1387
3
1
31
86
0
پیش بینی زمان واقعی سیل با استفاده از شبکه های عصبی ترکیبی
Real-Time Flood Forecasting Using Hybrid Neural Networks
http://jhyd.iha.ir/article_85445.html
10.30482/jhyd.2008.85445
0
1
Hybrid models which are based on methods which divide a complex simulation problem to severalsimple local models and combine the results, potentially could result in different output. The inputspace in this method is divided into subspaces, and then some single models are assigned to eachspecific region of the space. In this research by using some floods generated by a hydrologic model,advantages of hybrid models in real-time flood forecasting compared to global models wasinvestigated. To do this, the results of a global ANN model which simulates whole of the floodprocesses using a single model, are compared with that of two hybrid models, one consisting of a 4ANN and the other consisting of 8 ANN. The results shows that hybrid models have significantlybetter results in flood forecasting specially in forecasting time and amount of peak discharges. This isvery important in flood forecasting in flood warning systems because of their important role in floodmitigation activities.
1
18
فرشاد
کوهیان افضل
F.
Kooyian Afzal
ایران
f.koohiyan@wri.ac.ir
جمشید
موسوی
J.
Mousavi
ایران
حسین
صدقی
H.
Sedghi
ایران
جهانگیر
پرهمت
J.
Porhemmat
ایران
0
الگوریتم عددی ضمنی بر روی شبکه منحنی الخط برای شبیه سازی جریان های سطح آزاد
Implicit Numerical Algorithm on Curvilinear Coordinates for Simulation of Free-Surface Flows
http://jhyd.iha.ir/article_85446.html
10.30482/jhyd.2008.85446
0
1
Numerical solution of flows with a freely moving boundary is of great importance in practicalapplication such as ship hydrodynamics. Details are given of the development of a two-dimensionalvertical numerical model for simulating unsteady and steady free-surface flows on a non-staggeredgrid in curvilinear coordinates, using a non-hydrostatic pressure distribution. In this model, Reynoldsequation and the kinematic free-surface boundary condition are solved simultaneously, so that thewater surface elevation can be integrated into the solution and solved for, together with the velocityand pressure field. In the computational space, the Cartesian velocity components and the pressure aredefined at the center of a control volume, while the volume fluxes are defined at the mid-point on theircorresponding cell faces. Detailed numerical results are presented for the wave generation above anobstacle and small amplitude Stokes waves. The results show that the numerical algorithm described isable to produce accurate predictions and is also easy to apply.
19
31
میترا
جوان
M.
Javan
ایران
javanmi@gmail.com
مسعود
منتظری نمین
M.
M. Namin
ایران
naminmm@yahoo.com
سیدعلی اکبر
صالحی نیشابوری
S.A.A.
Salehi Neyshabouri
ایران
0
تاثیر مشخصات هندسی ناپیوستگی ها بر رفتار هیدرولیکی و نشت آب از تکیه گاه های سنگی سدهای بتنی قوسی
Evaluation of Geometrical Characteristics of Rock Joints on Hydraulic Behavior and Seepage through the Abutments of Concrete Arch Dams
http://jhyd.iha.ir/article_85447.html
10.30482/jhyd.2008.85447
0
1
Limitation of water flow and seepage from upstream to downstream through the abutments is a majorfactor in design of concrete arch dams. In practice, due to the intensive loading imposed on abutments,the concrete arch dams are usually constructed on the rocky abutments with high degrees of strengthand stiffness. However, the hard rocks have always contained some discontinuities because of theirintrinsic brittle manner. Since these discontinuities are the main ways through which most of seepageis occurred and thus tend to instability of foundation, their hydraulic and mechanical effects must befully considered. In this paper the effects of geometrical parameters such as joints orientation andinitial aperture are studied on hydraulic behavior and seepage through abutments. In addition, theeffect of hydraulic initial aperture which is a hydraulic parameter is treated on the safety of abutments.The results show that the geometrical parameters have dominant influence on the seepage throughabutments and can also endanger the stability of foundation.
33
44
سعید
یزدانی
S.
Yazdani
ایران
محمود
یزدانی
M.
Yazdani
دانشگاه تربیت مدرس
ایران
myazdani@modares.ac.ir
محمدتقی
احمدی
M.T.
Ahmadi
ایران
0
شبیه سازی، تحلیل حساسیت و عدم قطعیت تغییرات تراز آب دریاچه ارومیه نسبت به مولفه های بیلان آبی آن
Simulation of Urmia Lake Level Changes and Its Uncertainty and Sensitivity to Water Budget Components
http://jhyd.iha.ir/article_85448.html
10.30482/jhyd.2008.85448
0
1
This research work is an attempt to simulate and analyze monthly water level changes in Urmia Lake.To this end, water budget, multiple regression and artificial neural networks (ANNs) approaches havebeen investigated, using monthly data of effective components of water budget equation such as inputdischarge, average rainfall and average evaporation. Furthermore, uncertainty and sensitivity analysiswere employed to compare the simulation methods capabilities. The results suggested that ANNsmodel using monthly discharge, rainfall and evaporation as inputs gave best results with lesssensitivity, but greater uncertainty.
45
55
مجید
دلاور
M.
Delavar
ایران
m.delavar@modares.ac.ir
سعید
مرید
S.
Morid
دانشگاه تربیت مدرس دانشکده کشاورزی
ایران
morid_sa@modares.ac.ir
مهدی
شفیعی فر
M.
Shafieefar
ایران
shafiee@modares.ac.ir
0
کالیبره کردن خودکار مدل آبهای زیرزمینی با استفاده از بهینه یابی مقید
Automatic Calibration of Groundwater Models Using Constrained Optimization
http://jhyd.iha.ir/article_85449.html
10.30482/jhyd.2008.85449
0
1
Various optimization techniques for automatic calibration of groundwater models have been usedeffectively over past recent years. The present study is another attempt in the same direction throughwhich a new computer model, developed on the basis of optimization technique, is discussed.Throughout the model, the well-known Finite Element Method (FEM) is utilized to discretize andsolve the governing equations of groundwater flow. For the optimization part, Augmented LagrangeMultiplier Method (ALMM) is used to convert the constrained problem to an unconstrained problem,first. Then Davidon-Fletcher-Powell (DFP) optimization technique is utilized to solve the resultedunconstrained problem. The capabilities of the developed model are illustrated by employing anexample. The results show fairly good performance of the model, although some limitations still exist.
57
70
حمیدرضا
غفوری
H.R.
Ghafouri
استاد گروه عمران، دانشکده مهندسی، دانشگاه شهید چمران اهواز
ایران
ghafouri_h@scu.ac.ir
بهرام
بری
B.
Bari
ایران
0
شبیه سازی عددی رسوب زدایی مخزن سد سفیدرود با اجرای عملیات شاس تحت فشار
Numerical Simulation of Pressure Flushing Process in Sefid-Roud Dam
http://jhyd.iha.ir/article_85450.html
10.30482/jhyd.2008.85450
0
1
Use of water and soil conservation activities to control the soil erosion in Ghezel-Ozan and Shahroudwatersheds is almost infeasible and therefore the Sefid-Roud reservoir sedimentation should beaddressed by other ways. In this direction, it seems that the only applicable, successful and feasibleway is to flush the deposited sediments out of reservoir. In the present study, the filed measured dataof reservoir desiltation process are analyzed. Regarding that the numerical simulation of desiltationprocess can lead to a practical way to optimize the flushing operation by adjusting the bottom outletgates maneuver rule, output hydrograph, reservoir water level fluctuations, in this paper a onedimensional model has been applied to the pressure flushing process. At the end, using computedresults, some useful practical approaches to maximizing the next flushing operations are presented.
71
77
علی
خسرونژاد
A.
Khosronejad
ایران
khosronejad@guilan.ac.ir