Pub Date : 2024-01-23DOI: 10.37934/cfdl.16.6.120130
Rafael Ramirez, Andrés Rodríguez, Jonathan Fabregas, Heriberto Maury
An analysis using computational modeling by finite elements of the phenomenon of elastohydrodynamic lubrication (EHL) was carried out for a transmission system of pinion gear in a crankcase with partial filling lubrication. The analysis utilized tribological studies describing the contact behavior characteristics of solid surfaces with the lubrication film caused by dragging and splashing. Furthermore, the characteristics of the Reynolds-Hertz model for this type of phenomena are described, as well as the equations of elastic deformation and elastic displacements along with the geometry of the non-concordant bodies in contact. This was done by modeling the Lagrangian-Eulerian type for non-Newtonian fluid, implementing multiphysics coupling methods. The pressure profile of the lubricant films, the temperature reached by the lubricant, and the von Mises stress at the contact were obtained, showing a good approximation with the related results, indicating a range of 30 MPa to 900 MPa of pressure in the lubricant film and von Mises stress ranging from 30 MPa to 100 MPa in the contact area of the gear tooth.
利用有限元计算模型对曲轴箱中的小齿轮传动系统的弹性流体动力润滑（EHL）现象进行了分析。分析利用了摩擦学研究，描述了固体表面与由拖曳和飞溅引起的润滑膜的接触行为特征。此外，还描述了此类现象的雷诺-赫兹模型的特征，以及弹性变形和弹性位移方程，以及接触的非和谐体的几何形状。这是通过对非牛顿流体进行拉格朗日-欧勒式建模，并采用多物理场耦合方法实现的。获得了润滑油膜的压力曲线、润滑油达到的温度以及接触处的 von Mises 应力，显示出与相关结果的良好近似性，表明润滑油膜的压力范围为 30 兆帕至 900 兆帕，齿轮齿接触区域的 von Mises 应力范围为 30 兆帕至 100 兆帕。
{"title":"Modeling and Simulation of Elastohydrodynamic Lubrication in Spur Gears","authors":"Rafael Ramirez, Andrés Rodríguez, Jonathan Fabregas, Heriberto Maury","doi":"10.37934/cfdl.16.6.120130","DOIUrl":"https://doi.org/10.37934/cfdl.16.6.120130","url":null,"abstract":"An analysis using computational modeling by finite elements of the phenomenon of elastohydrodynamic lubrication (EHL) was carried out for a transmission system of pinion gear in a crankcase with partial filling lubrication. The analysis utilized tribological studies describing the contact behavior characteristics of solid surfaces with the lubrication film caused by dragging and splashing. Furthermore, the characteristics of the Reynolds-Hertz model for this type of phenomena are described, as well as the equations of elastic deformation and elastic displacements along with the geometry of the non-concordant bodies in contact. This was done by modeling the Lagrangian-Eulerian type for non-Newtonian fluid, implementing multiphysics coupling methods. The pressure profile of the lubricant films, the temperature reached by the lubricant, and the von Mises stress at the contact were obtained, showing a good approximation with the related results, indicating a range of 30 MPa to 900 MPa of pressure in the lubricant film and von Mises stress ranging from 30 MPa to 100 MPa in the contact area of the gear tooth.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"122 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139605644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Investigation of Magneto Hydrodynamics Properties of Reiner–Philippoff Nanofluid with Gyrotactic Microorganism in a Porous Medium Nanofluids have many potential applications in engineering, medicine, and biotechnology due to their enhanced thermal, electrical, and optical properties. However, the flow and heat transfer characteristics of nanofluids are influenced by various factors, such as the type and size of nanoparticles, the base fluid, the magnetic field, the radiation, the chemical reaction, and the presence of microorganisms. Therefore, it is important to study the effects of these factors on the nanofluid flow and heat transfer using mathematical models and numerical methods. One of the mathematical models that can describe the nanofluid flow is the Reiner-Philippoff model, which is a classical non-Newtonian fluid model that accounts for the shear-thinning behaviour of some fluids. The Reiner-Philippoff model has been used to study the nanofluid flow over a stretching sheet, which is a simplified model of many industrial processes involving stretching or shrinking surfaces. However, most of the previous studies have neglected the effects of the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection on the nanofluid flow over a stretching sheet. The objective of this paper is to fill this gap by conducting a numerical investigation of the effects of the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection on a Reiner-Philippoff nanofluid of MHD flow through a stretching sheet. This also considers the effects of thermophoresis and Brownian motion, which are two mechanisms that govern the transport of nanoparticles in nanofluids. The article utilized a similarity transformation to reduce the governing partial differential equations into ordinary differential equations, which are then solved by using the MATLAB computational tool bvp4c technique. The paper also employs a hybrid numerical solution method using Runge-Kutta fourth order with a shooting technique and an optimization technique using the Bayesian regularization method for Runge-Kutta to improve the accuracy of the prediction outcomes. The main finding of this paper is that the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection have significant effects on the velocity, temperature, concentration, and motile microorganism profiles of the nanofluid flow over a stretching sheet. The paper also discusses how these effects can be controlled by varying the relevant parameters. This provides graphical results for the profiles of velocity, temperature, concentration, and motile microorganisms for different values of these parameters. The study also compares its results with some existing results in the literature and finds good agreement.
{"title":"Investigation of Magneto Hydrodynamics Properties of Reiner–Philippoff Nanofluid with Gyrotactic Microorganism in a Porous Medium","authors":"S.K. Prasanna Lakshmi, Sreedhar Sobhanapuram, S.V.V Rama Devi","doi":"10.37934/cfdl.16.6.119","DOIUrl":"https://doi.org/10.37934/cfdl.16.6.119","url":null,"abstract":"Investigation of Magneto Hydrodynamics Properties of Reiner–Philippoff Nanofluid with Gyrotactic Microorganism in a Porous Medium Nanofluids have many potential applications in engineering, medicine, and biotechnology due to their enhanced thermal, electrical, and optical properties. However, the flow and heat transfer characteristics of nanofluids are influenced by various factors, such as the type and size of nanoparticles, the base fluid, the magnetic field, the radiation, the chemical reaction, and the presence of microorganisms. Therefore, it is important to study the effects of these factors on the nanofluid flow and heat transfer using mathematical models and numerical methods. One of the mathematical models that can describe the nanofluid flow is the Reiner-Philippoff model, which is a classical non-Newtonian fluid model that accounts for the shear-thinning behaviour of some fluids. The Reiner-Philippoff model has been used to study the nanofluid flow over a stretching sheet, which is a simplified model of many industrial processes involving stretching or shrinking surfaces. However, most of the previous studies have neglected the effects of the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection on the nanofluid flow over a stretching sheet. The objective of this paper is to fill this gap by conducting a numerical investigation of the effects of the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection on a Reiner-Philippoff nanofluid of MHD flow through a stretching sheet. This also considers the effects of thermophoresis and Brownian motion, which are two mechanisms that govern the transport of nanoparticles in nanofluids. The article utilized a similarity transformation to reduce the governing partial differential equations into ordinary differential equations, which are then solved by using the MATLAB computational tool bvp4c technique. The paper also employs a hybrid numerical solution method using Runge-Kutta fourth order with a shooting technique and an optimization technique using the Bayesian regularization method for Runge-Kutta to improve the accuracy of the prediction outcomes. The main finding of this paper is that the Arrhenius reaction, thermal radiation, viscous dissipation, and bio-convection have significant effects on the velocity, temperature, concentration, and motile microorganism profiles of the nanofluid flow over a stretching sheet. The paper also discusses how these effects can be controlled by varying the relevant parameters. This provides graphical results for the profiles of velocity, temperature, concentration, and motile microorganisms for different values of these parameters. The study also compares its results with some existing results in the literature and finds good agreement.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"42 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139603588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-23DOI: 10.37934/cfdl.16.6.157168
Meftah Hrairi, Faical Baghdadi, Waqar Asraar
In this study, erosion patterns and magnitude are compared between the outputs of 2D and 3D CFD models in contraction and expansion geometries. ANSYS Fluent software was used to model a circular cross-section geometry with a contraction and the results were compared to published experimental data. The simulation findings showed that there is good agreement between the 2D and 3D CFD models and the experimental data in terms of fluid flow properties such as velocity profiles and magnitude. It also demonstrated that the 2D and 3D CFD models' representations of erosion patterns and magnitudes are equivalent. The 3D CFD simulations were able to provide more information than the 2D CFD simulations, particularly in terms of erosion distribution over the entire geometry.
{"title":"A Numerical Comparison of 2D and 3D CFD Modelling for Contraction and Expansion Geometries with an Emphasis on Solid Particles Erosion","authors":"Meftah Hrairi, Faical Baghdadi, Waqar Asraar","doi":"10.37934/cfdl.16.6.157168","DOIUrl":"https://doi.org/10.37934/cfdl.16.6.157168","url":null,"abstract":"In this study, erosion patterns and magnitude are compared between the outputs of 2D and 3D CFD models in contraction and expansion geometries. ANSYS Fluent software was used to model a circular cross-section geometry with a contraction and the results were compared to published experimental data. The simulation findings showed that there is good agreement between the 2D and 3D CFD models and the experimental data in terms of fluid flow properties such as velocity profiles and magnitude. It also demonstrated that the 2D and 3D CFD models' representations of erosion patterns and magnitudes are equivalent. The 3D CFD simulations were able to provide more information than the 2D CFD simulations, particularly in terms of erosion distribution over the entire geometry.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"106 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139606034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research article deals with the impact of Activation energy and Hall current on an electrically conducting nanofluid flow past a continuously stretching surface with Diffusion thermo and thermal diffusion has been explored. Transverse magnetic field with the assumption of small Reynolds number is implemented vertically. Appropriate similarity transformations are utilized to transform the governing partial differential equations into the non-linear ordinary differential equations. Numerical solutions for the dimensionless velocity, temperature and nanoparticle concentration are computed with the help of the shooting method. The impact of each of the Activation energy, Hall current parameter, Brownian motion parameter, thermophoresis parameter and magnetic parameter on velocity, concentration and temperature, is discussed through graphs. The skin friction coefficient along the x−and z−directions, the local Nusselt number and the Sherwood number are calculated numerically to look into the inside behavior of the emerging parameters.
本研究文章探讨了活化能和霍尔电流对流经具有热扩散和热扩散的连续拉伸表面的导电纳米流体的影响。在小雷诺数假设下，横向磁场被垂直施加。利用适当的相似变换，将支配偏微分方程转换为非线性常微分方程。在射流法的帮助下，计算了无量纲速度、温度和纳米粒子浓度的数值解。通过图表讨论了活化能、霍尔电流参数、布朗运动参数、热泳参数和磁性参数对速度、浓度和温度的影响。沿 x 和 z 方向的皮肤摩擦系数、局部努塞尔特数和舍伍德数均通过数值计算得出，以研究新出现参数的内部行为。
{"title":"Impact of Activation Energy, Diffusion Thermo, Thermal Diffusion and Hall Current on MHD Casson Fluid Flow with Inclined Plates","authors":"Subhan Kanchi, Prabhakara Rao Gaddala, Shobalatha Gurram","doi":"10.37934/cfdl.16.6.90108","DOIUrl":"https://doi.org/10.37934/cfdl.16.6.90108","url":null,"abstract":"This research article deals with the impact of Activation energy and Hall current on an electrically conducting nanofluid flow past a continuously stretching surface with Diffusion thermo and thermal diffusion has been explored. Transverse magnetic field with the assumption of small Reynolds number is implemented vertically. Appropriate similarity transformations are utilized to transform the governing partial differential equations into the non-linear ordinary differential equations. Numerical solutions for the dimensionless velocity, temperature and nanoparticle concentration are computed with the help of the shooting method. The impact of each of the Activation energy, Hall current parameter, Brownian motion parameter, thermophoresis parameter and magnetic parameter on velocity, concentration and temperature, is discussed through graphs. The skin friction coefficient along the x−and z−directions, the local Nusselt number and the Sherwood number are calculated numerically to look into the inside behavior of the emerging parameters.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"37 21","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139603567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-23DOI: 10.37934/cfdl.16.6.146156
Nurul Amira Zainal, Iskandar Waini, Najiyah Safwa Khashi’ie, Roslinda Nazar, Ioan Pop
Heat transfer is commonly utilized in diverse industrial applications, including the manufacturing of paper, the cooling of electrical devices, and the synthesis of new substances. Hence, this study aims to investigate the effect of heat generation/absorption on the steady magnetohydrodynamic (MHD) flow and heat transfer of Al2O3-Cu/H2O hybrid nanofluids over a permeable stretching/shrinking wedge. By using similarity transformation techniques, the governing equations of the hybrid nanofluids are transformed into similarity equations. The similarity equations are numerically solved using the MATLAB software's built-in bvp4c package. The findings show that hybrid nanofluids are seen to improve thermal efficiency in comparison to conventional fluid. In relation to heat transfer rate, the increase of magnetic parameters from 0.00 to 0.10 and 0.15 contributes approximately 12.3% and 18.8%, respectively. Meanwhile, as the heat generation parameter increases, the heat transfer rate decreases leading to an inefficient thermal system. The findings of this study are anticipated to contribute to the knowledge base of scientists and researchers in the field.
{"title":"MHD Hybrid Nanofluid Flow Past A Stretching/Shrinking Wedge With Heat Generation/Absorption Impact","authors":"Nurul Amira Zainal, Iskandar Waini, Najiyah Safwa Khashi’ie, Roslinda Nazar, Ioan Pop","doi":"10.37934/cfdl.16.6.146156","DOIUrl":"https://doi.org/10.37934/cfdl.16.6.146156","url":null,"abstract":"Heat transfer is commonly utilized in diverse industrial applications, including the manufacturing of paper, the cooling of electrical devices, and the synthesis of new substances. Hence, this study aims to investigate the effect of heat generation/absorption on the steady magnetohydrodynamic (MHD) flow and heat transfer of Al2O3-Cu/H2O hybrid nanofluids over a permeable stretching/shrinking wedge. By using similarity transformation techniques, the governing equations of the hybrid nanofluids are transformed into similarity equations. The similarity equations are numerically solved using the MATLAB software's built-in bvp4c package. The findings show that hybrid nanofluids are seen to improve thermal efficiency in comparison to conventional fluid. In relation to heat transfer rate, the increase of magnetic parameters from 0.00 to 0.10 and 0.15 contributes approximately 12.3% and 18.8%, respectively. Meanwhile, as the heat generation parameter increases, the heat transfer rate decreases leading to an inefficient thermal system. The findings of this study are anticipated to contribute to the knowledge base of scientists and researchers in the field.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"52 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139603582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gopinathan Sumathi Mini, Prathi Vijaya Kumar, Mohammed Ibrahim Shaik
The study of non-Newtonian nanofluid stagnation point flow over an inclined stretching sheet with thermal radiation effects aims to understand how the fluid's non-Newtonian behavior, nanoparticles, the inclined sheet, and thermal radiation affect velocity profiles, temperature distribution, shear stress, and heat transfer rates. It might be used in materials processing, chemical engineering, and energy systems, where understanding fluid behavior in complicated settings is essential for process optimization and system efficiency. The flow problem is reflected in a set of partial differential equations (PDEs) that serve as the governing equations. After appropriate reformatting into Ordinary Differential Equations (ODEs). Mathematica's NDSolve technique is implemented to do a numerical treatment of the dimensionless equations once they have been translated. The upsides of this strategy lie in its ability to automatically track errors and select the best algorithm. Various dimensionless parameters effects on velocity, temperature, and nanoparticle concentration have been studied, and the results are graphically shown. These include the Casson parameter, Brownian motion and thermophoresis, chemical reaction parameter, thermal radiation, viscous dissipation, and mixed convection parameter. The Casson parameter slows down the velocity and speeds up the distributions of temperature and concentration. The skin friction coefficient increases rapidly with increasing tilt and thermophoretic impact amplitudes. The insights were cross-referenced with previous inquiries in order to validate their veracity. All indications are that it complies rigorously and is highly accurate.
{"title":"Numerical Simulations of Chemically Dissipative MHD Mixed Convective Non-Newtonian Nanofluid Stagnation Point Flow over an Inclined Stretching Sheet with Thermal Radiation Effects","authors":"Gopinathan Sumathi Mini, Prathi Vijaya Kumar, Mohammed Ibrahim Shaik","doi":"10.37934/cfdl.16.5.3758","DOIUrl":"https://doi.org/10.37934/cfdl.16.5.3758","url":null,"abstract":"The study of non-Newtonian nanofluid stagnation point flow over an inclined stretching sheet with thermal radiation effects aims to understand how the fluid's non-Newtonian behavior, nanoparticles, the inclined sheet, and thermal radiation affect velocity profiles, temperature distribution, shear stress, and heat transfer rates. It might be used in materials processing, chemical engineering, and energy systems, where understanding fluid behavior in complicated settings is essential for process optimization and system efficiency. The flow problem is reflected in a set of partial differential equations (PDEs) that serve as the governing equations. After appropriate reformatting into Ordinary Differential Equations (ODEs). Mathematica's NDSolve technique is implemented to do a numerical treatment of the dimensionless equations once they have been translated. The upsides of this strategy lie in its ability to automatically track errors and select the best algorithm. Various dimensionless parameters effects on velocity, temperature, and nanoparticle concentration have been studied, and the results are graphically shown. These include the Casson parameter, Brownian motion and thermophoresis, chemical reaction parameter, thermal radiation, viscous dissipation, and mixed convection parameter. The Casson parameter slows down the velocity and speeds up the distributions of temperature and concentration. The skin friction coefficient increases rapidly with increasing tilt and thermophoretic impact amplitudes. The insights were cross-referenced with previous inquiries in order to validate their veracity. All indications are that it complies rigorously and is highly accurate.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"25 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139534378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Twisted double-tube heat exchangers are promising in improving the heat transfer efficiency on the tube side, decreasing the pressure drop on the shell side, and reducing the size of the equipment. Although offering immense potential, examining heat transfer enhancement techniques inside a heat exchanger. In this study, The thermal-hydraulic characteristics of twisted double-tube heat exchangers fitted with twisted tape inserted have been numerically studied. The Naiver-stokes, energy, and turbulence equations were used to model the fluid flow and heat transfer while the turbulence was with a k- ε model. ANSYS Fluent 23.1 was used to solve the governing equations. The effect of major design elements such as mass flow rate, varied pitches of twisted double tubes and twisted tape inserts was investigated. The hot water was used in the inner tube and the cold water in the outer tube to create a counter-flow apparatus. The Length of the heat exchanger was 1 meter, and the outer and inner diameter was 0.054 and 0.018 m respectively. The thickness of the two tubes was 0.004 m. The twisted ratio of the tubes was tested for =5, 10, and 15 while the twist ratio of the tape was 4, 6, and 8. The findings demonstrated that the utilization of a double twisted tube heat exchanger with a twisted tape insert resulted in enhanced heat transfer in comparison to a plain tube heat exchanger. The numerical analysis revealed that as the twisting ratio drops, the Nusselt number, pressure drop, and overall heat transfer coefficient increase.
{"title":"A Computational Study for Evaluating the Performance of Twisted Double Tube Heat Exchangers Fitted with Twisted Tape","authors":"riyam ali, Khudheyer Salim","doi":"10.37934/cfdl.16.5.2136","DOIUrl":"https://doi.org/10.37934/cfdl.16.5.2136","url":null,"abstract":"Twisted double-tube heat exchangers are promising in improving the heat transfer efficiency on the tube side, decreasing the pressure drop on the shell side, and reducing the size of the equipment. Although offering immense potential, examining heat transfer enhancement techniques inside a heat exchanger. In this study, The thermal-hydraulic characteristics of twisted double-tube heat exchangers fitted with twisted tape inserted have been numerically studied. The Naiver-stokes, energy, and turbulence equations were used to model the fluid flow and heat transfer while the turbulence was with a k- ε model. ANSYS Fluent 23.1 was used to solve the governing equations. The effect of major design elements such as mass flow rate, varied pitches of twisted double tubes and twisted tape inserts was investigated. The hot water was used in the inner tube and the cold water in the outer tube to create a counter-flow apparatus. The Length of the heat exchanger was 1 meter, and the outer and inner diameter was 0.054 and 0.018 m respectively. The thickness of the two tubes was 0.004 m. The twisted ratio of the tubes was tested for =5, 10, and 15 while the twist ratio of the tape was 4, 6, and 8. The findings demonstrated that the utilization of a double twisted tube heat exchanger with a twisted tape insert resulted in enhanced heat transfer in comparison to a plain tube heat exchanger. The numerical analysis revealed that as the twisting ratio drops, the Nusselt number, pressure drop, and overall heat transfer coefficient increase.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"34 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139533889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Samuel Samuel, Rizal Kurnia Praja, Deddy Chrismianto, Muhammad Luqman Hakim, Ahmad Fitriadhy, Aldias Bahatmaka
The deep-v planing hull is designed to operate at high speeds because most of the hull’s weight is supported by the hydrodynamic lift acting on the hull base. Planing hull form characteristics such as deadrise angle, chines, and extended stern significantly affect the ship’s hydrodynamic performance. The addition of the interceptor is an innovation to reduce the total resistance of the ship by controlling the trim angle. However, the form of the ship’s stern is not always the same; thus, it needs to be studied based on the form of the ship’s stern. The extended stern form refers to modifying the hull geometry at the rear, particularly the stern extension beyond its conventional length. This research aimed to analyze the hydrodynamic performance of the interceptor at the extended stern angle. Furthermore, Computational Fluid Dynamics (CFD) simulations were performed to analyze the effect of the extended stern form. A numerical model of the deep-V planing hull with variations of the stern extension was developed, and the flow behavior around the hull was analyzed using CFD techniques. Simulations were conducted under various operating conditions, including different speeds and interceptor strokes. The results indicated that the extended stern's different forms could affect the ship's resistance, trim, and heave. The reduction in resistance was seen at moderate speeds, thereby reducing steep trim angles. The greater the extended stern angle, the more significant the reduction in ship resistance at Fr 0.58 by 26%. Likewise, the combination of interceptor and extended stern experienced a decrease in resistance in the semi-displacement phase with a percentage of 33% resistance, 66% trim, and 47% heave. The interceptor stroke (d) depended on the boundary layer (h). The extended stern with angles of 10°, 20°, and 30° were found to have d/h ratios of 0.38, 0.37, and 0.34. However, it should be noted that extending the stern without interceptors and with interceptors at high speeds could result in a dangerous increase in resistance on high-speed vessel.
{"title":"Advancing Interceptor Design: Analyzing the Impact of Extended Stern Form on Deep-V Planing Hulls","authors":"Samuel Samuel, Rizal Kurnia Praja, Deddy Chrismianto, Muhammad Luqman Hakim, Ahmad Fitriadhy, Aldias Bahatmaka","doi":"10.37934/cfdl.16.5.5977","DOIUrl":"https://doi.org/10.37934/cfdl.16.5.5977","url":null,"abstract":"The deep-v planing hull is designed to operate at high speeds because most of the hull’s weight is supported by the hydrodynamic lift acting on the hull base. Planing hull form characteristics such as deadrise angle, chines, and extended stern significantly affect the ship’s hydrodynamic performance. The addition of the interceptor is an innovation to reduce the total resistance of the ship by controlling the trim angle. However, the form of the ship’s stern is not always the same; thus, it needs to be studied based on the form of the ship’s stern. The extended stern form refers to modifying the hull geometry at the rear, particularly the stern extension beyond its conventional length. This research aimed to analyze the hydrodynamic performance of the interceptor at the extended stern angle. Furthermore, Computational Fluid Dynamics (CFD) simulations were performed to analyze the effect of the extended stern form. A numerical model of the deep-V planing hull with variations of the stern extension was developed, and the flow behavior around the hull was analyzed using CFD techniques. Simulations were conducted under various operating conditions, including different speeds and interceptor strokes. The results indicated that the extended stern's different forms could affect the ship's resistance, trim, and heave. The reduction in resistance was seen at moderate speeds, thereby reducing steep trim angles. The greater the extended stern angle, the more significant the reduction in ship resistance at Fr 0.58 by 26%. Likewise, the combination of interceptor and extended stern experienced a decrease in resistance in the semi-displacement phase with a percentage of 33% resistance, 66% trim, and 47% heave. The interceptor stroke (d) depended on the boundary layer (h). The extended stern with angles of 10°, 20°, and 30° were found to have d/h ratios of 0.38, 0.37, and 0.34. However, it should be noted that extending the stern without interceptors and with interceptors at high speeds could result in a dangerous increase in resistance on high-speed vessel.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139625952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emad Hussein, Farhan Lafta Rashid, Najah Al Maimuri, Ali Basem, Hayder Ibrahim Mohammed
This study evaluates the tsunami forces exerted on a terrestrial structure caused by a collision-induced tsunami. Conventionally, assessing these forces relies on the inundation depth of the colliding tsunami passing without the presence of the terrestrial structure. However, it is essential to consider the inundation depth and incident fluid velocity, as both significantly influence the resulting tsunami forces. In this research, ANSYS Fluent 17.2 is employed to simulate excitation sources using a Defined Function (UDF) code within a C++ framework. The dynamic meshing technique is adopted to replicate the interactions between the bore pressure of the tsunami and an idealised vertical wall structure across three distinct water levels. Computational Fluid Dynamics (CFD) modelling demonstrates the proposed methodology's capability to offer precise impact pressure distributions concerning geographical and temporal aspects. The findings reveal specific instances: at a water depth of 10 m, the maximum Froude number is attained at 3.5 and 6.9 seconds, corresponding to a maximum pressure value of 3.9x105 Pa at 3.85 seconds for a water flow velocity of 20 m/sec. Similarly, for a water depth of 12 m, the most significant Froude number is observed at 3.95 and 6.9 seconds, with a peak pressure value of 1.8x105 Pa at 4.6 seconds, associated with a water flow velocity of 15 m/s. Additionally, at a water depth of 14 m, the maximum Froude number is reached at 4.95 and 7.1 seconds, accompanied by a maximum pressure value of 7.4x104 Pa at 4.85 seconds for a water flow velocity of 10 m/s.
{"title":"Numerical Assessment of Tsunami Forces on Vertical Wall Structures: Impact of Inundation Depth and Incident Fluid Velocity","authors":"Emad Hussein, Farhan Lafta Rashid, Najah Al Maimuri, Ali Basem, Hayder Ibrahim Mohammed","doi":"10.37934/cfdl.16.5.7890","DOIUrl":"https://doi.org/10.37934/cfdl.16.5.7890","url":null,"abstract":"This study evaluates the tsunami forces exerted on a terrestrial structure caused by a collision-induced tsunami. Conventionally, assessing these forces relies on the inundation depth of the colliding tsunami passing without the presence of the terrestrial structure. However, it is essential to consider the inundation depth and incident fluid velocity, as both significantly influence the resulting tsunami forces. In this research, ANSYS Fluent 17.2 is employed to simulate excitation sources using a Defined Function (UDF) code within a C++ framework. The dynamic meshing technique is adopted to replicate the interactions between the bore pressure of the tsunami and an idealised vertical wall structure across three distinct water levels. Computational Fluid Dynamics (CFD) modelling demonstrates the proposed methodology's capability to offer precise impact pressure distributions concerning geographical and temporal aspects. The findings reveal specific instances: at a water depth of 10 m, the maximum Froude number is attained at 3.5 and 6.9 seconds, corresponding to a maximum pressure value of 3.9x105 Pa at 3.85 seconds for a water flow velocity of 20 m/sec. Similarly, for a water depth of 12 m, the most significant Froude number is observed at 3.95 and 6.9 seconds, with a peak pressure value of 1.8x105 Pa at 4.6 seconds, associated with a water flow velocity of 15 m/s. Additionally, at a water depth of 14 m, the maximum Froude number is reached at 4.95 and 7.1 seconds, accompanied by a maximum pressure value of 7.4x104 Pa at 4.85 seconds for a water flow velocity of 10 m/s.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139626421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-11DOI: 10.37934/cfdl.16.5.121134
Ismail, Rinawati, Imam Muzaki
This study evaluates the tsunami forces exerted on a terrestrial structure caused by a collision-induced tsunami. Conventionally, assessing these forces relies on the inundation depth of the colliding tsunami passing without the presence of the terrestrial structure. However, it is essential to consider the inundation depth and incident fluid velocity, as both significantly influence the resulting tsunami forces. In this research, ANSYS Fluent 17.2 is employed to simulate excitation sources using a Defined Function (UDF) code within a C++ framework. The dynamic meshing technique is adopted to replicate the interactions between the bore pressure of the tsunami and an idealised vertical wall structure across three distinct water levels. Computational Fluid Dynamics (CFD) modelling demonstrates the proposed methodology's capability to offer precise impact pressure distributions concerning geographical and temporal aspects. The findings reveal specific instances: at a water depth of 10 m, the maximum Froude number is attained at 3.5 and 6.9 seconds, corresponding to a maximum pressure value of 3.9x105 Pa at 3.85 seconds for a water flow velocity of 20 m/sec. Similarly, for a water depth of 12 m, the most significant Froude number is observed at 3.95 and 6.9 seconds, with a peak pressure value of 1.8x105 Pa at 4.6 seconds, associated with a water flow velocity of 15 m/s. Additionally, at a water depth of 14 m, the maximum Froude number is reached at 4.95 and 7.1 seconds, accompanied by a maximum pressure value of 7.4x104 Pa at 4.85 seconds for a water flow velocity of 10 m/s.
{"title":"Investigation of Vertical Axis Wind Turbine Performance with Savonius Rotor on Air Ejector Dimensions using Computational Fluid Dynamics","authors":"Ismail, Rinawati, Imam Muzaki","doi":"10.37934/cfdl.16.5.121134","DOIUrl":"https://doi.org/10.37934/cfdl.16.5.121134","url":null,"abstract":"This study evaluates the tsunami forces exerted on a terrestrial structure caused by a collision-induced tsunami. Conventionally, assessing these forces relies on the inundation depth of the colliding tsunami passing without the presence of the terrestrial structure. However, it is essential to consider the inundation depth and incident fluid velocity, as both significantly influence the resulting tsunami forces. In this research, ANSYS Fluent 17.2 is employed to simulate excitation sources using a Defined Function (UDF) code within a C++ framework. The dynamic meshing technique is adopted to replicate the interactions between the bore pressure of the tsunami and an idealised vertical wall structure across three distinct water levels. Computational Fluid Dynamics (CFD) modelling demonstrates the proposed methodology's capability to offer precise impact pressure distributions concerning geographical and temporal aspects. The findings reveal specific instances: at a water depth of 10 m, the maximum Froude number is attained at 3.5 and 6.9 seconds, corresponding to a maximum pressure value of 3.9x105 Pa at 3.85 seconds for a water flow velocity of 20 m/sec. Similarly, for a water depth of 12 m, the most significant Froude number is observed at 3.95 and 6.9 seconds, with a peak pressure value of 1.8x105 Pa at 4.6 seconds, associated with a water flow velocity of 15 m/s. Additionally, at a water depth of 14 m, the maximum Froude number is reached at 4.95 and 7.1 seconds, accompanied by a maximum pressure value of 7.4x104 Pa at 4.85 seconds for a water flow velocity of 10 m/s.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"22 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139534412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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