Investigation of the head loss of ogee spillway and the length of hydraulic jump due to the confliction of the stream lines over the body of ogee spillway
Mohammad
Toozandehjani
Msc. Student, College of Water Science Engineering, Shahid chamran University, Ahwaz.
author
Mahmood
Kashefipour
2Professor, Faculty of Water Science Engineering ,ShahidChamran University
author
text
article
2012
per
Constructing stilling basins usually are expensive, so reduction of stilling dasins length is economically important. The dimensions of the stilling basin depend on the length and sequent depth of hydraulic jump. Therefore, increasing the energy loss in dam structure decreases the length and sequent depth of hydraulic jump and as a result reduces the stilling basin cost. Also in designing of diversion dam, in order to prevent the agricultural land flooding during the flood season, a smaller height of diversion dam is designed and this may produce many difficulties for upstream intake structures.
In this research study a combination of two jets in ogee dam was used, in order to increase the energy loss along the dam structure and to reduce the hydraulic jump length and sequent depth. The laboratory models of ogee dams were designed and built based on the USBR standards with a designed slot near to the toe of the dam. In these experiments the directions of the flow out of the slot were 0, 45 and 90 degrees in respect to the horizontal line. The effect of six discharge ratios (discharge from the slot to the total discharge) for each angle was investigated on the hydraulic jump length and sequent depth. The Froude Number was measured 1.5 to 4.5. The results showed that the angle 45 degrees has the maximum effect on reducing the hydraulic jump length and sequent depth, with an average discharge ratio of 26% the hydraulic jump length being reduced about 50% in comparison with the classic jump. This structure is also able to increase the total discharge coefficient.
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
1
13
https://www.waterjournal.ir/article_70428_d41d8cd98f00b204e9800998ecf8427e.pdf
Effect of some soil physical and chemical properties on permeability in field conditions
Mohammad Ebrahim
Banihabib,
PhD of Civil Engineering, Water Engineering, Assistant professor, University of Tehran, Iran.
author
Mehran
Iranpour
دانشگاه آزاد اسلامی، واحد لنجان، گروه مهندسی عمران، اصفهان، ایران
author
text
article
2012
per
Soils due to different properties have a range of infiltration rates (IR). This study investigates the influence of soil properties on infiltration rate at the field conditions. Infiltration studies were conducted using double ring method (constant head of 5 cm) at 15 sites with 3 replications. The results showed that final IR ranged between 0.8 – 34.6 cm/h and the time required to achieve steady state IR varied from 20-80 min. The texture of soils had significant effect on IR. Increasing clay and silt percentages by 6 and 14.4 times, final IR decreased 5.1 and 38.7 folds, respectively. Reversely, increasing 8 times in sand fraction, final IR increased 14.8 times. Also, among soil chemical properties, lime had the most effect, which increasing 3.6 times in lime, final IR decreased 10.2 times. This result was attributed to lime particles size which is placed in clay and silt fractions. The results indicated the higher important role of physical characteristics, especially particle size distribution than the chemical properties in soil permeability. The findings of his study reveal the important role of lime in arid and semi arid regions.
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
14
25
https://www.waterjournal.ir/article_70431_4ad8ff35472459868be04f4801a1e2f1.pdf
Experimental study of suspended load effect on flow friction factor
on rigid and smooth beds
Mohammad
Amirzadeh Ghasemi
author
Saleh
Koochakzadeh
استاد گروه مهندسی آبیاری و آبادانی دانشگاه تهران
author
Mohammad hossien
omid
دانشیار گروه مهندسی آبیاری و آبادانی دانشگاه تهران
author
text
article
2012
per
The effect of suspended load on friction coefficient has been studied widely by different researchers, yet vast disagreement exists among them which call for further studies in this area. In this study, the effect of suspended load on flow friction coefficient on smooth and rigid beds was experimentally studied. The experimental setup that was used for this study, consists of a 0.2m wide, 20.4m long and 0.3m deep flume, a water reservation tank and sediment mixture tank. A special sediment sampler has been developed for this study and the discharge was measured by using an orifice that was previously calibrated. The compiled data of this study indicated no impact to decrease friction coefficient. Also it is shown that the variation of the friction coefficient depends on particle Reynolds number. The obtained results was compared with that of other researchers results and which revealed that Parker-Coleman's relationship could be considered as the most appropriate one for determining the effect of suspended load on flow friction coefficient.
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
26
39
https://www.waterjournal.ir/article_70432_6300fa600005f79b75ad8a7f7fb0f303.pdf
Evaluation the Potential of LEACHM Model to Predict Soil Moisture, Nitrate Losses and Uptake by Sugarcane
omid
Bahmani
Department of Irrigation, Faculty of Agricultural, University of Bu Ali Sina, Hamedan.
author
text
article
2012
per
This study fulfilled to assess the moisture in soil profile over the study period with LEACHM model and estimation of leaching, denitrification and nitrogen uptake with sugarcane. Irrigation treatments consisted of full irrigation (I1) and others were 85 (I2) and 70 (I3) percent of I1. Experimental fields irrigated with hydroflumes. Nitrogen application were concluded of 150 (N1), 250 (N2) and 350 (N3) kg/ha. Moisture measured from Soil samples collected from field plots in 0.3 m depth increments to 1.2m on a periodic basis. LEACHM model Efficiency (Willmott's index) to simulation soil moisture changed from 0.78 to 0.95 and best regression coefficient occurred in I2 treatment. Simulation of nitrogen losses and uptake indicated that Mean of highest and lowest of leaching was observed in I1 and I3 with 17 and 8 percent. These results showed with leaching and increase of irrigation had a close relationship. High and low rate of denitrification occurred in I1N3 and I1N1 treatment with 19 and 38 percent. Maximum rate of nitrate uptake with 63 and 56 percent in I2N1 and I1N1 and minimum rate with 35 and 37 percent was observed in I1N3 and I3N3 respectively, full irrigation showed the nitrate leached from root zone and couldn’t uptake by plant and deficit irrigation with composing the stress decreased the root uptake.
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
40
51
https://www.waterjournal.ir/article_70434_dede14335fdc50dbc4682c891b9ef12f.pdf
Salt Leaching Process in saline soils through disturbed soil columns
Masoomeh
Delbari
Asistant Professor,Faculty of Agriculture, university of zabol
author
Mahdiyeh
Talebzadeh
دانشجوی کارشناسی ارشد آبیاری و زهکشی، دانشگاه زابل
author
Hormozd
Naghavii
Scientific Member, Research center of Agriculture, Kerman, Tel:09133416298.Email:naghavii@yahoo.com.
author
Ahmad
Gholamalizadeh
Professor,Faculty of Agriculture, university of zabol, Tel:09151043249.Email: a_ahangar2002@yahoo.com.
author
text
article
2012
per
Accumulation of anions and cations in soil solution prevents growth of plant. The main problem in saline soils is related to soluble salts. Saline soils have a large amount of salts; therefore the leaching from these soils is important. This study was conducted to evaluate the movement of solutes using soil columns picked from Azizabad of Bam. Leaching experiments were conducted on columns of five soil textures (clay loam, loam, sandy clay loam, sandy loam, loam sandy). The soils were filled in columns to achieve uniform bulk density of 1.5 g cm-3. The columns were leached with approximately 5 pore volumes (pv). Effluents from each leaching were collected for chemical analysis. Leachate samples were analyzed for soluble cations (Ca2+, Mg2+, Na+ and K+). After completion of the leaching the soil columns were split open and cut into 3 sections, each 10 cm. Soil samples at different column depths were analyzed for EC, Na+,Ca2+ and Mg+. The results showed using water in leaching experiments could reduce solutes concentration and it following saline soils and these soils do not need any amendant. Generally the effect of coarse textured soil on the ion movement is more than in the case of fine textured soil. The solute arrival in effluent solution is ahead when soil texture is coarse. The amount of clay plays an important role for retaining and ions removal from soil. The difference between the amounts of irrigation water needed for salinity removal depends on soil texture. The most common of such reactions is cation exchange
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
54
65
https://www.waterjournal.ir/article_70437_2faed86be57246574062406dda71c143.pdf
Experimental Investigation of Combined flow overWeirs and below Gates
Maryam
Heydari
M.Sc. Student, Dept. of Water Structure Engineering, Faculty of Agricultural, University of Shahid Bahonar Kerman.
author
Mohammad mehdi
Ahmadi
Assistant Professor of Water Structure Engineering, Faculty of Agricultural, University of Shahid Bahonar Kerman.
author
Majid
Rahimpour
استادیار، گروه مهندسی آب، دانشگاه شهید باهنر، کرمان
author
text
article
2012
per
Weirs and gates are frequently used as measuring devices because a simple stage-discharge relationship can be deduced. Weir and gate system is a plate that seated at end of canal and the flow current from over an under it. In this paper, the discharge relationship of Weir and gate system is deduced by a theoretical analysis, based on the application of the Õ-theorem of the dimensional analysis, coupled with an experimental investigation carried out by using a laboratory flume.
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
66
77
https://www.waterjournal.ir/article_70441_4fe6d0b3b1bea402ffc634a819534784.pdf
Experimental study and modeling of critical shear stress for cohesive sediment erosion
Hesam
Fooladfar
PhD student of faculty of Water Science Engineering of Ahvaz Chamran University
author
Manoochehr
Fathimoghadam
Professor of faculty of Water Science Engineering of Ahvaz Chamran University
author
Mahmood
Shafai Bajestan
دانشگاه شهید چمران اهواز، ایران
author
text
article
2012
per
Yet, the estimation of critical shear stress for cohesive sediment erosion as a function of degree of consolidation and elevation of exposed layer of the bed sediment is under consideration around the world. Sediment shear strength in the vicinity of the interface can be a good delegate of critical shear stress. Because one can relate this parameter to some parameters such as volumetric concentration and effective stress which are function of time and space and can be modeled analytically. Moreover one can measure the coefficients such as fractal Dimension, effective stress coefficient, Creep coefficient, lateral stress coefficient, internal friction angle and cohesion coefficient, using experimental techniques. Some of these coefficients are used to be measured by soil mechanical laboratorial experiment. However for measurinf of fractal dimension and effective stress coefficient, there is not any documented method. In this paper, an experimental method has been developed using a settling cylinder for bed sediments of Sefidrud Dam reservoir. Experimental results have shown that every fractal dimension has always been jointed with specific effective stress coefficient. Moreover the best value for fractal dimension is the mode of its frequency distribution. Therefore the best value for effective stress coefficient is its average between the pairs with the same selected fractal Dimension. In General, critical shear stress is very sensitive to fractal dimension and it has been shown that the less fractal dimension, the less rate of critical shear stress with respect to volumetric concentration.
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
78
94
https://www.waterjournal.ir/article_70442_9a0dfaebef68c0a7ba35c6a18d1f2ed7.pdf
Experimental Investigation the Effect of Geometry Parameters of Straight and T Shape Gabion Groynes on Local Scouring
Ali akbar
Abbasi
1 Assistant Prof. Khorasan Razavi Agricultural and Natural Resources Research Center
author
Mohammad
leknejad
سازههای آبی، بخش حفاظت خاک و آبخیزداری، مرکز تحقیقات کشاورزی و منابع طبیعی خراسان رضوی،
author
text
article
2012
per
One of the usual methods for river banks protection is using Gabion groyne structures. A local scouring phenomenon is one of the important problems in hydraulic design of groynes. Due to constriction and downward flow, the scouring can occur around the groynes. In this investigation a laboratory movable bed flume with 18m length, 1.5m width and 0.8m depth was used. To study local scour near the head of unsubmerged Gabion groynes, the groynes were constructed perpendicular to the flume's wall. Two shapes of groyne(straight and T shape), two constriction ratios(20% and 30%) and four ratios of space to length (S/L), were used with one constant bed material and one constant bed slope with three different discharge. Based on the experiment results, for straight S/L=3 and for T shape S/L=4 is recommended the suitable S/L ratios. Regarding the type and shape of groyne, T shape groyne indicated the least scouring and the scouring depth of Gabion groyne was less than of impermeable groyne.
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
95
107
https://www.waterjournal.ir/article_73455_d41d8cd98f00b204e9800998ecf8427e.pdf
Experimental Study of Erodibility in Compacted Cohesive Soils for Embankments
Mojtaba
Abroshan
گروه مهندسی آب، دانشگاه شیراز
author
Mohammadali
Zomorodian
Zomorodian, Shiraz/ Water engineering;
author
text
article
2012
per
فرسایش خاکریزها به علت لبریز شدن آب یکی از علل اصلی خرابی آنها محسوب میشود. مشخصات و درجه تراکم مورد استفاده در ساخت خاکریزها به طور قابل توجهی بر سرعت فرسایش آنها در طی سرریز شدن آب تاثیر میگذارد. هدف این پژوهش بررسی تاثیر درصد رس، انرژی تراکم و میزان رطوبت بر روی فرسایشپذیری خاکهای چسبنده میباشد. خاکهای مورد آزمایش ترکیبی از ماسه با رس بنتونیت در درصدهای مختلف وزنی از 10% تا 20% میباشد. نمونهها در انرژی تراکمهای متفاوت و میزان رطوبتهای مختلف در قالب تراکم استاندارد متراکم گردیده، سپس به وسیله یک فلوم بسته تحت دبیهای متغیر مورد آزمایش فرسایش قرار گرفته و پارامترهای فرسایش برای هر یک به دست آمدند. نتایج نشان میدهد که تراکم نمونه در میزان رطوبت بهینه سبب میشود خاک بیشترین مقاومت در برابر فرسایش را از خود نشان دهد. همچنین نمونههای متراکم شده در قسمت تر منحنی تراکم نسبت به قسمت خشک آن، دارای مقاومت بیشتری در برابر فرسایش میباشند، که تنش برشی بحرانی مربوط به قسمت تر نسبت به قسمت خشک منحنیهای تراکم، حداقل 2/1 و حداکثر 6/1 برابر میباشد. افزایش انرژی تراکم در قسمت خشک سبب افزایش مقدار تنش برشی بحرانی و کاهش سرعت فرسایش میگردد
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
108
116
https://www.waterjournal.ir/article_73457_f81fceaa8c4d0b1d942b802b9583b829.pdf
A Laboratory study of Velocity profile at Hydraulic Jump on Triangular Corrugated Bed
Mahboobeh
Ghazali
دانشجوی دکترای علوم و مهندسی آب دانشگاه شیراز
author
Hossien
Samadi brojni
گروه مهندسی آب، دانشکده کشاورزی، دانشگاه شهرکرد
author
Behzad
Ghorbani
دانشیار گروه مهندسی آب، دانشکده کشاورزی، دانشگاه شهرکرد
author
Aboozar
Rahmati
آبیاری و زهکشی، گروه مهندسی آب دانشگاه شهرکرد
author
text
article
2012
per
In the present research, the hydraulic jump characteristics were studied experimentally over five triangular corrugated beds at the Hydraulics Laboratory of the Department of Water Engineering, University of Shahrekord, Iran. The flume has the dimensions of 0.4 m wide, 0.4 m deep and 12 m long. A total number of 15 tests were carried out for the range of initial Froude number from 6.1 to 13.1. In all tests, effect of triangular corrugated bed on velocity profiles and energy dissipation were studied. The dimensionless hydraulic parameters were determined as a function of the Froude number. The analysis of velocity profiles at different sections of the jump showed that the velocity profiles were similar and different from the profile of the simple plane wall jet. The normalized boundary layer thickness δ/b was equal to 0.39 for jumps on corrugated bed compared to 0.16 for the simple wall jet. It was also found that for similar Froude number the energy loss of jump on corrugated bed is more than the smooth bed (average=11.3%).
Irrigation and Water Engineering
انجمن علمی مهندسی آبیاری و آب ایران
2251-7359
2
v.
4
no.
2012
117
128
https://www.waterjournal.ir/article_73458_ae26a50a382867465c7f15d72db5c776.pdf