1389
5
2
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119
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آبشستگی رسوبهای چسبنده در پایین دست کف بند بر اثر جت افقی مستغرق
Scour of Cohesive Material Downstream of an Apron due to Submerged Horizontal Jets
http://jhyd.iha.ir/article_85452.html
10.30482/jhyd.2011.85452
0
1
In this paper, the effect of clay content on the local scouring downstream of a rigid apron due to asubmerged horizontal jet has been studied experimentally. Seven different mixtures of cohesivesediments with clay content equal to 0, 10, 15, 20, 25, 30 and 40 % were used. Results showed that theclay content has an important effect in the scouring process. It shows that with clay content equal to40%, the maximum depth of scour may be reduced up to 80% of the non-cohesive materials. Usingdimensional analysis, a new non-dimensional parameter is introduced which includes the effect ofboth the grain densimetric Froude number and clay content. It was also found that there is a criticalvalue for the mentioned dimensionless parameter, where no erosion occurs below that value. Also,dimensionless equations and graphs are presented to determine the characteristic lengths of the scourhole including the maximum scour depth, the maximum longitudinal extension of the hole and thesand wave height.
1
12
حسین
حمیدی فر
H.
Hamidifar
ایران
hhamidi64@yahoo.com
محمد حسین
امید
Mohammad Hosein
Omid
گروه آبیاری و آبادانی دانشگاه تهران، کرج، ایران
ایران
momid@ut.ac.ir
0
بهینه سازی عملکرد دریچه های سرریز سد برای مهار سیل با استفاده از منطق فازی
Flood Control by Optimization of Spillway Gate Operation using Fuzzy Logic
http://jhyd.iha.ir/article_85453.html
10.30482/jhyd.2011.85453
0
1
At present appropriate utilization of water resources is vital. Development and establishment ofcommunities along rivers have made the safety against floods very significant. Therefore, damoperation management becomes vital and maneuvering of gates is the most important issue in thisregard.Spillway gate operation policies to reduce flood losses and preservation of storage and safety of thedam are studied in this paper. In this regard, multi-stage operation methods are studied and analyzed.The fuzzy logic principles are used to optimize gate operation and overcome weak points of multistageoperation method. Karun III dam is considered as a case study and the five stage flood routingpolicy followed by the fuzzy logic based operation of spillway gates of the reservoir during floods hasbeen applied. The fuzzy logic results in smooth routed hydrographs rather than stepped ones.Eventually, verification of the proposed method has been done by a comparison with the resultsobtained by using the genetic algorithm to optimize gate operation assuming known inflowhydrographs. Results indicate that the proposed method is quite satisfactory.
13
29
نینا
اسدی پور
N.
Asadipoor
ایران
حسین
محمدولی سامانی
H.
Mohamad Vali Samani
ایران
hossein.samani@gmail.com
0
پیش بینی نحوه انتشار سیلاب با استفاده از موج پخشیدگی غیرخطی
Flood Propagation Forecasting Based on Non-linear Diffusive Wave Equation
http://jhyd.iha.ir/article_85454.html
10.30482/jhyd.2011.85454
0
1
Existence of a quick and accurate flood routing model is of great importance for river training as wellas flood forecasting and warning systems in order to prevent or mitigate flood casualties and damages.Diffusive wave is one of the channel routing methods in which acceleration terms have been neglectedin momentum equation. Among different types of diffusive wave models, Cappelaere equation,considering its unique features, was applied in present research. This model is an advection-diffusionequation, including non-linear parameters, with main advantage of no need for topographic andhydraulic characteristics of the river. In this paper, Leapfrog-Dufort Frankel finite differencenumerical scheme was used for discretization and numerical solution of the Cappelaere equationwhich increases computational speed of flood routing. Furthermore, a novel method of estimatingcelerity(C) and diffusivity (D) parameters was proposed which is superior to previous methods. In thismethod, C and D parameters can be calibrated just by observed hydrographs in a reach and areapplicable for future flood forecasting in the same reach. By this method, absolute independency ofparameter estimation in diffusive wave routing method from river geometry, manning roughness andbed slope is obtained. To validate the model and the proposed method of parameter estimation, therouted hydrographs were compared with the dynamic Saint-Venant equations in a synthetic prismaticchannel. Furthermore, the model was calibrated in a 80 km reach, Yasavol-Gharegooni, of Ghezel-Ozan river and results were tested against the observed hydrographs. Using the model, duration ofrouting in the channel and river were found to be 15.7 and 59 seconds respectively. Maximum error inpeak discharge in the channel and river does not exceed 0.04% and 0.24% respectively. Concerningtime to peak, the maximum error in the channel and river were 0.87% and 1.57% respectively. Resultsin the channel and the river showed that the proposed model is not only accurate in predicting peakdischarge and time of peak, but also is successful in Conserving mass of flood.
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47
محمد
دانیالی
M.
Danialy
ایران
احمدرضا
غواصیه
A.R.
Ghavasieh
دانشکده صنعت آب و برق عباسپور
ایران
ghavasieh@pwut.ac.ir
جلال
عطاری
J.
Attari
ایران
0
تعیین ابعاد بهینه آبشکن محافظ با هدف کاهش عمق آبشستگی در اطراف آبشکن ها در بازه مستقیم در آستانه حرکت ذرات بستر
Optimal Dimensions of Protective Spur Dike for Mitigation of Scour Depth around Main Spur Dikes within a Straight Reach for Incipient Motion for Bed Sediment Movement
http://jhyd.iha.ir/article_85455.html
10.30482/jhyd.2011.85455
0
1
Maximum scour depth around a series of spur dikes is one of the important problems in their design.In this paper, the mitigation of scour depth around a series of consecutive spur dikes within a straightreach was investigated by using a protective spur dike located upstream of the first main spur dike.Effect of different parameters of protective spur dike is experimentally investigated including 4 ratiosof protective spur dike length to the first main spur dike length (Lp/Lf) equal to 0.2, 0.4, 0.6 and 0.8,three angles of protective spur dike (B) of 45, 90 and 135 degree and 4 ratios of protective spur dikedistance to the first main spur dike length (X/Lf) equal to 1, 1.5, 2 and 2.5. The experiments wereconducted for the velocity of incipient motion for bed sediment movement and bed size diameter of0.91 mm (D50) and standard deviation of 1.38. The effect of protective spur dike on the flow patternaround the spur dikes was investigated in a rigid bed too. The experiments showed that the properdesign of protective spur dike can significantly mitigate maximum scour depth around the main spurdikes. In particular, the protective spur dike with Lp/Lf =0.8, X/Lf=2, B=45° decreased an average of76.6 percent of scour depth around the spur dikes. The maximum decrease of scour depth around thefirst spur dike (74.7 percent) was obtained by applying the protective spur dike with Lp/Lf=0.8,X/Lf=2.5, B=90°.
49
64
حجت
کرمی
H.
Karami
ایران
hydrocourse@yahoo.com
عبداله
اردشیر
A.
Ardeshir
ایران
کوروش
بهزادیان
K.
Behzadian
ایران
behzadian@aut.ac.ir
0
ساخت و آزمون سامانه کنترل PID برای کانال های آبیاری در مقیاس آزمایشگاهی
Construction and Evaluation of PID Control System for Irrigation Canals in Laboratory Scale
http://jhyd.iha.ir/article_85456.html
10.30482/jhyd.2011.85456
0
1
Automation is one of the main options for improving operations and increasing flexibility inirrigation canals. Construction and testing of related technology is one of initial and mainattempts in reaching this goal.. In this research PID classical control system was constructed,and tested at a laboratory flume. The hardware of the system includes the depth and gateopening sensors, motor, slide gate, electronic boards and computer. The software part of thesystem is the PID control system, which is developed and connected with equipments usingLABVIEW software. To study the performance of the constructed control system, differentscenarios of sudden changes of upstream and downstream flow were tested. Maximum AbsoluteError (MAE), Integral of Absolute magnitude of Error (IAE) and System Response Time (SRT)indicators are used for evaluating the performance of the system. The results showed that theperformance of the developed upstream and downstream control system is appropriate,However, downstream PID control system showed better performance when compared to theupstream PID control system. The developed PID automatic control system and experiencesgained from constructed facilities could be implemented in irrigation canals.
65
75
کاظم
شاهوردی
K.
Shahverdi
ایران
محمد جواد
منعم
M.J.
Monem
عضو هیئت علمی گروه سازه های آبی دانشگاه تربیت مدرس
ایران
monem_mj@modares.ac.ir
0
کارایی گوشه محدب در ورودی خم برای مهار امواج مورب فوق بحرانی
The Efficacy of a Convex Corner at a Bend Inlet for the Control of Supercritical Oblique Waves
http://jhyd.iha.ir/article_85457.html
10.30482/jhyd.2011.85457
0
1
A novel method for the control of supercritical waves is introduced by the installation of a convexcorner at a bend inlet. In this method the negative waves emitted from the convex corner aresuperimposed on the positive waves caused by the outer wall of the bend. Thereby, the heights of thepositive waves are decreased. In the first part of the article, the existing analytical relationships for thesupercritical flow in straight transitions and bends are reviewed and the interactions of waves in themare examined. Then, using the Roe-TVD finite volume method, the supercritical flow in transitionsand bends is simulated numerically. The precision and accuracy of the numerical results in comparisonwith analytical, numerical and experimental solutions of the other researchers are satisfactory. Next,for the reduction of wave height at the outer wall of a curved channel, a small convex corner is locatedat the inner wall of the bend inlet. The interaction of positive and negative waves transforms theoriginal single-hump wave at the outer wall to a smaller double-hump wave. The optimum expansionangle of the convex corner ( ) is a function of the offset breadth to the bend width, d/b, radius ofcurvature to the bend width, rc/b, and the inlet Froude number, Fr0. The numerical studies carried outfor dimensionless widths (d/b=4%, 8%, 12%), in the range of 2.5<Fr0< 4.5 for three bends with (rc/b=10, 15, 20) indicated that using an optimum convex corner the wave height may be decreased between10 to 45%.
77
91
محمد رضا
جعفرزاده
M.R.
Jafarzadeh
عضو هیئت علمی دانشکده عمران دانشگاه فردوسی مشهد
ایران
jafarzad@um.ac.ir
علیرضا
شمخالچیان
A.R.
Shamkhalchian
ایران
محبوبه
جمعه زاده
M.
Jomehzadeh
ایران
0
مطالعه روندیابی سیل در مخازن سدهای پاره سنگی متوالی با توسعه مدل دوبعدی هیدرولیکی برای جریانهای عبوری درون گذر و روگذر
Reservoir Routing in Successive Rockfill Detention Dams using Two-Dimensional Mathematical Model for through and Overtop Flow
http://jhyd.iha.ir/article_85458.html
10.30482/jhyd.2011.85458
0
1
Rockfill dams can be considered as effective and economical tools in flood control. As such,employing successive dams is expected to cause an effective mitigation to flood hydrograph. Sinceflow in coarse media of rockfill dam is turbulent, flow analysis must be based on non-Darcy equations.Flow effects interaction of successive rockfill dams, overtopping flow condition, which maybeexperienced by the first dam, in addition to through seepage flow lead to high complexity ofhydraulics of such dams. In this paper, by introducing the inflow hydrograph to the first reservoir,employing a two-dimensional model for through and overtop dam flow and also employing hydrologicreservoir routing method, it is demonstrated that obtaining the final outflow hydrograph is possible.The mathematical model accuracy was evaluated by comparing its results to experimental data. Themodel results show good agreement with this experimental data. Finally, sensitivity analysisdemonstrated that the model results is much more sensitive to the average particle size of rockfillmedia compared to other parameters such as dam's length and upstream and downstream angles.
93
109
جمال
محمد ولی سامانی
J.
M. V. Samani
استاد گروه سازههای آبی، دانشکده کشاورزی، دانشگاه تربیت مدرس
ایران
samani_j@modares.ac.ir
مهرخ
مکنتیان
M.
Moknatian
ایران
مجید
حیدری
M.
Heydari
ایران
mheydari@basu.ac.ir