Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
6
14
2016
06
01
Evaluation CMIP5 Models In Order to Simulate Rainfall by using a Combination of Precipitation data Network Aphrodit and Satellite Precipitation Persiann-cdr In Khuzestan Province
7
19
EN
Kazem
Rangzan
kazemrangzan@scu.ac.ir
Ali
Shahbazi
alish1980@gmail.com
zahra
jaride
zjride@yahoo.com
Mostafa
Kabolizadeh
<span>One of the most important Limitation General Circulation Models , Large scale are being simulation of climatic variables. So should With Various method are downscaled, The ability to have identified a study area. Choose a suitable GCM model for the study area Very important role In the simulation parameter (precipitation) is intended for future. In this research of CMIP5 Models Contains BCC-CSM1.1.M , MPI-ESM-MR and MPI-ESM-LR was used In order to evaluate three models in the baseline period And determine the best model In order to fit into the study area .The first the Historical and Observation data are divided in to two Periodes: the first half (1983-1992) the period baseline and the second half(1994-2003) the period Validation. Index verification Mean absolute error and MAE Skill score Calculate between models and observation data in the evaluation period before and after Downscaling seasonal in Software Matlab For all Pixels Khuzestan Province. Results show that Befor applying the change factor method BCC-CSM1.1.M Model Error was Less than the other two models , and The other two were similar in terms of error rate. After applying change factor, BCC-CSM1.1.M Model the improvement was driven self and MPI-ESM-MR and MPI-ESM-LR models were ranked as second and third suitable models. So most trusted after the downscaling change factor method for the future under the scenario RCP4.5 for Khuzestan Province was assigned to BCC-CSM1.1.M model.</span>
General Circulation Models,Downscaling,Satellite rainfall Persiann-Cdr,Precipitation network Aphrodit,Evaluation of models
http://wsej.iauahvaz.ac.ir/article_531281.html
http://wsej.iauahvaz.ac.ir/article_531281_532638e87b0048412fe96743c472a6f1.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
6
14
2016
06
01
Comparison of different empirical methods for estimating ddaily reference evapotranspiration in the humid cold climate (case study: Borujen, Shahrekord, Koohrang and Lordegan)
21
38
EN
Kobra
KheiriShalamzari
k.kheiry@yahoo.com
Amir
SoltaniMohammadi
The proposed method for calculation of potential evapotranspiration is Penman-Monteith FAO method, but there are other methods that require less meteorological data but estimates close to the FAO Penman-Monteith method in different climatic conditions. Performance evaluation of these methods on the same basis is prerequisite for selecting an alternative approach in accordance with available data. In this study, daily values of potential evapotranspiration in the period of 21 years (1994-2015) estimated using empirical methods ;Copais, Turc, Hargreaves-Samani, Hargreaves, Ritchie, Irmak and three forms of Valiantzas equation for Borujen, Shahrekord, Koohrang and Lordegan, located in humid cold climate region of Chaharmahal and Bakhtiary province and values were compared with Penman-Monteith FAO method. To compare the results, the root mean square error, error absolute value and coefficient of determination was used. The results show that the equations of Irmak and Valiantzas (RS, T,RH,U ) performs better than the other empirical methods in four stations and the Hargreaves method showed very poor estimation of evapotranspiration than FAO Penman-Monteith method with 92.25 percent relative error. Also, comparison of total potential evapotranspiration estimated with empirical methods determined that equation of Irmak and Valiantzas (Rs, T, RH, U) for all the stations were the most efficient way.
Reference evapotranspiration,Empirical methods,Humid cold climate,Valiantzas
http://wsej.iauahvaz.ac.ir/article_531282.html
http://wsej.iauahvaz.ac.ir/article_531282_391f929cb18bdd5d2a4dbc3fe18147af.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
6
14
2016
06
01
Numerical study, investigation effect of distance and angle of spur dike on average velocity distribution and maximum velocity position at mild 90 degree bend
39
54
EN
Yaser
Ahli
Morteza
Bakhtiari
mortezabakhtiari@yahoo.com
Masih
Moore
Use the Spur dike as one of the easiest ways to protect the costal of the river has always been of interest to River engineers.The aim of this study was numerical investigate, the effect of distance and angle of the spur dikes parameters on the pattern of distribution of average velocity and the location of maximum velocity position at a mild 90 degree bend. For this purpose used ANSYS CFX software for numerical simulation of flow pattern and for calibration of mentioned model used result of Experimental data 3D- velocity data at Bakhtiari et al (2013) research. Variables of this study were 2 length of spur dike equivalent 15 and 25 percent of width of canal, 3 distance equivalent 3,5 and 7 times to spur dike length, 2 angle include of vertical and absorbed spur dike at 3cm to bed which investigated at a flume with R/B=4, width 0.7m and water depth 0.12m. The result of model verification shows good correspondence between the results of numerical models and laboratory. The result show that with increasing the distance between spur dike, the velocities increased too and also caused the increasing the velocity about 75 cm/s on the head of spur dikes. Also the result show that by positioning the absorbent spur dikes the maximum of velocity divert to external bend Therefore, the most destructive is the case for the breakwater.
Spur dike,average velocity distribution,maximum velocity,ANSYS CFX software,mild 90 degree bend
http://wsej.iauahvaz.ac.ir/article_531283.html
http://wsej.iauahvaz.ac.ir/article_531283_8aa50a16f4390ffa00274573d7972f03.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
6
14
2016
06
01
The study of flood flow hydraulic for determining flood bed and river influences points (Atrak River case study)
55
75
EN
Vahid
Yazdani
v.yazdany@yahoo.com
Mohammad
Nazarjani
Hosein Ali
Mirzaie
<span>Measures should be taken to make better use of the rivers in the study, construction and exploitation optimized to contain, mitigate risks and minimize the negative consequences and the improvement of the situation in order to meet human needs and protect the environment there. Route investigated in Khorasan Razavi province and city and river Ghochan is Atrak. Physiographic parameters using digital layers carefully 25,000: 1 in ArcGIS and ArcView analysis and were estimated. To estimate the return periods of floods in the area of methods of analysis, reasoning, Deacon, Krieger and Fuller were used. By comparing the flood estimation by different methods, field visits in this area, soil, vegetation, slope, main channel length, physical parameters and geographical limits of the study, ultimately in the sub Atrak (A1 to A6) results of Deacon, Was considered. Different regimes in the river hydraulic model HEC-RAS has been simulated. The results of the flow regime was selected for the river. Then enter the results of the HEC-RAS model in GIS environment due to the topography of the river and the water surface profile.Results indicated that the average depth of the river terraces formed by the left and right on the beach between 5.2 m and the effects of erosion can be seen in more than 50% along the way. Intervals of high erosion potential (H4T4-H3T3-H3T4) more visibility in the population centers, which are thus the threat of riverbank protection programs during the route. With regard to the agricultural land and rivers in designing and building the necessary measures to be considered in this context. The results of the final balance of the river and move the threshold conditions at all levels stable river cross sections showed that 71 percent of the unstable situation in stable situation is the remaining 29%. Results of sensitivity analysis showed that the highest sensitivity to changes in the parameters of the roughness coefficient and flow area is the width of the upper level.</span>
Atrak River,Flood,hydrology,HEC RAS,Sensitive Analyze
http://wsej.iauahvaz.ac.ir/article_531284.html
http://wsej.iauahvaz.ac.ir/article_531284_613dac42d1a89da14aca2191ce7f509d.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
6
14
2016
06
01
Numerical simulation of free flow over Gabion crump weirs
77
93
EN
Mohammad
Tavakol-Sadrabadi
graduated M.Sc. student in civil engineering-water and hydraulics structures
mohammad.tavakol@outlook.com
Manouchehr
Fathi Moghadam
Reza
Mohammad Pur
Environmentally friendly nature and the direct impact of gabion weirs on the quality parameters of rivers as well as simple design and construction of such structures, has putted them under consideration in the recent years. In this research, Hydraulic parameters of gabion crump weirs including water surface profile, discharge coefficient and through flow discharge are investigated numerically in free flow condition using flow-3d software. A total number of 18 models comprising 6 different geometries studied in 3 different porosities of 43%,44% an 46%. Results indicate that increasing the average diameter of particles (d<sub>50</sub>) leads to the increase of through flow discharge in addition to discharge coefficient and friction loss. Also increasing the side slopes of weirs, decreases the discharge coefficient and through flow discharge. In addition, it is shown that the downstream slope has a slightly larger effect on discharge coefficient where upstream slope’s effect on through flow discharge is higher. Finally, using multivariate non-linear regression analysis, experimental equations were developed in order to estimate the discharge coefficient and the through flow discharge.
discharge coefficient,gabion crump weirs,Numerical simulation,through flow discharge
http://wsej.iauahvaz.ac.ir/article_531285.html
http://wsej.iauahvaz.ac.ir/article_531285_75a445749340394aa6104c57220bcfd5.pdf
Islamic Azad University, Ahvaz Branch
Journal of Water Science & Engineering
2251-6905
6
14
2016
06
01
Influence of intake’s angel and location on sediment rate in bend of river using CCHE2D software
95
107
EN
Rezvan
Zangheneh
Amir Abbas
Kamanbedast
ka57_amir@yahoo.com
Alireza
Masjedi
drmasjedi.2007@yahoo.com
Investigating the features and flow behavior and related component is one of the complex phenomena that make using of software inevitable. The rivers carry sediment content along with water which is created by erosion of riverbed sediment and erosion caused by rainfall or surface runoff flowing over the catchment area. If the action of river dewatering occurs, the entry of sediment into the intake would make new challenges due to the sedimentation. In particular, these factors are valuable for Meander Rivers which have unsteady flow patterns. There are three general approaches to study this process. numerical model was used in this study due to the lower costs compared to existing methods and expediting the process of result obtaining, the model can also be applied to other similar cases to obtain feedbacks resulting from changes in different components that affect the phenomenon under study conditions and evaluate different functions. In this study, simulation of the discharge and sedimentation input into these intakes was investigated to evaluate the hydraulic conditions of flow and sedimentation in the intake with different angles of 30, 45, 60, 75 and 90 by different location (25, 40, 55 and 70) using CCHE2D numerical model that has a sinusoidal-like turn is analyzed. Besides, variation of parameters like velocity, Froude number, shear stress, river bed elevation and total sediment deposits of the river are calculated and discussed. The impact of these different angles on Hydraulic flow was studied. The results of these tests indicated that intake with 90-degree angle and 70 of arc can improve the flow patterns at the inlet. This can overcome sedimentation problems and water shortages in some seasons.
Angle of Intake,River Bend,Sediment Transport,CCHE2D
http://wsej.iauahvaz.ac.ir/article_531286.html
http://wsej.iauahvaz.ac.ir/article_531286_e4150c1659aa3ca843c53d48545afa53.pdf