Akbar Safarzadeh

University of Mohaghegh Ardabili | UMA · Department of Civil Engineering

In this paper, the application of numerical simulation for Computational Fluid Dynamics (CFD) in river Hydrodynamics is represented. In this regard, a case study was carried out in an intended area along the Karoun River‐Iran, using the CFD model, CCHE‐2D. After giving the geometry domain of the field under the study, the depth‐averaged Reynolds...

In the present study, three-dimensional flow structure around two simple series of groynes with different shapes of head was investigated using a numerical model known as SSIIM. The model solved the fully three-dimensional, RANS equation to simulate flow upstream, downstream of the groynes as well as their embayment in which a fully complex 3D flow...

In this work the performance of Reynolds Averaged Navier-Stokes (RANS) simulations to predict the flow structure developed by the presence of a sidewall obstacle in a uniform open-channel shallow flow is discussed. The tested geometry was selected due to its important role in several fluvial applications, such as the control of riverbank erosion an...

Laboratory measurements were conducted to investigate the three-dimensional turbulent flow field around a single straight (SD) and two different T-shape groynes (TH and TF) under smooth flat-bed conditions. An acoustic Doppler velocimeter (ADV) was used in the measurements. Experimental results showed profound effects of the groyne shape on both th...

This paper compares the hydraulics and 3D flow features of the ordinary rectangular and trapezoidal plan view piano key weirs (PKWs) using two phase RANS numerical simulations. The main aim is to investigate effects of the inlet key area and angle of the side walls on discharge capacity of the PKW, while keeping the developing length of the crest i...

Conventional sharp-crested side weirs have limitations in terms of the accuracy of flow rate measurements. For this reason, sharp-crested weirs with a composite cross-section have recently been used. Weirs should mainly have two characteristics: 1- Accurate measurement of flow rate for proper dewatering of the channel 2- Its ability to discharge a...

In this research, the comprehensive hydraulic design of the sharp-crested linear weir is investigated. The experiments were performed in a laboratory flume with a total length of 10 m, a width of 0.5 m, and a height of 0.8 m. The physical model of the weir was made of PVC sheets with constant height and width. To understand the behavior and hydraul...

In this study, the convergence of the flow structure downstream of a trapezoidal labyrinth weir at an angle of 15 degrees to the wall has been investigated. The experiments were performed in a laboratory flume with a total length of 10 m, a width of 0.5 m, and a height of 0.8 m. The physical model of the weir was made of PVC sheets with fixed heigh...

In this study, the hydrodynamics of the three-dimensional structure of the flow in the trapezoidal labyrinth weir at an angle of 15 degrees to the wall has been investigated. The experiments were performed in an experimental flume with a total length of 10 m, a width of 0.5 m, and a height of 0.8 m. The physical model of the weir was made of PVC sh...

Dam break is a very important problem due to its effects on the economy, security, human casualties, and environmental consequences. In this study, 3D flow due to dam break over the porous substrate is numerically simulated and the effect of porosity, permeability, and thickness of the porous bed and the water depth in the porous substrate are inve...

In the present study, a new nonlinear weir called the T-shaped weir (TSW), which is a combination of the labyrinth weir (LW) and the piano key weir (PKW), was introduced, and its hydraulic performance was compared with the PKW. Based on the presence of the vertical walls at the inlet key, outlet key, or both keys, the TSW weirs were classified as t...

In this paper, the 3D numerical modelling of the sloshing phenomenon in rectangular tanks was conducted under the oblique excitation. The effect of the aspect ratio on the maximum side wall, bed hydrodynamic forces and the maximum water run up over the side wall investigated under the intelligent controls. The non-inertial reference frame method wa...

Calibration of the groundwater simulation model is one of the main challenges in the modeling process. In addition, hydrogeological complexities and the lack of field data in terms of time and Q5 space lead to uncertainty in the model. Therefore, the present linked the groundwater simulation model (MODFLOW) and sequential uncertainty fitting approa...

In this paper, the 3D numerical modelling of the sloshing phenomenon in rectangular tanks was conducted under the oblique excitation. The effect of the aspect ratio on the maximum side wall, bed hydrodynamic forces and the maximum water run up over the side wall investigated under the intelligent controls. The non-inertial reference frame method wa...

Mathematical simulation of groundwater resource systems is one of the essential tools in managing these valuable resources and calibration of the groundwater simulation models is the time-consuming, and complicated step of these systems. Automated calibration, developed in recent years by researchers with different algorithms, is one of the effecti...

The present study reports the results of high‐resolution free surface Unsteady Reynolds Averaged Navier‐Stokes (URANS) simulations of the Three Dimensional (3D) flow field in a rectangular pump intake system. The numerical simulations are composed of various scenarios without/with various anti‐vortex devices (AVDs) to suppress the surface and sub‐s...

In this study, hybrid differential evolution algorithms were run to study the three-dimensional mean flow field around straight groynes. The three-dimensional velocity components in a refined mesh around a groyne were measured using an acoustic Doppler velocimeter. Two novel hybrid methods, namely differential evolution-based multilayer perceptron...

In this study, the hydrodynamics of rectangular broad-crested porous weirs were numerically simulated using a nonlinear model between the pressure gradient and flow velocity through the porous medium. Computational fluid dynamics (CFD) analysis has been performed and renormalized group (RNG) k-e model is used as the turbulence closure for Reynolds-...

Laboratory experiments were carried out in order to study the inuence of bed roughness on secondary circulations and lateral flow variability in a straight open channel. Flow -eld and bed shear stress were measured using an acoustic Doppler velocimeter and a particular type of the Preston tube, respectively. All experiments attested to the presence...

In the present paper, three-dimensional flow fields around single straight groynes with various lengths have been discussed. The dataset of the flow field is measured in the laboratory using Acoustic Doppler Velocimeter (ADV). Then, the longitudinal velocity field is modelled using a novel hybrid method of Genetic Algorithm based artificial neural...

The sudden expansion of the mixing layer created in the wake of a single groyne is investigated using Particle Image Velocimetry (PIV). In the region of the sudden expansion a patch of high Reynolds shear stresses are observed. Using low-order representations, created from a Dynamic Mode Decomposition and a search criteria based on a Proper Orthogo...

Preston tube is a shear stress measuring technique which is widely used due to its simple operation and construction. Although application of this technique in smooth bed is convenient and reliable, such application in rough bed is problematic due to the appearance of additional parameters such as roughness length scale and zero-plane displacement....

کارآیی هیدرولیکی سرریزهای ریزشی آزاد برای یک هد ثابت، ارتباط مستقیم با طول سرریز دارد. یکی از معایب سرریزهای متداول، ظرفیت تخلیه پایین آنها بواسطه محدودیت عرض موجود برای اجرای این نوع سرریزها می¬باشد. یکی از راه‌های حل این مشکل، استفاده از سرریز با تاج غیرخطی و افزایش طول عبوری جریان می‌باشد. شكل جديدي از سرريزهاي غيرخطي سرريزهاي كليدپيانويي هستند...

سرریزها بخش اصلی سد برای کنترل و تخلیه سیلاب بوده و ایمنی و پایداری سد در مواقع سیلاب علاوه بر مقاومت بدنه سد، کاملاً وابسته به عملکرد مناسب سرریز در تخلیه آب مازاد از مخزن می‌باشد. بدین منظور از سرریزهای مختلفی با توجه به نوع سد و همچنین ملزومات طرح استفاده می‌شود. سرریزهای کلید‌پیانویی که شکل اصلاح شده سرریزهای کنگره‌ای می‌باشند، جزو سازه‌هایی هس...

يکي از مهمترين مسايل بهينه‌سازي در زمينه مديريت منابع آب، مساله بهره‌برداري بهينه از مخرن سد مي‌باشد. طبق گزارشات ارائه شده يكي از مهمترين دلايل تخريب سدها ناكافي بودن ظرفيت تخليه سرريزها است، به همين دليل طراحي سرريز با ظرفيت عبوري بالا از اهميت ويژه‌اي برخوردار است. سرريزهاي کلیدپیانویی نوع جديدي از سرريزها هستند كه ظرفيت تخليه دبي بسيار بالايي د...

سرریز کلید‌پیانویی یک نوع سازه هیدرولیکی جدید در هر دو بخش پژوهشی و عملی می‌باشد. در حال حاضر درک محدودی درمورد تاثیر پارامترهای مختلف هندسی سرریز کلید‌پیانویی بر عملکرد هیدرولیکی آن وجود دارد. دراين تحقيق جريان عبوري از روي سرريزهای کلید‌پیانویی و کنگره‌ای با استفاده از مدل RNG(k- و بكارگيري نرم افزار ديناميك سیالات محاسباتی FLOW-3Dبصورت سه بعدي...