Sharif University of TechnologyScientia Iranica1026-309829620221201Enhancement effect of multi-stage inducing duct on the wind velocity profile301730312286310.24200/sci.2022.58219.5639ENM. TahaniDepartment of Aerospace Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran0000-0003-1852-7153M. MasdariDepartment of Aerospace Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, IranA. HabibiDepartment of Aerospace Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, IranM. MirhosseiniSchool of Advanced Technologies, Iran University of Science and Technology, Tehran, IranJournal Article20210504To extracting power from the wind, the high enough velocity of the wind is the key factor. But, winds with high enough velocities are not available in most areas, and therefore, finding a method to enhance the velocity potential of the low-speed winds has been a serious challenge in wind engineering. In this research study, a hollow duct with a specific configuration, we called Multi-Stage Inducing Duct, is presented which is capable to cause a great enhancement in the velocity profile of the low-speed winds, enough to start most of the small horizontal wind turbines. For example, a three-stage inducing duct can increase the wind velocity from 3 m/s to 9.3 m/s on average at the first stage throat of the duct, which equals an increase of 29-times in wind potential power! This configuration of the duct has been introduced, numerically simulated and the effect of its various geometrical parameters investigated. The effects of wind velocity and the number of the stages on the duct performance are investigated, and finally, a study on the relative effectiveness of adding each of the stages is carried out to help us decide where the upper limit for the number of the stages is.https://scientiairanica.sharif.edu/article_22863_d9dff071eca0bbb713cc807ad53c68df.pdfSharif University of TechnologyScientia Iranica1026-309829620221201Damage diagnosis in circular structures using Cartesian wavelet analysis: A comparison between two structural signals303230482277010.24200/sci.2022.58696.5852ENA. Mahdian ParranyDepartment of Mechanical Engineering, Vali-e-Asr University of Rafsanjan, Rafsanjan, IranS. SeifooriDepartment of Mechanical Engineering, Vali-e-Asr University of Rafsanjan, Rafsanjan, IranH. SharifiDepartment of Mechanical Engineering, Vali-e-Asr University of Rafsanjan, Rafsanjan, IranM. J. KhoshgoftarDepartment of Mechanical Engineering, Faculty of Engineering, Arak University, Arak, IranJournal Article20210710Circular structures are used in a wide variety of engineering mechanisms and devices. In this paper, an effective algorithm on the basis of the complex mappings is proposed to identify defects in circular structures using Cartesian damage detection techniques. The efficacy of the proposed algorithm is demonstrated through damage identification in circular plates using the Cartesian wavelet analysis. The vibration and thermal responses of the structure, as two important structural signals, are imported into the proposed algorithm to evaluate the abilities of the signals in identifying the damage location and severity. Finally, two experimental tests are conducted to explore the efficacy of the proposed algorithm in real applications.https://scientiairanica.sharif.edu/article_22770_cc2472ffb74e518b7cc15bc1db67c349.pdfSharif University of TechnologyScientia Iranica1026-309829620221201Optimal design of flow mode semi-active prosthetic knee dampers304930622284810.24200/sci.2022.58926.5971ENR. S. T. SainiDepartment of Mechanical Engineering, National Institute of Technology Karnataka, Surathkal-575025, India0000-0002-2211-9104H. KumarDepartment of Mechanical Engineering, National Institute of Technology Karnataka, Surathkal-575025, IndiaS. ChandramohanDepartment of Mechanical Engineering, Indian Institute of Technology Madras, Chennai-600036, India0000-0002-0030-3269Journal Article20210824Magnetorheological (MR) fluid devices operate in a variety of modes, including flow, shear, squeeze, and pinch. Among these, the flow mode is the most efficient one and produces large field-induced pressure differences. Although shear mode is the least effective, it is the most commonly utilized in many applications, including prosthetic knee, due to its ease of construction. In this study, two flow mode designs which are twin rod and rotary vane MR dampers are optimally designed for prosthetic knee application. A multi-objective optimization problem with damping force or equivalent torque and mass as the objectives is formulated and the optimal designs are fabricated and experimentally characterized. The twin rod MR damper is found to produce a damping force of 1020 N at 1 A with an optimal mass of 0.71 kg. The rotary vane MR damper is determined to produce a maximum torque of 33 Nm at 1 A with an optimal mass of 1.1 kg. Finally, the designs are compared with many MR fluid based prosthetic knee design configurations. Based on the results, twin rod MR damper is identified as the optimal design configuration for prosthetic knee application.https://scientiairanica.sharif.edu/article_22848_057568be61b31c8d0898e5914c12a023.pdfSharif University of TechnologyScientia Iranica1026-309829620221201Numerical study on the effect of magnetic field and discrete heating on free convection in a porous container306330712293210.24200/sci.2022.59029.6025ENS. SivasankaranMathematical Modelling and Applied Computation Research Group, Department of Mathematics, King Abdulaziz University, Jeddah, Saudi ArabiaM. BhuvaneswariDepartment of Mathematics, Kongunadu Polytechnic College, D. Gudalur, Dindigul, Tamilnadu, IndiaA. K. AlzahraniMathematical Modelling and Applied Computation Research Group, Department of Mathematics, King Abdulaziz University, Jeddah, Saudi ArabiaJournal Article20210908A study has been executed numerically on buoyancy induced convection current in a porous container of square shape with the existence of a uniform magnetic flux. The vertical wall situated at the left side is heated with two discrete heaters and the constant temperature is maintained in the right side. There is no thermal transfer in the horizontal walls. This study involves Brinkman Forchheimer-Darcy extended model. The non-dimensional leading equations are evaluated by the finite volume method. The consequences are examined for different values of the porosity, direction of the magnetic flux, Hartmann number, Rayleigh number and Darcy number. The results interpret that the Hartmann number and the average thermal energy transport are disproportionate to each other. Also the averaged heat transfer and the Darcy number are proportionate to each other.https://scientiairanica.sharif.edu/article_22932_6df9e84ef4dc64502c564291f7584430.pdfSharif University of TechnologyScientia Iranica1026-309829620221201Theoretical study of two-dimensional unsteady Maxwell fluid flow over a vertical Riga plate under radiation effects307230832293810.24200/sci.2022.59949.6514ENB. IshtiaqDepartment of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000, Pakistan0000-0003-4356-9574S. NadeemDepartment of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000, PakistanN. AbbasDepartment of Mathematics, Riphah International University, Faisalabad Campus, Faisalabad, 38000 PakistanJournal Article20220211The heat and mass transfer mechanism has gained importance in technical, industrial, and engineering processes due to the application of thermal radiation in nanomaterials with improved thermal properties. The nanomaterials with improved thermal characteristics can be utilized in the formulation of energy to expand the industrial growth of countries. The effects of thermal radiation on the rate-type fluid passing through a Riga plate are examined in this article. The influence of thermophoresis and Brownian motion also have significant importance. The mathematical explanation of the problem is elaborated with the help of partial differential equations. The coupled nonlinear form of ordinary differential equations is achieved via the appropriate methodology of similarity variables. Utilizing suitable MATLAB software, we have achieved numerical solutions for simplified nonlinear equations. The physical parameters have exceptional impacts on the behavior of velocity, temperature, and concentration fields which are explained with the help of graphs. From this study, it is concluded that the Deborah number has an increasing effect on the pattern of fluid velocity. The rising values of the Prandtl number decline the temperature profile while the higher values of the radiation parameter escalate the temperature profile.https://scientiairanica.sharif.edu/article_22938_5ddd52fd58f31bca063704e033307e6d.pdfSharif University of TechnologyScientia Iranica1026-309829620221201Investigation of gas metal arc welding process parameters of aluminium alloy weldment using Taguchi-grey-fuzzy integrated approach308430972286810.24200/sci.2022.60003.6545ENB. N. SreeharanDepartment of Mechanical Engineering, Kumaraguru College of Technology, Coimbatore, Tamil Nadu, IndiaJ. YoganandhDepartment of Mechanical Engineering, Sri Ramakrishna Engineering College, Tamil Nadu, IndiaR. SudhakarDepartment of Mechanical Engineering, Sri Ramakrishna Engineering College, Tamil Nadu, IndiaT. KannanDepartment of Mechanical Engineering, Amrita College of Engineering and Technology, Nagercoil, Tamil Nadu, IndiaJournal Article20220222Globally, aluminium alloys are being used in many industries. Application of aluminium alloys is realized by many manufacturing processes in which joining processes are inevitable. Joining of aluminium alloys is achieved by various welding processes. One of the appropriate welding processes used to join aluminium alloy is Gas Metal Arc Welding (GMAW). This paper investigates the effect of process parameters of the GMAW process while welding AA 6351 aluminium alloy weldment with the help of an integrated Taguchi–Grey–Fuzzy approach. Taguchi L-16 array was designed by using an orthogonal method to conduct the experiments. From the experimental results, Signal-to-Noise Ratios (S/N ratio) were calculated from which Grey Relational Grades (GRG) were computed. These computed Grey Relational Grades were used as input for the fuzzy controller to find the Grey Fuzzy Relational Grades (GFRG), by which optimized process parameters were found and validated. Furthermore, Analysis of Variance (ANOVA) was used to identify the contributions of the GMAW process parameters over the responses. Subsequently, the effects of process parameters on the weldments were also discussed in detail. By identifying the optimized process parameters and contributing process parameters, the quality of weld joints is improved.https://scientiairanica.sharif.edu/article_22868_dc1acd9054b9af794bde0c9671050006.pdfSharif University of TechnologyScientia Iranica1026-309829620221201Analysis of exergy efficiency for a grid connected PV power plant via different solar exergy models in Samsun, Turkey309831062293410.24200/sci.2022.58211.5619ENS. H. Pour Rahmati KhalejanDepartment of Physics, Ondokuz Mayis University, 55139, Samsun, TurkeyV. KeskinCivil Aviation College, Samsun University, 55420, Samsun, TurkeyJournal Article20210503In this study, power conversion efficiency and the analysis of exergy of a grid-connected photovoltaic (PV) power plant was done by comparing solar exergy models for 12 months. Statistical analysis was used to evaluate the PV exergy efficiency related to solar exergy models. First, solar exergy models proposed by Petela, Spanner and Parrott and the mean of solar exergy-to-solar radiation energy ratio were calculated, and the PV exergy efficiency was analyzed. The results indicate that the average solar exergy-to-solar radiation energy ratio for the Samsun region was 0.93 which are related to Petela and Spanner's model. The ratio for Parrott's model was calculated as 0.99. The results confirm that the power conversion efficiency is in the range of 6.15-8.87%. While PV exergy efficiency related to Parrott's model is seen to vary between 4.85% and 7.09% during 12 months, but in Petela's and Spanner's model it changes from 5.19% to 7.60%.https://scientiairanica.sharif.edu/article_22934_eb1e97beaf7eb26d10d2c98b92895226.pdfSharif University of TechnologyScientia Iranica1026-309829620221201Influence of curvature-dependent channel walls on MHD peristaltic flow of viscous fluid with Hall currents and Joule dissipation310731182286910.24200/sci.2022.58621.5818ENSaba SabaDepartment of Mathematics, COMSATS University Islamabad, Islamabad 44000, PakistanF. M. AbbasiDepartment of Mathematics, COMSATS University Islamabad, Islamabad 44000, PakistanS. A. ShehzadDepartment of Mathematics, COMSATS University Islamabad, Sahiwal 57000, PakistanJournal Article20210628The prime motive of this study is to assess the behavior of curvature-dependent channel boundaries on the MHD peristaltic flow of viscous liquid with heat transportation effects via a curved channel. The analysis is reported by considering the Hall currents, Joule and viscous dissipations effects. Further, no-slip momentum and thermal conditions are incorporated. Mathematical model is subjected to the implication of large wavelength and weaker magnetic Reynolds number schemes. Galilean transformation is used to convert the problem from laboratory frame to wave frame. The solution of the system of equations is executed by employing the numerical method ND Solve (Built-in command in Mathematica). The volume and mean flow rates are computed and examined. Graphical illustrations are provided to evaluate the nature of distinct constraints on velocity, temperature, and rate of heat transportation. Results show that the curvature constraint has significant influences on the mechanical and thermal features of the flow. The damping effects of the magnetic field improve the temperature and rate of heat transportation at the boundary. Moreover, a reduction in thermal transportation rate is noticed for the increasing curvature constraint values.https://scientiairanica.sharif.edu/article_22869_24d067a8edccba5ff46c2fd167b506ce.pdf