Pub Date : 2026-01-02DOI: 10.1016/j.apples.2025.100288
Mohan Anand, Banothu Gnaneshwarii
A variant of Stokes’ second problem, namely the flow of a pool of liquid between two plates with the bottom plate oscillating, is studied for a novel shear thinning fluid model for paint. The governing equation is obtained using the semi-inverse approach. The governing equation is solved numerically, subject to the appropriate initial and boundary conditions. The cases of bottom plate subject to oscillatory velocity and oscillatory shear stress are studied. The results are qualitatively similar: the fluid damps the oscillations and introduces a phase shift, the extent of each depending on the distance from the plate. A parameter study is conducted for the case of the bottom plate being subject to oscillatory velocity. Increasing the amplitude of oscillations increases the maximum velocity close to the plate, but the effect diminishes with increasing amplitude. On the other hand, increasing the frequency decreases the maximum velocity close to the plate. The effect of the material parameters of paint on the maximum velocity close to the plate, although counterintuitive, matches what is expected for shear thinning fluids.
{"title":"A variant of Stokes’ second problem for a new shear thinning model for paint","authors":"Mohan Anand, Banothu Gnaneshwarii","doi":"10.1016/j.apples.2025.100288","DOIUrl":"10.1016/j.apples.2025.100288","url":null,"abstract":"<div><div>A variant of Stokes’ second problem, namely the flow of a pool of liquid between two plates with the bottom plate oscillating, is studied for a novel shear thinning fluid model for paint. The governing equation is obtained using the semi-inverse approach. The governing equation is solved numerically, subject to the appropriate initial and boundary conditions. The cases of bottom plate subject to oscillatory velocity and oscillatory shear stress are studied. The results are qualitatively similar: the fluid damps the oscillations and introduces a phase shift, the extent of each depending on the distance from the plate. A parameter study is conducted for the case of the bottom plate being subject to oscillatory velocity. Increasing the amplitude of oscillations increases the maximum velocity close to the plate, but the effect diminishes with increasing amplitude. On the other hand, increasing the frequency decreases the maximum velocity close to the plate. The effect of the material parameters of paint on the maximum velocity close to the plate, although counterintuitive, matches what is expected for shear thinning fluids.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100288"},"PeriodicalIF":2.1,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038027","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 : 2025-12-30DOI: 10.1016/j.apples.2025.100291
Brinda Halambi , B.N. Hanumagowda , Ali B.M. Ali , C.P. Gowthami , T. Saikiran , D.V. Jayamadhavachari , Jagadish V. Tawade , Rakhmonjon Akhmadjonov , M. Ijaz Khan
This comprehensive study investigates the combined effects of the interplay between an externally applied transverse magnetic field and the coupled flows in the squeeze film between porous elliptical plates, including the influence of slip velocity. The model employs the Stokes couple stress fluid theory to represent the effects of lubricant additives, and applies Cowling's theory to the electrically conductive fluid in the presence of a transverse magnetic field. Darcy's law is employed to model the flow through the porous media. The modified Reynolds equations incorporate these key effects, and detailed expressions for various squeeze film characteristics are derived. The novelty of the present work lies in the simultaneous inclusion of magneto-hydrodynamic, couple stress, and slip velocity effects in a porous elliptical geometry, an integration rarely addressed in previous studies. The results indicate that non-porous plates exhibit higher pressure generation compared to porous ones, and the squeeze film performance declines with increasing porosity. The results indicate that non-porous plates exhibit higher pressure generation compared to porous ones, and the squeeze film performance declines with increasing porosity. Conversely, the Lorentz force and couple stress, are found to enhance the lubrication performance compared to classical cases without these factors. These effects are more marked for smaller values of permeability and slip velocity . These valuable insights offer important guidance for the design of squeeze film lubrication systems utilizing porous elliptical plates subjected to transverse magnetic fields.
{"title":"A comprehensive investigation of squeeze film lubrication in porous elliptical plates: Analyzin the influences of magneto-hydrodynamics, couple stress and slip velocity","authors":"Brinda Halambi , B.N. Hanumagowda , Ali B.M. Ali , C.P. Gowthami , T. Saikiran , D.V. Jayamadhavachari , Jagadish V. Tawade , Rakhmonjon Akhmadjonov , M. Ijaz Khan","doi":"10.1016/j.apples.2025.100291","DOIUrl":"10.1016/j.apples.2025.100291","url":null,"abstract":"<div><div>This comprehensive study investigates the combined effects of the interplay between an externally applied transverse magnetic field and the coupled flows in the squeeze film between porous elliptical plates, including the influence of slip velocity. The model employs the Stokes couple stress fluid theory to represent the effects of lubricant additives, and applies Cowling's theory to the electrically conductive fluid in the presence of a transverse magnetic field. Darcy's law is employed to model the flow through the porous media. The modified Reynolds equations incorporate these key effects, and detailed expressions for various squeeze film characteristics are derived. The novelty of the present work lies in the simultaneous inclusion of magneto-hydrodynamic, couple stress, and slip velocity effects in a porous elliptical geometry, an integration rarely addressed in previous studies. The results indicate that non-porous plates exhibit higher pressure generation compared to porous ones, and the squeeze film performance declines with increasing porosity. The results indicate that non-porous plates exhibit higher pressure generation compared to porous ones, and the squeeze film performance declines with increasing porosity. Conversely, the Lorentz force and couple stress, are found to enhance the lubrication performance compared to classical cases without these factors. These effects are more marked for smaller values of permeability <span><math><mi>ψ</mi></math></span> and slip velocity <span><math><mi>s</mi></math></span>. These valuable insights offer important guidance for the design of squeeze film lubrication systems utilizing porous elliptical plates subjected to transverse magnetic fields.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100291"},"PeriodicalIF":2.1,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925923","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}
The design, development, and validation of a self-aspirated two-layer porous radiant burner (PRB) for high-efficiency biogas cookstoves meant for off-grid and resource-constrained households are presented in this study. To improve flame stability, encourage air-fuel mixing, and facilitate passive jet-ejector entrainment without the need for external blowers, the burner combines a silicon carbide (SiC) combustion zone with a cast-iron preheating zone. Thermal efficiencies of 51–59% were found through experimental evaluation using water-boiling and emission tests. This performance was close to forced-air PRB performance (53–61%) and exceeded that of conventional biogas burners (46–54%). Emissions of nitrogen oxides (NOₓ) and carbon monoxide (CO) decreased by 29.6% and 79.4%, respectively, indicating cleaner and more thorough combustion. The system's performance parity was confirmed by comparative benchmarking with current porous burner technologies; it achieved 97% efficiency equivalency to forced-air PRBs while removing the need for auxiliary power. Environmental analysis showed an annual reduction of about 12 kg CO₂-eq emissions per household, while economic analysis showed a payback period of about 11 months due to biogas savings of about 9%. Thus, the self-aspired PRB offers a technically sound, financially viable, and ecologically advantageous solution for the sustainable use of biogas. These results transform the design from a proof-of-concept into a verified, ready-to-use candidate for implementation in clean cooking initiatives in Ethiopia and other developing nations.
{"title":"A self-aspirated two-layer porous radiant burner for high-efficiency biogas cookstoves: Experimental performance and emission analysis","authors":"Yared Yalew Temesgen , Kamil Dino Adem , Kumlachew Yeneneh","doi":"10.1016/j.apples.2025.100289","DOIUrl":"10.1016/j.apples.2025.100289","url":null,"abstract":"<div><div>The design, development, and validation of a self-aspirated two-layer porous radiant burner (PRB) for high-efficiency biogas cookstoves meant for off-grid and resource-constrained households are presented in this study. To improve flame stability, encourage air-fuel mixing, and facilitate passive jet-ejector entrainment without the need for external blowers, the burner combines a silicon carbide (SiC) combustion zone with a cast-iron preheating zone. Thermal efficiencies of 51–59% were found through experimental evaluation using water-boiling and emission tests. This performance was close to forced-air PRB performance (53–61%) and exceeded that of conventional biogas burners (46–54%). Emissions of nitrogen oxides (NOₓ) and carbon monoxide (CO) decreased by 29.6% and 79.4%, respectively, indicating cleaner and more thorough combustion. The system's performance parity was confirmed by comparative benchmarking with current porous burner technologies; it achieved 97% efficiency equivalency to forced-air PRBs while removing the need for auxiliary power. Environmental analysis showed an annual reduction of about 12 kg CO₂-eq emissions per household, while economic analysis showed a payback period of about 11 months due to biogas savings of about 9%. Thus, the self-aspired PRB offers a technically sound, financially viable, and ecologically advantageous solution for the sustainable use of biogas. These results transform the design from a proof-of-concept into a verified, ready-to-use candidate for implementation in clean cooking initiatives in Ethiopia and other developing nations.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100289"},"PeriodicalIF":2.1,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977221","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}
Optimizing heat transfer from backward-facing step (BFS) flows is important for thermal management in applications like solar air heaters, compact heat exchangers, and cooling devices for electronics. This study provides a detailed numerical analysis of how flow diverters can improve the thermal performance of a BFS channel with semi-circular cavities on the bottom wall, using water as the working fluid. It examines two-dimensional, incompressible, steady-state laminar flow with forced convection at low Reynolds numbers equal to 100 and 200. The analysis focuses into the effects of three strategically placed splitter plates, each positioned above the circular cavity sections, with the plates angled in 15° increments. Key features such as recirculation vortices, reattachment points, and the thermal boundary layer were examined to explore the hydrodynamics and heat transfer characteristics. The position of the splitter plate alters the local u velocity significantly. The thermal performance shows favorable results, but the friction factor is also increased when placing splitter plates. The results show that almost all splitter plate configurations improve heat transfer, while certain scenarios, such as plates at 0° at Re = 200, do not enhance it compared to the base case without splitter plates. The average Nusselt number increases by up to 33 % at Re = 100 and 46 % at Re = 200 for the best plate configurations. The 30° splitter plate angle was found to be the optimal setup for maximizing thermal performance. Flow visualization shows that angled plates direct the mainstream flow toward cavity sections, improving fluid mixing and disrupting the thermal boundary layers. The presence of secondary vortex structures behind the splitter plates causes a significant effect on local heat transfer, with local Nusselt number peaks occurring at the cavity's singular points.
{"title":"Numerical analysis of heat transfer enhancement in step-aside cavities with splitter plate assistance","authors":"Amogh Ashwin Thondavadi , Ansh Parihar , A․Senthil Kumar , P․Rajesh Kanna","doi":"10.1016/j.apples.2025.100287","DOIUrl":"10.1016/j.apples.2025.100287","url":null,"abstract":"<div><div>Optimizing heat transfer from backward-facing step (BFS) flows is important for thermal management in applications like solar air heaters, compact heat exchangers, and cooling devices for electronics. This study provides a detailed numerical analysis of how flow diverters can improve the thermal performance of a BFS channel with semi-circular cavities on the bottom wall, using water as the working fluid. It examines two-dimensional, incompressible, steady-state laminar flow with forced convection at low Reynolds numbers equal to 100 and 200. The analysis focuses into the effects of three strategically placed splitter plates, each positioned above the circular cavity sections, with the plates angled in 15° increments. Key features such as recirculation vortices, reattachment points, and the thermal boundary layer were examined to explore the hydrodynamics and heat transfer characteristics. The position of the splitter plate alters the local u velocity significantly. The thermal performance shows favorable results, but the friction factor is also increased when placing splitter plates. The results show that almost all splitter plate configurations improve heat transfer, while certain scenarios, such as plates at 0° at Re = 200, do not enhance it compared to the base case without splitter plates. The average Nusselt number increases by up to 33 % at Re = 100 and 46 % at Re = 200 for the best plate configurations. The 30° splitter plate angle was found to be the optimal setup for maximizing thermal performance. Flow visualization shows that angled plates direct the mainstream flow toward cavity sections, improving fluid mixing and disrupting the thermal boundary layers. The presence of secondary vortex structures behind the splitter plates causes a significant effect on local heat transfer, with local Nusselt number peaks occurring at the cavity's singular points.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100287"},"PeriodicalIF":2.1,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925920","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}
The influence of fixed and movable Gurney flaps on the aerodynamic characteristics of various devices, including flapping airfoils and vertical and horizontal axis turbines, has been widely studied. This paper presents a novel idea of Deformable Gurney Flap (DGF) combined with a Droop-Nose Leading-Edge (DNLE), which aims to enhance the output power of flapping airfoils in a reversed D configuration. The core mechanism involves actuating the DNLE to rapidly increase the drag profile with a deflection velocity (i.e. twice that of the main airfoil) thereby maximizing the power extracted via horizontal motion, . Crucially, the DNLE is deployed only when the main airfoil's motion aligns with the direction of the resultant drag force. The primary advantage of the DGF-DNLE architecture is its ability to provide complete control over the flap's aerodynamic influence throughout the complex flapping cycle. The DGF's capacity for controlled expansion and contraction allows for timely and precise adjustments to the pressure distribution, thereby optimizing the integrated lift and drag coefficients. A comprehensive numerical analysis, conducted using a two-dimensional transient simulation with an adapted dynamic mesh, demonstrated a 21 % increase in the overall output power compared to the baseline configuration.
{"title":"How deformable Gurney flaps combined to droop nose leading edge affecting the output power of flapping wind turbine?","authors":"Charaf-Eddine Bensaci , Mohamed Taher Bouzaher , Khaoula Ikhlef , Ammar Zeghloul , Abdelhamid Bouhelal","doi":"10.1016/j.apples.2025.100286","DOIUrl":"10.1016/j.apples.2025.100286","url":null,"abstract":"<div><div>The influence of fixed and movable Gurney flaps on the aerodynamic characteristics of various devices, including flapping airfoils and vertical and horizontal axis turbines, has been widely studied. This paper presents a novel idea of Deformable Gurney Flap (DGF) combined with a Droop-Nose Leading-Edge (DNLE), which aims to enhance the output power of flapping airfoils in a reversed D configuration. The core mechanism involves actuating the DNLE to rapidly increase the drag profile with a deflection velocity (i.e. twice that of the main airfoil) thereby maximizing the power extracted via horizontal motion, <span><math><mrow><msub><mi>P</mi><mi>x</mi></msub><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow></mrow></math></span>. Crucially, the DNLE is deployed only when the main airfoil's motion aligns with the direction of the resultant drag force. The primary advantage of the DGF-DNLE architecture is its ability to provide complete control over the flap's aerodynamic influence throughout the complex flapping cycle. The DGF's capacity for controlled expansion and contraction allows for timely and precise adjustments to the pressure distribution, thereby optimizing the integrated lift and drag coefficients. A comprehensive numerical analysis, conducted using a two-dimensional transient simulation with an adapted dynamic mesh, demonstrated a 21 % increase in the overall output power compared to the baseline configuration.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100286"},"PeriodicalIF":2.1,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925937","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 : 2025-12-15DOI: 10.1016/j.apples.2025.100285
Nguyen Thi Anh , Tran Thanh Tung
Thin-walled components are widely used in aerospace and automotive applications due to their high stiffness-to-weight ratio but are highly susceptible to deformation during milling, resulting in dimensional errors and reduced surface quality. In this study, a three-dimensional finite element model (FEM) was developed and experimentally validated to investigate the force–deflection behavior of a thin-walled aluminum workpiece with dimensions 130 × 2.5 × 60 mm. The experimental tests were conducted on a HAAS VF-2 CNC machining center using a 12 mm, 4-flute end mill, while the FEM was constructed with refined meshing and boundary conditions replicating the clamping and cutting parameters. Cutting force predictions in the X, Y, and Z directions showed good agreement with experimental measurements, with minor discrepancies attributed to fixture compliance and tool–workpiece contact assumptions. Displacement fields and time-history responses revealed progressive wall deflection, with maximum values of approximately 0.06 mm occurring at the free edge, consistent with experimental observations. The validated model demonstrates that FEM can effectively capture both force and deflection trends in thin-wall milling, providing a reliable framework for process planning, parameter optimization, and machining error control in precision manufacturing.
薄壁部件由于其高刚度重量比而广泛应用于航空航天和汽车应用，但在铣削过程中极易变形，导致尺寸误差和表面质量降低。针对尺寸为130 × 2.5 × 60 mm的薄壁铝件，建立了三维有限元模型并进行了实验验证。在HAAS VF-2数控加工中心上，利用一架12 mm 4槽立铣刀进行了实验测试，并建立了模拟夹紧和切削参数的精细化网格和边界条件的有限元模型。在X、Y和Z方向上的切削力预测与实验测量结果显示出良好的一致性，由于夹具顺应性和工具-工件接触假设，存在较小的差异。位移场和时程响应显示出渐进式壁面挠度，在自由边缘处出现的最大值约为0.06 mm，与实验观察结果一致。验证模型表明，有限元法可以有效地捕捉薄壁铣削过程中的力和挠度变化趋势，为精密制造中的工艺规划、参数优化和加工误差控制提供了可靠的框架。
{"title":"Development and validation of finite element model of milling thin-walled part","authors":"Nguyen Thi Anh , Tran Thanh Tung","doi":"10.1016/j.apples.2025.100285","DOIUrl":"10.1016/j.apples.2025.100285","url":null,"abstract":"<div><div>Thin-walled components are widely used in aerospace and automotive applications due to their high stiffness-to-weight ratio but are highly susceptible to deformation during milling, resulting in dimensional errors and reduced surface quality. In this study, a three-dimensional finite element model (FEM) was developed and experimentally validated to investigate the force–deflection behavior of a thin-walled aluminum workpiece with dimensions 130 × 2.5 × 60 mm. The experimental tests were conducted on a HAAS VF-2 CNC machining center using a 12 mm, 4-flute end mill, while the FEM was constructed with refined meshing and boundary conditions replicating the clamping and cutting parameters. Cutting force predictions in the X, Y, and Z directions showed good agreement with experimental measurements, with minor discrepancies attributed to fixture compliance and tool–workpiece contact assumptions. Displacement fields and time-history responses revealed progressive wall deflection, with maximum values of approximately 0.06 mm occurring at the free edge, consistent with experimental observations. The validated model demonstrates that FEM can effectively capture both force and deflection trends in thin-wall milling, providing a reliable framework for process planning, parameter optimization, and machining error control in precision manufacturing.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100285"},"PeriodicalIF":2.1,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797792","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 : 2025-12-15DOI: 10.1016/j.apples.2025.100284
Wahad Ur Rahman , Farid Ullah Khan
This study discusses a hybrid flow energy harvester that integrates electromagnetic (EM) and piezoelectric (PE) effects to convert fluid flow into electricity, thereby powering an Internet of Things (IoT) system for pipeline monitoring. The prototype featured an unimorph circular piezoelectric plate attached to an adjustable housing, with three cylindrical magnets fixed at the center of the brass side, and a wound coil positioned in an adjustable coil holder above the magnets. Laboratory tests showed that the harvester achieved a maximum RMS load voltage of 2.33 V at an optimal load of 27 kΩ from the PE component and 169 mV at an optimal load of 200 Ω from the EM component. The PE part generated 201 µW of peak load power, whereas the EM part produced 144 µW at a flow pressure of 2.9 kPa and a flow rate of 11.08 l/s. When combined with a rectifier circuit, it produced up to 7.68 V DC from the PE section and 3.15 V DC from the EM section under the same conditions. Additionally, at these flow rates, the maximum DC power output was 169 µW from the piezoelectric element at a 90 kΩ load resistance and 125 µW from the EM element at 9.5 kΩ, respectively. Over 336 min, this device effectively charged the power backup from 1.11 to 4.31 V, demonstrating its practical applicability. A comparative analysis shows that this innovative hybrid harvester outperforms existing flow energy harvesters in both output power and energy efficiency.
{"title":"Hybrid piezoelectric–electromagnetic flow energy harvester for self-powered IoT-based pipeline monitoring systems","authors":"Wahad Ur Rahman , Farid Ullah Khan","doi":"10.1016/j.apples.2025.100284","DOIUrl":"10.1016/j.apples.2025.100284","url":null,"abstract":"<div><div>This study discusses a hybrid flow energy harvester that integrates electromagnetic (EM) and piezoelectric (PE) effects to convert fluid flow into electricity, thereby powering an Internet of Things (IoT) system for pipeline monitoring. The prototype featured an unimorph circular piezoelectric plate attached to an adjustable housing, with three cylindrical magnets fixed at the center of the brass side, and a wound coil positioned in an adjustable coil holder above the magnets. Laboratory tests showed that the harvester achieved a maximum RMS load voltage of 2.33 V at an optimal load of 27 kΩ from the PE component and 169 mV at an optimal load of 200 Ω from the EM component. The PE part generated 201 µW of peak load power, whereas the EM part produced 144 µW at a flow pressure of 2.9 kPa and a flow rate of 11.08 l/s. When combined with a rectifier circuit, it produced up to 7.68 V DC from the PE section and 3.15 V DC from the EM section under the same conditions. Additionally, at these flow rates, the maximum DC power output was 169 µW from the piezoelectric element at a 90 kΩ load resistance and 125 µW from the EM element at 9.5 kΩ, respectively. Over 336 min, this device effectively charged the power backup from 1.11 to 4.31 V, demonstrating its practical applicability. A comparative analysis shows that this innovative hybrid harvester outperforms existing flow energy harvesters in both output power and energy efficiency.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100284"},"PeriodicalIF":2.1,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797793","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 : 2025-12-14DOI: 10.1016/j.apples.2025.100283
Hossein Sohrabzadeh Anzani, Sameh Ahmed Kantoush, Sohei Kobayashi
Accurate estimation of Manning’s roughness coefficient (n) is critical for modeling open-channel flow dynamics, particularly in steep-gradient streams where conventional empirical methods often fail to represent complex resistance mechanisms. This study enhances the understanding of hydraulic resistance through controlled experiments conducted in a 7-m Plexiglas flume at the Ujigawa Hydraulic Laboratory, Kyoto University. Two experimental conditions were examined: a smooth channel, serving as a reference case, and a channel with one-sided wart-type roughness installed at 20-cm intervals. Measurements included velocity profiles and energy dissipation patterns, with emphasis on the cumulative downstream effects of roughness. The rough-bed condition exhibited skimming flow and localized turbulence, captured through three-dimensional velocity measurements and heatmap analyses. This is the first controlled study of one-sided (asymmetric) hemispherical wart-type roughness in steep open channels (S/K ≈ 5.71, wake-interference regime). Unlike symmetric roughness, the unilateral arrangement generates lateral secondary currents and a cumulative downstream increase of Manning’s n by up to 40 %. Statistical testing confirmed that roughness-induced differences were highly significant (p = 0.000741), while sensitivity analysis demonstrated the strong dependence of n on roughness density. The findings underscore the necessity of accounting for spatially variable roughness in hydraulic models.
{"title":"Influence of one-side wart-type roughness on flow dynamics in open channels: experimental and statistical analysis","authors":"Hossein Sohrabzadeh Anzani, Sameh Ahmed Kantoush, Sohei Kobayashi","doi":"10.1016/j.apples.2025.100283","DOIUrl":"10.1016/j.apples.2025.100283","url":null,"abstract":"<div><div>Accurate estimation of Manning’s roughness coefficient (<em>n</em>) is critical for modeling open-channel flow dynamics, particularly in steep-gradient streams where conventional empirical methods often fail to represent complex resistance mechanisms. This study enhances the understanding of hydraulic resistance through controlled experiments conducted in a 7-m Plexiglas flume at the Ujigawa Hydraulic Laboratory, Kyoto University. Two experimental conditions were examined: a smooth channel, serving as a reference case, and a channel with one-sided wart-type roughness installed at 20-cm intervals. Measurements included velocity profiles and energy dissipation patterns, with emphasis on the cumulative downstream effects of roughness. The rough-bed condition exhibited skimming flow and localized turbulence, captured through three-dimensional velocity measurements and heatmap analyses. This is the first controlled study of one-sided (asymmetric) hemispherical wart-type roughness in steep open channels (<em>S</em>/<em>K</em> ≈ 5.71, wake-interference regime). Unlike symmetric roughness, the unilateral arrangement generates lateral secondary currents and a cumulative downstream increase of Manning’s n by up to 40 %. Statistical testing confirmed that roughness-induced differences were highly significant (<em>p</em> = 0.000741), while sensitivity analysis demonstrated the strong dependence of <em>n</em> on roughness density. The findings underscore the necessity of accounting for spatially variable roughness in hydraulic models.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100283"},"PeriodicalIF":2.1,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797790","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 : 2025-12-09DOI: 10.1016/j.apples.2025.100282
Ioannis Tselios, Pantelis G. Nikolakopoulos
This paper presents a novel AI-based framework for the design optimization of shafts made of Functionally Graded Materials (FGMs), along with a detailed vibration analysis for multiple conditions. Functionally Graded Material (FGM) shafts combine the high-temperature resistance of ceramics with the toughness of metals, making them valuable in high-performance rotating machinery. However, their dynamic behavior becomes significantly more complex in the presence of cracks, thermal gradients, and material gradation. In this work, a comprehensive numerical study of the vibration response of unbalanced FGM shafts with a transverse breathing crack is conducted across different material gradations, thermal gradients, and rotational speeds. To reduce the computational cost of the design optimization process, an integrated Artificial Intelligence framework combining Artificial Neural Networks (ANNs) and Genetic Algorithms (GAs) is introduced. The ANN serves as an accurate surrogate model for predicting key performance indicators, including critical speed, static deflection, weight, and effective fracture toughness, while the GA efficiently explores the design space for optimal shaft configurations. The results highlight the influence of FGM gradation and thermal loading on the vibrational characteristics of cracked rotors and demonstrate that the proposed ANN-GA framework delivers excellent multi-objective optimization performance with high predictive accuracy. This work provides both deeper insight into the dynamics of cracked FGM shafts and a computationally efficient tool for their design optimization, supporting more reliable rotor-bearing systems.
{"title":"Vibration analysis of a functionally Graded cracked shaft system and AI-based design optimization","authors":"Ioannis Tselios, Pantelis G. Nikolakopoulos","doi":"10.1016/j.apples.2025.100282","DOIUrl":"10.1016/j.apples.2025.100282","url":null,"abstract":"<div><div>This paper presents a novel AI-based framework for the design optimization of shafts made of Functionally Graded Materials (FGMs), along with a detailed vibration analysis for multiple conditions. Functionally Graded Material (FGM) shafts combine the high-temperature resistance of ceramics with the toughness of metals, making them valuable in high-performance rotating machinery. However, their dynamic behavior becomes significantly more complex in the presence of cracks, thermal gradients, and material gradation. In this work, a comprehensive numerical study of the vibration response of unbalanced FGM shafts with a transverse breathing crack is conducted across different material gradations, thermal gradients, and rotational speeds. To reduce the computational cost of the design optimization process, an integrated Artificial Intelligence framework combining Artificial Neural Networks (ANNs) and Genetic Algorithms (GAs) is introduced. The ANN serves as an accurate surrogate model for predicting key performance indicators, including critical speed, static deflection, weight, and effective fracture toughness, while the GA efficiently explores the design space for optimal shaft configurations. The results highlight the influence of FGM gradation and thermal loading on the vibrational characteristics of cracked rotors and demonstrate that the proposed ANN-GA framework delivers excellent multi-objective optimization performance with high predictive accuracy. This work provides both deeper insight into the dynamics of cracked FGM shafts and a computationally efficient tool for their design optimization, supporting more reliable rotor-bearing systems.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100282"},"PeriodicalIF":2.1,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797791","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 : 2025-12-06DOI: 10.1016/j.apples.2025.100281
Jian Wang , Chunlei Jiang , Guanglin Li , Dongjian Su , Hao Wang , Ruyi Tao
Deployable spacecraft have been widely used, while the motion state under the disturbance is still unknown. A test device is designed to simulate the motion of deployable spacecraft in this paper, and the ballistic characteristics of solid thruster are tested. The test results show that the total impulse deviation of the solid thruster can be effectively reduced by controlling the propellant mass, but the spacecraft would still produce a large precession angle and precession angular rate. The influence of launch disturbance and deployment disturbance on the spacecraft is larger than that of spinning thruster deviation. The ratio between the transverse moment of inertia and the axial moment of inertia should be increased as much as possible during the design of the spacecraft, otherwise a small disturbance would produce a large precession angle. The test results have certain reference significance for the study of the spacecraft micro-motion.
{"title":"Study on influence of initial deviation on motion attitude of spacecraft","authors":"Jian Wang , Chunlei Jiang , Guanglin Li , Dongjian Su , Hao Wang , Ruyi Tao","doi":"10.1016/j.apples.2025.100281","DOIUrl":"10.1016/j.apples.2025.100281","url":null,"abstract":"<div><div>Deployable spacecraft have been widely used, while the motion state under the disturbance is still unknown. A test device is designed to simulate the motion of deployable spacecraft in this paper, and the ballistic characteristics of solid thruster are tested. The test results show that the total impulse deviation of the solid thruster can be effectively reduced by controlling the propellant mass, but the spacecraft would still produce a large precession angle and precession angular rate. The influence of launch disturbance and deployment disturbance on the spacecraft is larger than that of spinning thruster deviation. The ratio between the transverse moment of inertia and the axial moment of inertia should be increased as much as possible during the design of the spacecraft, otherwise a small disturbance would produce a large precession angle. The test results have certain reference significance for the study of the spacecraft micro-motion.</div></div>","PeriodicalId":72251,"journal":{"name":"Applications in engineering science","volume":"25 ","pages":"Article 100281"},"PeriodicalIF":2.1,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748997","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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