recognition curve (ROC) was used. Established on the fallouts of the maximum likelihood diagram, geological, land use and slope are the best significant factors inducing the event of landslides in Karganeh Watershed.
Results and Discussion
Landslide inventory map indicated that there are 95 scattered landslides in the Karganeh Watershed. Exaggerated total area through landslide is 635 ha (2.23% of the watershed area). Based on the results of the PCA index, the KMO coefficient was calculated as 0.61, which confirms the necessary correlation between the input variables to perform principal component analysis. Among the 19 components as the number of variables investigated in landslide risk assessment, considering the eigenvalue higher than one, the number of the first two main components was investigated. The results showed that these two main components express nearly 67% of the changes. After investigation, slope, slope direction, elevation classes, geology, distance from the river, distance from the road, distance from the fault, river power index (SPI), topographic moisture index (TWI) and slope length index (LS), topographic position index (TPI), topographic roughness index (TRI) and vector roughness measurement index (VRM), land use, distance from the village, and rainfall were selected as the most effective factors of landslide occurrence in the Karganeh Watershed. According to the Kappa index diagram, geological indicators, land use, slope, topographic roughness index (TRI), slope length and slope direction are the most important influencing parameters. The area under the curve (AUC) based on the relative performance detection curve indicates good accuracy (AUC=0.787) in the validation stage. Permitting to the results of the maximum entropy method, about 28% of the Karganeh Watershed is in the high and very high hazard class of landslide happening.
Conclusion
In this study, it was tried to use all effective factors in order to evaluate landslide susceptibility in Karganeh Watershed. Principal component analysis (PCA), tolerance and VIF were used to determine the relationship between the factors influencing the occurrence of landslides and to determine the most effective factors. It is the carrying capacity of the waterway. It actually determines the effect of topography on erosion. The longer the slope is, the higher the sediment carrying capacity is, and the condition of landslides on the side of the waterway increases. An increase in the topographic roughness index (TRI) indicates uplift and nontectonic activity. Changing the rangeland to rain fed farming and road construction is completed severely in Karganeh Watershed throughout recent years and led to awarding great role of human factors on landslide in comparing other factors. Based on the results obtained from this model, 50.4% of the area of the basin is in the very low and low sensitivity class, 21.6% is in the medium sensitivity class, and 28% is in the high and very high sensitivity regional level. An increase in this index leads to more surface roughness and an increase in slope, which makes landslides more prone to occur.The implementation of landslide management programs based on the results of this research on the Karganeh Watershed can explain the difficulties of domain instability.
Ph.d Ebrahim Karimi Sangchini, Ph.d Ebrahim Yousefi Mobarhan, Mr Iraj Vayskarami, Mis Firouzeh Vayskarami,
Volume 18, Issue 66 (8-2024)
Abstract
Introduction
Flood is one of the natural disasters that leaves a lot of damage in nature. Planning to use seasonal floods, while reducing their destructive effects, provides a new source of water to the consumer. Floodwater spreading is one of the methods that provides the basis for the optimal use of floods. Among the limitations that threaten Floodwater spreading projects is the gradual decrease in the amount of water infiltration in the soil, which is mainly due to the blocking of soil pores due to the spread of small and suspended particles that are carried by the flood. Davudarshid Kouhdasht floodwater spreading research station has been built with the aim of controlling floods, feeding underground water tables and adapting different tree species in this Kouhdasht area. The most important problem of this system is the accumulation of sediments on the surface, which over time has reduced the effectiveness of the system. Davudrashid Kouhdasht Floodwater spreading research station is important because before the construction of this project, Kouhdasht city and Ab Bariki village were exposed to floods. The purpose of this research is to investigate the changes in water permeability in the soil at the Davudrashid Kouhdasht floodwater spreading station, and to compare these changes compared to the control area.
Materials and Methods
The Davudrashid flood distribution station in the coordinates 33ْ 33َ 42ء north latitude and 47ْ 41َ 03ء east longitude (area of about 23 hectares) is located in Kouhdasht plain. This project was put into operation in 1998.This station has 6 sedimentation ponds and 18 expansion channels. First, the scope of the project was determined on the topographic map and an area similar to the floodwater spreading area (similar in terms of climate and topography, soil) was selected as a control. In order to compare the permeability of the field soil with the control field, sampling was done from the soil inside the flooded strips (spreading area) and the land adjacent to the field where the flood does not spread (control area). 28 samples were selected from the Floodwater spreading field and 20 samples based on systematic-random method. In the field of flood distribution between 18 expansion channels, a strip transect was randomly used to measure permeability. The amount of infiltration was recorded using Double ring at time intervals of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 60, 80 and 120 minutes. t-Student test was used in SPSS software for statistical analysis of permeability data. Kruskal-Wallis test was used in SPSS software to compare the changes in water permeability in soil in different areas of Floodwater spreading due to flooding.
Results and Discussion
Examining the collected data shows that the final infiltration in the control area (12.4 cm/h) is more than the flood spreading area (9.2 cm/h). According to the standard infiltration table, both flood and control areas are in the medium permeability class and do not differ much from each other. The t-test at different times between the flood and control areas shows that there is a significant difference at the level of 5 percent between the water permeability in the soil of the flood and control areas at 1, 2, and 30 minutes. At other times, there is a significant difference between the amount of water permeability in the soil of the Floodwater spreading areas and the control at the level of 1 percent. The results of statistical analysis using the Kruskal-Wallis test at different times between the upstream, middle and downstream areas of floodwater spreading show that at times 1, 80, 120 and the sum of the times of the second hour, there is a significant difference in the level of water permeability in the soil of different floodwater spreading areas at the level of 5 and one percent. At other times, in terms of this parameter, there is a significant difference at the level of 5 percent among the areas of flood distribution. The final infiltration speed in the upstream, middle and downstream areas was 8.9, 7.3 and 1.8 cm/hour, respectively. According to the standard penetration table, all three broadcast arenas are in the middle penetration class and do not differ much from each other.
Conclusion
From the results of this research, it is concluded that the floodwater spreading operation has affected the pattern of water permeability in the soil (amount and speed) in the field of Davudrashid Kouhdasht floodwater spreading and has led to a decrease in the average permeability speed. Due to the accumulation of water behind Stacks (inside the arenas) before the exit of excess water from the valves, significant amount of suspended material has settled down and in general has caused a decrease in permeability, which is significant at the level of 1%. It can be concluded from the results of investigating the infiltration rate in different areas of flood spreading, the infiltration rate in the downstream of the floodwater spreading area is higher than the upstream and middle of the area. This conclusion shows that the upstream sedimentation has reduced the rate of water infiltration in the soil. In general, the results of this research show that flood spreading affects soil permeability and causes a slight decrease in soil water permeability over time. Also, the amount of this reduction is different in different areas of floodwater spreading and from the upstream to the downstream of the floodwater spreading area (due to less sedimentation), the rate of infiltration increases slightly, but according to the comparisons related to the final infiltration capacity, it was determined that the spreading area The flood and the control area are not much different in terms of infiltration, and from the results of this research, it can be concluded that after about 30 years of the construction of this system, the infiltration is still appropriate and fast, and we should not worry about such an issue in the coming years. The results of this research can be used for better management of floodwater spreading station on Davudrashid Kouhdasht aquifer.
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