Scientia Iranica最新文献_第7页

Investigation on Flow Characteristics of Generic Car Body with Different Boundary Conditions 不同边界条件下通用车身流动特性研究

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-07-08 DOI: 10.24200/sci.2023.59961.6523

S. Keiyinci, O. Baş, Mustafa Atakan Akar

{"title":"Investigation on Flow Characteristics of Generic Car Body with Different Boundary Conditions","authors":"S. Keiyinci, O. Baş, Mustafa Atakan Akar","doi":"10.24200/sci.2023.59961.6523","DOIUrl":"https://doi.org/10.24200/sci.2023.59961.6523","url":null,"abstract":"In automotive aerodynamics, it is not common to focus on a specific vehicle due to restricted access to the CAD geometries, their short life span, and limited validation data. For this reason, researchers prefer generic bodies that look like automobiles such as Ahmed Body in their investigations. However, the absence of moving ground and rotating wheels makes these generic bodies unrealistic for aerodynamic studies. In this context, including wheels in CFD simulations, varying ground, and wheel boundary conditions, and comparing their qualitative and quantitative flow parameters with the original Ahmed Body experiment is the main objective of this paper. Results have shown that changing stationary ground and wheel boundaries into moving and rotating boundaries do have minor effects on wake characteristics and drag coefficients. However, just the presence of wheels on the model increases force coefficients significantly (increment in drag and lift coefficients by 27.32% and 188.5 counts, respectively.) even though these boundaries are stationary. As a result, the absence of moving ground and rotating wheels can be tolerated to some extent (especially for experimental studies in which inclusion of moving and rotating boundaries may have difficulties). However, a study cannot be evaluated exactly with a model without wheels.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"16 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74631247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fabrication of a Solution-Processed IGZO/NiO P-N Diode 溶液处理IGZO/NiO P-N二极管的制备

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-28 DOI: 10.24200/sci.2023.57301.5166

N. Arjmandi, Mohamad Seraj

引用次数: 0

Adaptive Inverse Deep Reinforcement Lyapunov learning control for a floating wind turbine 浮式风力发电机的自适应逆深度强化Lyapunov学习控制

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-28 DOI: 10.24200/sci.2023.61871.7532

Hadi Mohammadian KhalafAnsar, J. Keighobadi

{"title":"Adaptive Inverse Deep Reinforcement Lyapunov learning control for a floating wind turbine","authors":"Hadi Mohammadian KhalafAnsar, J. Keighobadi","doi":"10.24200/sci.2023.61871.7532","DOIUrl":"https://doi.org/10.24200/sci.2023.61871.7532","url":null,"abstract":"Offshore floating wind turbines (FWT) decrease climate change adversial effects without occupying significant land and harvesting fields. Owing to the earth planet unexpected climate, online adaptive feedback control of FWTs will be effective in the sense of optimal and uniform energy capture. In this paper, a deep reinforcement learning (DRL)-based control system is proposed to offset both the disturbance and noise effects. Large variations of wind and water waves generate enormous information give rise to convergent learning of deep neural networks model of the wind turbine. As a result of the disturbance and wind sudden variations, an adaptive inverse control equipped with DRL could easily cope with the inherent drawback of DRL i.e., tracking error. Furthermore, received rewards in the DRL algorithm are passed through the newly designed training algorithm to predict control actions such that the loss function is decreased. The attenuation of disturbance and noise on the tracking performance of closed-loop FWT is clarified through software implementation tests while the weight’s convergency and update rules are proved by the direct Lyapunov theorem.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"69 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77152144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

An Optimal Scenario-Based Scheduling Method for an SOP-included Active Distribution Network Considering Uncertainty of Load and Renewable Generations 考虑负荷和可再生发电不确定性的有源配电网场景调度方法

4区工程技术

Scientia Iranica Pub Date : 2023-06-28 DOI: 10.24200/sci.2023.60823.7005

Pezhman Khalouie, Payam Alemi, Mojtaba Beiraghi

{"title":"An Optimal Scenario-Based Scheduling Method for an SOP-included Active Distribution Network Considering Uncertainty of Load and Renewable Generations","authors":"Pezhman Khalouie, Payam Alemi, Mojtaba Beiraghi","doi":"10.24200/sci.2023.60823.7005","DOIUrl":"https://doi.org/10.24200/sci.2023.60823.7005","url":null,"abstract":"The high penetration of renewable Distributed Generators (DGs) in the Active Distribution Network (ADN) in addition to its advantages brings great challenges for the ADN, due to their intermittent and uncertain generations. Increasing network flexibility using Soft Open Points (SOPs) is an effective solution to overcome these challenges. However, an SOP-based ADN may contain various renewable or Controllable DGs (CDGs), and autonomous interconnected Microgrids (MGs). Accordingly, the uncertainty of load and renewable generation makes its scheduling more complex. In this paper, a novel optimal scenario-based framework is proposed to schedule an SOP-included ADN with multi-interconnected microgrids, based on the forecasted scenarios of demand and renewable DGs generation. In the proposed framework, all technical constraints, such as AC load flow equations, SOP's operational limitations, and DG's production range, are modeled in a Second-Order Cone (SOC) programming format. The energy transaction between the ADN and the other agents, i.e., MGs, and Upstream Network (UN) is also considered. This model can be optimally solved in an acceptable time. To show the effectiveness of the proposed method, it is implemented on the IEEE 33-bus distribution network. The simulation results confirm its high accuracy and speed.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135354069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical simulation of electroosmotic flow in a rectangular microchannel with use of magnetic and electric fields 利用磁场和电场对矩形微通道内电渗透流动进行数值模拟

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-26 DOI: 10.24200/sci.2023.58474.5742

M. Saghafian, Hossein Seyedzadeh, Abolfazl Moradmand

引用次数: 0

CFD Analysis of Liquid-Cooled Heatsink Using Nanofluids in Computer Processors 计算机处理器中使用纳米流体的液冷散热器的CFD分析

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-26 DOI: 10.24200/sci.2023.60327.6739

Gulnaz Topcu, U. Ercetin, Cisil Timuralp

引用次数: 0

Comprehensive Stochastic Analysis Method for Tree-Type PDNs and Ground Pollution on Mixed-Signal PCBs 树型多氯联苯与混合信号多氯联苯地面污染的综合随机分析方法

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-26 DOI: 10.24200/sci.2023.57864.5448

M. Mehri

引用次数: 0

Multi–Port High–Frequency AC–Link and Indirect Matrix Converters: A Generalized Structure 多端口高频交流链路和间接矩阵变换器:一种通用结构

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-26 DOI: 10.24200/sci.2023.59375.6205

H. Hojabri

{"title":"Multi–Port High–Frequency AC–Link and Indirect Matrix Converters: A Generalized Structure","authors":"H. Hojabri","doi":"10.24200/sci.2023.59375.6205","DOIUrl":"https://doi.org/10.24200/sci.2023.59375.6205","url":null,"abstract":"Conventional multi–stage AC/DC/DC, AC/DC/AC, DC/DC/DC, and DC/DC/AC converters are two ports converters used to connect a resource or load to an AC or DC grid. To connect several loads or resources to a grid, these converters can easily be extended to a multi– port converter through a common DC–link, with simplified control and a reduced number of active switches. However, DC–link huge energy storage component increases the converter volume and cost and reduces its lifetime and reliability. On the other hand, most of the resources with these types of converters have fault ride–through problems and the DC–link voltage increases during the grid–side faults. The indirect matrix converter is a two–port high–frequency AC–link (HFAC) converter without any intermediate energy storage component, which can be used to connect just a single source or load to a grid. In this paper, a generalized extension of a two–port indirect matrix converter (and the other HFAC converters) to a multi–port converter is proposed. The modulation method, voltage and current gains, and the reactive power limitation of the proposed structure are also presented. Performances of the proposed structure and its modulation strategy are verified through simulation in MATLAB/SIMULINK environment.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"63 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78826819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

How does the environmental concerns affect the satisfaction of BRT and Metro users? A moderator analysis 环境问题如何影响快速公交和地铁用户的满意度?慢化剂分析

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-26 DOI: 10.24200/sci.2023.59391.6213

Iman Farzin, Mohammadhossein Abbasi, A. Mahpour

引用次数: 0

A Mixed Pseudo-spectral FFT-FE Method for Asymmetric Nonlinear Heat Transfer of a Functionally Graded Hollow Cylinder 功能梯度空心圆柱体非对称非线性传热的混合伪谱FFT-FE方法

IF 1.4 4区工程技术

Scientia Iranica Pub Date : 2023-06-20 DOI: 10.24200/sci.2023.60237.6682

M. Dehghan, A. Moosaie, Mohammad Zamani Nejad

{"title":"A Mixed Pseudo-spectral FFT-FE Method for Asymmetric Nonlinear Heat Transfer of a Functionally Graded Hollow Cylinder","authors":"M. Dehghan, A. Moosaie, Mohammad Zamani Nejad","doi":"10.24200/sci.2023.60237.6682","DOIUrl":"https://doi.org/10.24200/sci.2023.60237.6682","url":null,"abstract":"In this article, a novel spectral method based on the integral transform and finite element (FE) method is introduced for nonlinear thermal analysis of a hollow cylinder under asymmetric boundary excitations. The material properties are temperature-dependent and vary in terms of spatial coordinates. This dependency makes the problem to be nonlinear. The intended nonlinear heat conduction equation is discretized using finite elements in the radial direction. Fast Fourier transform (FFT) technique with the uniform distribution of the harmonics in the circumferential direction, is used to discretize the periodic domain and boundary conditions. The use of the FFT algorithm is accompanied by a significant save in computational times and efforts. In such problems, the Pseudo-spectral technique, as an evolved model of the spectral method, is utilized whenever the material properties vary in terms of the periodic variables or there exists a nonlinear term. The convolution sum technique is appropriately used to transform the nonlinear terms in the Fourier space. Thermal boundary conditions at the inner surface of the cylinder are considered in asymmetrical form. In compliance with the other analytical and numerical solutions, the present mixed-method benefits from the fast rate of convergence and high accuracy.","PeriodicalId":21605,"journal":{"name":"Scientia Iranica","volume":"50 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78265354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0