This work concisely investigates unsteady magnetohydrodynamic (MHD) convection of nanofluids within a confined enclosure subjected to an inclined magnetic field and internal heat generation or absorption. Utilizing the Buongiorno model, which incorporates thermophoresis and Brownian motion, the coupled mass, momentum, energy, and nanoparticle concentration equations are solved using the finite element method (FEM), which is an efficient procedure for solving two-dimensional thermal problems. Parametric analysis is carried out over Reynolds, Hartmann, and Schmidt numbers, magnetic field inclination angle, and heat source/sink strength. Results indicate that higher Reynolds numbers significantly enhance fluid flow and the mean Nusselt number. Increasing Hartmann numbers suppresses convection but yields modest improvements in heat transfer. A magnetic inclination of 30° maximizes heat transfer efficiency. Elevated Schmidt numbers enhance momentum transport but decrease thermal efficiency due to reduced mass diffusivity. Internal heat generation significantly enhances heat transfer performance, resulting in nearly a 300 % increase in Nusselt numbers at the base wall under conditions of heat generation. These findings offer valuable insights into the dynamic coupling of nanoparticle transport, magnetic control, and thermal regulation in unsteady MHD systems.
{"title":"Thermomagnetic unsteady convection of nanofluid flow in an inclined-field cavity","authors":"Majdeddin Emad , Payam Jalili , Bahram Jalili , Davood Domiri Ganji","doi":"10.1016/j.dynatmoce.2025.101617","DOIUrl":"10.1016/j.dynatmoce.2025.101617","url":null,"abstract":"<div><div>This work concisely investigates unsteady magnetohydrodynamic (MHD) convection of nanofluids within a confined enclosure subjected to an inclined magnetic field and internal heat generation or absorption. Utilizing the Buongiorno model, which incorporates thermophoresis and Brownian motion, the coupled mass, momentum, energy, and nanoparticle concentration equations are solved using the finite element method (FEM), which is an efficient procedure for solving two-dimensional thermal problems. Parametric analysis is carried out over Reynolds, Hartmann, and Schmidt numbers, magnetic field inclination angle, and heat source/sink strength. Results indicate that higher Reynolds numbers significantly enhance fluid flow and the mean Nusselt number. Increasing Hartmann numbers suppresses convection but yields modest improvements in heat transfer. A magnetic inclination of 30° maximizes heat transfer efficiency. Elevated Schmidt numbers enhance momentum transport but decrease thermal efficiency due to reduced mass diffusivity. Internal heat generation significantly enhances heat transfer performance, resulting in nearly a 300 % increase in Nusselt numbers at the base wall under conditions of heat generation. These findings offer valuable insights into the dynamic coupling of nanoparticle transport, magnetic control, and thermal regulation in unsteady MHD systems.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"113 ","pages":"Article 101617"},"PeriodicalIF":2.0,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-26DOI: 10.1016/j.dynatmoce.2025.101618
Xiaoxuan Su , Yihe Fang , Ling Zhu , Chenghan Liu , Zhenghua Tan
Based on daily precipitation data from 87 national rain gauge stations in Northeast China from 1981 to 2023 and the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data, This study reveals the characteristics of low-frequency activities of Northeast China cold vortex (NCCV) during the warm season and their impact on precipitation in Northeast China. The results show that the low-frequency activities of NCCV are closely related to the intraseasonal oscillation of middle-high latitudes. When the low-frequency NCCV activities reach the strongest, the geopotential height field over Northeast China exhibits negative anomalies, and the high-latitudes of the Eurasian continent show an anomaly pattern of “− + −”. When the NCCV key area is controlled by high-pressure anomalies, the middle-high latitudes are dominated by the East Asian-Pacific pattern from May to June. From July to September, the East Asian-Pacific pattern is weak and the Eurasian pattern is dominant. During the active phase of NCCV, Northeast China is under the control of a strong westerly jet, which is conducive to upper-level divergence. This further promotes the maintenance and development of cold vortices. At this time, the NCCV is located between two jets, which benefits energy accumulation and moisture transport. Moreover, there is obvious ascending motion over Northeast China, providing favorable dynamic conditions for notable low-frequency precipitation. The upper level low-frequency vorticity can also reflect the propagation of low frequency oscillations in the NCCV key area, as well as its upstream and downstream regions. When the NCCV is the strongest, the rear of the key area is controlled by positive vorticity anomalies, while the front is controlled by negative vorticity anomalies. The phases of NCCV low-frequency activities have good indications for cold vortex precipitation in early summer and midsummer in Northeast China. From phases 1–4, the low-frequency precipitation in Northeast China is less. As the low-frequency NCCV forms, develops and moves eastward (phases 5–8), the low-frequency rain band generates in the Liaoning Province and gradually moves northeastward, affecting Jilin and Heilongjiang provinces. As the low-frequency NCCV weakens and moves out, the precipitation in Northeast China gradually decreases from southwest to northeast.
{"title":"Characteristics of low-frequency activities of Northeast China cold vortices and their impacts on the precipitation in Northeast China","authors":"Xiaoxuan Su , Yihe Fang , Ling Zhu , Chenghan Liu , Zhenghua Tan","doi":"10.1016/j.dynatmoce.2025.101618","DOIUrl":"10.1016/j.dynatmoce.2025.101618","url":null,"abstract":"<div><div>Based on daily precipitation data from 87 national rain gauge stations in Northeast China from 1981 to 2023 and the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data, This study reveals the characteristics of low-frequency activities of Northeast China cold vortex (NCCV) during the warm season and their impact on precipitation in Northeast China. The results show that the low-frequency activities of NCCV are closely related to the intraseasonal oscillation of middle-high latitudes. When the low-frequency NCCV activities reach the strongest, the geopotential height field over Northeast China exhibits negative anomalies, and the high-latitudes of the Eurasian continent show an anomaly pattern of “− + −”. When the NCCV key area is controlled by high-pressure anomalies, the middle-high latitudes are dominated by the East Asian-Pacific pattern from May to June. From July to September, the East Asian-Pacific pattern is weak and the Eurasian pattern is dominant. During the active phase of NCCV, Northeast China is under the control of a strong westerly jet, which is conducive to upper-level divergence. This further promotes the maintenance and development of cold vortices. At this time, the NCCV is located between two jets, which benefits energy accumulation and moisture transport. Moreover, there is obvious ascending motion over Northeast China, providing favorable dynamic conditions for notable low-frequency precipitation. The upper level low-frequency vorticity can also reflect the propagation of low frequency oscillations in the NCCV key area, as well as its upstream and downstream regions. When the NCCV is the strongest, the rear of the key area is controlled by positive vorticity anomalies, while the front is controlled by negative vorticity anomalies. The phases of NCCV low-frequency activities have good indications for cold vortex precipitation in early summer and midsummer in Northeast China. From phases 1–4, the low-frequency precipitation in Northeast China is less. As the low-frequency NCCV forms, develops and moves eastward (phases 5–8), the low-frequency rain band generates in the Liaoning Province and gradually moves northeastward, affecting Jilin and Heilongjiang provinces. As the low-frequency NCCV weakens and moves out, the precipitation in Northeast China gradually decreases from southwest to northeast.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"113 ","pages":"Article 101618"},"PeriodicalIF":2.0,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1016/j.dynatmoce.2025.101615
T. Venu , MD. Shamshuddin , S.O. Salawu , Subhajit Panda
The research intends to characterize the thermal performance in micropolar fluid flows on a vertically elongated porous sheet with buoyancy-induced forces. The model incorporates the distribution of a non-uniform heat source/sink, Darcy dissipation, and the fluid flows across a porous substrate. The mathematical problem is non-dimensionalized under the similarity transformation approach as a coupled set of ordinary differential equations from the principal partial differential equations. A similarity transformation is done on the model to reduce it to ordinary differential equations are subsequently solved by the Runge-Kutta 4th order method utilizing the shooting scheme to evaluate numerical findings of dependent quantities of physical importance through MATLAB. The impact of varied parameters on the fluid momentum, angular momentum, and energy was analyzed and shown graphically. The key results revealed that the Darcy porosity meaningfully affects the momentum and thermal boundary layer. This brings about a higher wall shear stress. Micropolar fluid term contributes significantly to the microrotation and shear stress distributions development. Boundary convective conditions spur a nonlinear thermal distribution response that is sensitive to the Biot number variation for an effective boundary thermal exchange.
{"title":"Non-Darcy and Joule heating in MHD convective micropolar heat transfer flow over a stretchy cooling sheet with variable heat gain","authors":"T. Venu , MD. Shamshuddin , S.O. Salawu , Subhajit Panda","doi":"10.1016/j.dynatmoce.2025.101615","DOIUrl":"10.1016/j.dynatmoce.2025.101615","url":null,"abstract":"<div><div>The research intends to characterize the thermal performance in micropolar fluid flows on a vertically elongated porous sheet with buoyancy-induced forces. The model incorporates the distribution of a non-uniform heat source/sink, Darcy dissipation, and the fluid flows across a porous substrate. The mathematical problem is non-dimensionalized under the similarity transformation approach as a coupled set of ordinary differential equations from the principal partial differential equations. A similarity transformation is done on the model to reduce it to ordinary differential equations are subsequently solved by the Runge-Kutta 4th order method utilizing the shooting scheme to evaluate numerical findings of dependent quantities of physical importance through MATLAB. The impact of varied parameters on the fluid momentum, angular momentum, and energy was analyzed and shown graphically. The key results revealed that the Darcy porosity meaningfully affects the momentum and thermal boundary layer. This brings about a higher wall shear stress. Micropolar fluid term contributes significantly to the microrotation and shear stress distributions development. Boundary convective conditions spur a nonlinear thermal distribution response that is sensitive to the Biot number variation for an effective boundary thermal exchange.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101615"},"PeriodicalIF":2.0,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.dynatmoce.2025.101612
Noreen Sher Akbar , Salman Akhtar , Shakil Shaiq , Muhammad Fiaz Hussain , Taseer Muhammad , M. Farooq , M. Bilal Habib
The advanced energy regulation systems demand an optimal heat balance that can be successfully accomplished through the application of hybrid nanofluids. This research work examines the numerical analysis on convective heat transfer with flow attributes of hybrid nanoparticles formed from molybdenum disulfide and graphene oxide inside a circular domain having narrow edge fins. We have integrated a novel fin configuration with convective heat transfer analysis of hybrid nanofluids. Thermal convection and magnetohydrodynamic effects are employed for this steady, incompressible, laminar flow phenomenon. The complex configuration of governing partial differential equations is numerically solved by utilizing finite element simulations. The impact of fin count on thermal efficiency is evaluated by incorporating 4 and 10 fins respectively. Streamlines, isotherms, and Nusselt number patterns are analyzed against significant dimensionless parameters. The increased fin count optimizes the heat transfer mechanism through improved fluid mixing and greater recirculation zones. The synergistic effects of hybrid nanofluid flow phenomenon efficiently improves heat absorption, flow characteristics, and overall thermal efficiency. The flow field is further stabilized through the application of external magnetic field effects that promotes a uniform distribution with efficient heat transfer. The fin count and design have pivotal role in supervising flow obstructions with better heat flux in magnetohydrodynamic flow environment. The increasing value of Reynold number from 1.1 to 1.5 results in a 20 % increase of Nusselt number from 3.0 to 3.6. A further increase of 11 % in Nusselt number is noted for Reynold equal to 1.7. Nusselt number significantly increases up to 67 %, 89 %, and 95 % with an 80 % increase in Prandtl number for Reynold equal to 1.1, 1.5, and 1.7 respectively. Thus, the higher flow rate and increased viscous effects significantly enhance convective heat transfer in finned tube cavity. The studied parameters have the following ranges
{"title":"Mixed convective heat transfer enhancement in hybrid nanofluid flow through complex-finned tube cavities","authors":"Noreen Sher Akbar , Salman Akhtar , Shakil Shaiq , Muhammad Fiaz Hussain , Taseer Muhammad , M. Farooq , M. Bilal Habib","doi":"10.1016/j.dynatmoce.2025.101612","DOIUrl":"10.1016/j.dynatmoce.2025.101612","url":null,"abstract":"<div><div>The advanced energy regulation systems demand an optimal heat balance that can be successfully accomplished through the application of hybrid nanofluids. This research work examines the numerical analysis on convective heat transfer with flow attributes of hybrid nanoparticles formed from molybdenum disulfide and graphene oxide inside a circular domain having narrow edge fins. We have integrated a novel fin configuration with convective heat transfer analysis of hybrid nanofluids. Thermal convection and magnetohydrodynamic effects are employed for this steady, incompressible, laminar flow phenomenon. The complex configuration of governing partial differential equations is numerically solved by utilizing finite element simulations. The impact of fin count on thermal efficiency is evaluated by incorporating 4 and 10 fins respectively. Streamlines, isotherms, and Nusselt number patterns are analyzed against significant dimensionless parameters. The increased fin count optimizes the heat transfer mechanism through improved fluid mixing and greater recirculation zones. The synergistic effects of hybrid nanofluid flow phenomenon efficiently improves heat absorption, flow characteristics, and overall thermal efficiency. The flow field is further stabilized through the application of external magnetic field effects that promotes a uniform distribution with efficient heat transfer. The fin count and design have pivotal role in supervising flow obstructions with better heat flux in magnetohydrodynamic flow environment. The increasing value of Reynold number from 1.1 to 1.5 results in a 20 % increase of Nusselt number from 3.0 to 3.6. A further increase of 11 % in Nusselt number is noted for Reynold equal to 1.7. Nusselt number significantly increases up to 67 %, 89 %, and 95 % with an 80 % increase in Prandtl number for Reynold equal to 1.1, 1.5, and 1.7 respectively. Thus, the higher flow rate and increased viscous effects significantly enhance convective heat transfer in finned tube cavity. The studied parameters have the following ranges <span><math><mrow><mn>0.1</mn><mo>≤</mo><msub><mrow><mi>P</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>≤</mo><mn>20.1</mn><mi>;</mi><mn>1</mn><mo>≤</mo><mi>M</mi><mo>≤</mo><mn>41</mn><mi>;</mi><mn>0.1</mn><mo>≤</mo><msub><mrow><mi>G</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>≤</mo><mn>0.002</mn><mi>;</mi><mn>1</mn><mo>≤</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>e</mi></mrow></msub><mo>≤</mo><mn>31</mn><mi>;</mi><mn>1</mn><mo>≤</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>≤</mo><mn>61</mn><mi>;</mi><mn>1</mn><mo>≤</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>≤</mo><mn>6</mn><mi>;</mi><mn>0.01</mn><mo>≤</mo><msub><mrow><mi>ϕ</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>≤</mo><mn>0.05</mn><mo>.</mo></mrow></math></span></div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101612"},"PeriodicalIF":2.0,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.dynatmoce.2025.101614
T. Salahuddin , A. Maqsood , Muhammad Awais , Mair Khan , Anum Tanveer , Samia Elattar
In this study, we analyse the boundary layer flow and heat transport of a two-dimensional Cross fluid model flowing over a linearly stretched sheet. The variable thermal conductivity, mass diffusivity, chemical interactions, and viscous dissipation are also used to depict intricate transport processes. To simulate realistic stratified boundary layers, double stratification is included in both the temperature and concentration fields. By using the boundary layer approximation approach, the governing partial differential equations are obtained. The transformed ordinary differential equations are calculated by using the suitable transformations. The modelled problem is graphically handled using numerical techniques (BVP4c) in MATLAB software. Graphical representations of important factors on concentration, velocity and temperature fields are illustrated. The findings show that when the thermal stratification parameter is increased, then the wall temperature declines. For the same range of variance, solutal stratification also reduces surface concentration. The power law index and Weissenberg number reduce the velocity of fluid. The Eckert number, which measures viscous dissipation, greatly increases fluid heating and thickens the thermal boundary layer. The higher inputs of chemical reaction lower the concentration region. The variable thermal conductivity enhances the temperature region, and variable mass diffusion augments the concentration profile. The arrangement of the boundary layer is significantly influenced by the combined impacts of stratification, dissipation, and varied transport characteristics.
{"title":"Double-layer stratification of Cross fluid flow with viscous dissipation and variable thermal conductivity","authors":"T. Salahuddin , A. Maqsood , Muhammad Awais , Mair Khan , Anum Tanveer , Samia Elattar","doi":"10.1016/j.dynatmoce.2025.101614","DOIUrl":"10.1016/j.dynatmoce.2025.101614","url":null,"abstract":"<div><div>In this study, we analyse the boundary layer flow and heat transport of a two-dimensional Cross fluid model flowing over a linearly stretched sheet. The variable thermal conductivity, mass diffusivity, chemical interactions, and viscous dissipation are also used to depict intricate transport processes. To simulate realistic stratified boundary layers, double stratification is included in both the temperature and concentration fields. By using the boundary layer approximation approach, the governing partial differential equations are obtained. The transformed ordinary differential equations are calculated by using the suitable transformations. The modelled problem is graphically handled using numerical techniques (BVP4c) in MATLAB software. Graphical representations of important factors on concentration, velocity and temperature fields are illustrated. The findings show that when the thermal stratification parameter is increased, then the wall temperature declines. For the same range of variance, solutal stratification also reduces surface concentration. The power law index and Weissenberg number reduce the velocity of fluid. The Eckert number, which measures viscous dissipation, greatly increases fluid heating and thickens the thermal boundary layer. The higher inputs of chemical reaction lower the concentration region. The variable thermal conductivity enhances the temperature region, and variable mass diffusion augments the concentration profile. The arrangement of the boundary layer is significantly influenced by the combined impacts of stratification, dissipation, and varied transport characteristics.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101614"},"PeriodicalIF":2.0,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145571252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.dynatmoce.2025.101613
T. Salahuddin , Aqib Ali , Muhammad Awais , Mair Khan , Nissren Tamam , Nidhal Ben Khedher
A study is devoted to investigative a flow of Carreau Yasuda fluid flowing on the stretching cylindrical coordinate system along with variable temperature dependent thermal conductivity and concentration dependent thermal diffusivity. An Arrhenius-type reaction rate with activation energy is used to include the chemical process. The enthalpy change and double stratification are used to investigate thermal and solutal behaviors. Using the similarity transformation, the boundary layer governing equations and their related boundary conditions are converted into ordinary differential equations. The recognized numerical technique namely BVP4C method is used for the solutions of the mass concentration, boundary layer momentum and heat equations. Graphs shows the results of a study into the effect of different physical parameters. The results of current work leaves a remarkable impact in various industrial and engineering appliance. The improvement in power law index results decrease in the velocity of the fluid. The increment in the inputs of curvature parameter upsurges the velocity profile while the Weissenberg number and power law index marks the declining impression. The thermal field shows the incrementing behavior due to rising the Damkohler number, heat generation parameter, curvature parameter and thermal conduction coefficient while the decrement in the thermal response is observed due to thermal stratification parameter. The concentration profile declines due to solutal stratification parameter, Damkohler number, and activation energy coefficient, whereas increment is observed in field due to augmentation curvature parameter.
{"title":"Double layer stratifications of Carreau Yasuda fluid flow in cylindrical system along with activation energy","authors":"T. Salahuddin , Aqib Ali , Muhammad Awais , Mair Khan , Nissren Tamam , Nidhal Ben Khedher","doi":"10.1016/j.dynatmoce.2025.101613","DOIUrl":"10.1016/j.dynatmoce.2025.101613","url":null,"abstract":"<div><div>A study is devoted to investigative a flow of Carreau Yasuda fluid flowing on the stretching cylindrical coordinate system along with variable temperature dependent thermal conductivity and concentration dependent thermal diffusivity. An Arrhenius-type reaction rate with activation energy is used to include the chemical process. The enthalpy change and double stratification are used to investigate thermal and solutal behaviors. Using the similarity transformation, the boundary layer governing equations and their related boundary conditions are converted into ordinary differential equations. The recognized numerical technique namely BVP4C method is used for the solutions of the mass concentration, boundary layer momentum and heat equations. Graphs shows the results of a study into the effect of different physical parameters. The results of current work leaves a remarkable impact in various industrial and engineering appliance. The improvement in power law index <span><math><mi>n</mi></math></span> results decrease in the velocity of the fluid. The increment in the inputs of curvature parameter upsurges the velocity profile while the Weissenberg number and power law index marks the declining impression. The thermal field shows the incrementing behavior due to rising the Damkohler number, heat generation parameter, curvature parameter and thermal conduction coefficient while the decrement in the thermal response is observed due to thermal stratification parameter. The concentration profile declines due to solutal stratification parameter, Damkohler number, and activation energy coefficient, whereas increment is observed in field due to augmentation curvature parameter.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101613"},"PeriodicalIF":2.0,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145519640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-06DOI: 10.1016/j.dynatmoce.2025.101607
Mazhar Hussain , Sadia Hameed , Noreen Sher Akbar , Taseer Muhammad
<div><div>The unsteady squeezing flow of a hybrid nanofluid made up of water-suspended zinc <span><math><mrow><mo>(</mo><mi>Zn</mi><mo>)</mo></mrow></math></span> and titanium dioxide <span><math><mrow><mo>(</mo><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></mrow></math></span> nanoparticles trapped between two infinitely parallel plates is examined in this work. The need for advanced thermal management in applications where traditional fluids have poor thermal conductivity, like lubrication devices, cooling units, propulsion systems, and microelectronics, is what drives the issue. To simulate realistic operating conditions, the model incorporates radiative heat transfer, mixed convection, time-dependent magnetic field, and heat absorption. The governing partial differential equations of mass, momentum, and energy are transformed into coupled nonlinear ordinary differential equations using similarity transformations and solved numerically with MATLAB’s <strong>bvp4c</strong> solver. Results show that increasing the unsteadiness squeezing parameter accelerates the fluid motion and enhances convective heat transfer, reducing the temperature profile by up to 18 % compared with the baseline case. Suction reduces boundary layer thickness and increases heat transfer rate, while injection has the opposite effect. Stretching initially accelerates fluid motion but is eventually counteracted by viscous damping, squeezing, and Lorentz forces. Mixed convection enhances velocity by up to 12 % before destabilizing the flow at higher values. Radiation and heat absorption parameters significantly raise the temperature profile, with heat absorption increasing thermal energy near the plates by about 15 %. The novelty of this work lies in combining a time-dependent magnetic field, radiative transfer, heat absorption, and squeezing flow for the <span><math><mrow><mo>(</mo><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mi>Zn</mi><mo>/</mo><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>)</mo></mrow></math></span> hybrid nanofluid, which has not been previously addressed. These findings provide quantitative insights into optimizing hybrid nanofluid-based cooling technologies for engineering applications.</div><div>Quantitatively, the results reveal that the velocity of the <span><math><mrow><mo>(</mo><mi>Zn</mi><mi>–</mi><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><mspace></mspace><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>)</mo></mrow></math></span> hybrid nanofluid decreases by up to <strong>14 %</strong> with increasing magnetic parameter, while the unsteadiness parameter enhances velocity by nearly <strong>11 %</strong>. Heat transfer is found to increase by about <strong>17 %</strong> under suction and by nearly <strong>19 %</strong> with stronger thermal radiation, whereas heat absorption reduces the Nuss
{"title":"Computational study of thermal effects on squeezing flow of water based (TiO2−Zn) hybrid nanofluid in a parallel plates for microelectronics dispersal","authors":"Mazhar Hussain , Sadia Hameed , Noreen Sher Akbar , Taseer Muhammad","doi":"10.1016/j.dynatmoce.2025.101607","DOIUrl":"10.1016/j.dynatmoce.2025.101607","url":null,"abstract":"<div><div>The unsteady squeezing flow of a hybrid nanofluid made up of water-suspended zinc <span><math><mrow><mo>(</mo><mi>Zn</mi><mo>)</mo></mrow></math></span> and titanium dioxide <span><math><mrow><mo>(</mo><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></mrow></math></span> nanoparticles trapped between two infinitely parallel plates is examined in this work. The need for advanced thermal management in applications where traditional fluids have poor thermal conductivity, like lubrication devices, cooling units, propulsion systems, and microelectronics, is what drives the issue. To simulate realistic operating conditions, the model incorporates radiative heat transfer, mixed convection, time-dependent magnetic field, and heat absorption. The governing partial differential equations of mass, momentum, and energy are transformed into coupled nonlinear ordinary differential equations using similarity transformations and solved numerically with MATLAB’s <strong>bvp4c</strong> solver. Results show that increasing the unsteadiness squeezing parameter accelerates the fluid motion and enhances convective heat transfer, reducing the temperature profile by up to 18 % compared with the baseline case. Suction reduces boundary layer thickness and increases heat transfer rate, while injection has the opposite effect. Stretching initially accelerates fluid motion but is eventually counteracted by viscous damping, squeezing, and Lorentz forces. Mixed convection enhances velocity by up to 12 % before destabilizing the flow at higher values. Radiation and heat absorption parameters significantly raise the temperature profile, with heat absorption increasing thermal energy near the plates by about 15 %. The novelty of this work lies in combining a time-dependent magnetic field, radiative transfer, heat absorption, and squeezing flow for the <span><math><mrow><mo>(</mo><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mi>Zn</mi><mo>/</mo><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>)</mo></mrow></math></span> hybrid nanofluid, which has not been previously addressed. These findings provide quantitative insights into optimizing hybrid nanofluid-based cooling technologies for engineering applications.</div><div>Quantitatively, the results reveal that the velocity of the <span><math><mrow><mo>(</mo><mi>Zn</mi><mi>–</mi><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><mspace></mspace><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>)</mo></mrow></math></span> hybrid nanofluid decreases by up to <strong>14 %</strong> with increasing magnetic parameter, while the unsteadiness parameter enhances velocity by nearly <strong>11 %</strong>. Heat transfer is found to increase by about <strong>17 %</strong> under suction and by nearly <strong>19 %</strong> with stronger thermal radiation, whereas heat absorption reduces the Nuss","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101607"},"PeriodicalIF":2.0,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145519638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.dynatmoce.2025.101602
Sadia Ayub , Nissren Tamam , Muyassar Norberdiyeva , Nidhal Ben Khedher
Peristaltic motion is central to biomedical flows and industrial processes, yet the combined effects of complex rheology, wall compliance, and thermal-magnetic forces remain poorly understood. This study explores the peristaltic transport of Ree–Eyring nanofluid in a curved channel under magnetic field, viscous dissipation, variable viscosity, and chemical reaction. Using long wavelength and low Reynolds number approximations, the nonlinear model is solved numerically through a shooting Runge–Kutta scheme. Results demonstrate that variable viscosity parameter positively impact the velocity and temperature while negatively impacting the concentration profile of nanoparticles in lower channel. The findings provide physical insights into heat and mass transfer in non-Newtonian nanofluids, with direct applications in biomedical device design, polymer processing, and energy systems.
{"title":"Numerical simulation for peristaltic activity of Ree–Eyring nanofluid in curved configuration","authors":"Sadia Ayub , Nissren Tamam , Muyassar Norberdiyeva , Nidhal Ben Khedher","doi":"10.1016/j.dynatmoce.2025.101602","DOIUrl":"10.1016/j.dynatmoce.2025.101602","url":null,"abstract":"<div><div>Peristaltic motion is central to biomedical flows and industrial processes, yet the combined effects of complex rheology, wall compliance, and thermal-magnetic forces remain poorly understood. This study explores the peristaltic transport of Ree–Eyring nanofluid in a curved channel under magnetic field, viscous dissipation, variable viscosity, and chemical reaction. Using long wavelength and low Reynolds number approximations, the nonlinear model is solved numerically through a shooting Runge–Kutta scheme. Results demonstrate that variable viscosity parameter positively impact the velocity and temperature while negatively impacting the concentration profile of nanoparticles in lower channel. The findings provide physical insights into heat and mass transfer in non-Newtonian nanofluids, with direct applications in biomedical device design, polymer processing, and energy systems.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101602"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145466123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-29DOI: 10.1016/j.dynatmoce.2025.101611
P. Sabu , S. Cxynna , N.N.S. Vishnu , Nirmala J. Nair , Jenson V. George , N. Anilkumar , Rahul Mohan
This study examines the mesoscale eddy variability in the Southern Subtropical Front (SSTF) and Subantarctic Front (SAF) regions of the Indian Sector of the Southern Ocean (ISSO), using high-resolution underway Conductivity-Temperature-Depth (uCTD) data collected during the 11th Indian Scientific Expedition to the Southern Ocean (February–March 2020). Two mesoscale eddies—one cyclonic (41–44 °S, ∼300 km) and one anticyclonic (45–46 °S, ∼100 km)—were identified and analyzed. These features appear to be recurring, with formation driven by baroclinic instability influenced by bathymetry. The anticyclonic eddy exhibited significant modification of local thermohaline structure through water mass mixing. Eddy-induced meridional heat transport was estimated to be ∼+ 0.075 PW north of 42 °S (northward) and ∼−0.075 PW south of 42°30′ S (southward). Notably, the Subtropical Surface Water (STSW) was advected from the SSTF to SAF via the cyclonic eddy’s periphery, resulting in regional modification of water mass between 42 °S and 45 °S. Enhanced primary productivity was observed along the cyclonic eddy's boundary, with chlorophyll-a concentrations reaching 0.8 mgm-³ . These findings highlight the dynamic role of mesoscale eddies in modulating frontal systems, cross-frontal exchange, and biological productivity, offering critical insights into the physical-biogeochemical coupling in the ISSO under a changing climate.
{"title":"Recurring eddies in the Southern Subtropical and Subantarctic Frontal regions of the Indian sector of the Southern Ocean during austral summer","authors":"P. Sabu , S. Cxynna , N.N.S. Vishnu , Nirmala J. Nair , Jenson V. George , N. Anilkumar , Rahul Mohan","doi":"10.1016/j.dynatmoce.2025.101611","DOIUrl":"10.1016/j.dynatmoce.2025.101611","url":null,"abstract":"<div><div>This study examines the mesoscale eddy variability in the Southern Subtropical Front (SSTF) and Subantarctic Front (SAF) regions of the Indian Sector of the Southern Ocean (ISSO), using high-resolution underway Conductivity-Temperature-Depth (uCTD) data collected during the 11th Indian Scientific Expedition to the Southern Ocean (February–March 2020). Two mesoscale eddies—one cyclonic (41–44 °S, ∼300 km) and one anticyclonic (45–46 °S, ∼100 km)—were identified and analyzed. These features appear to be recurring, with formation driven by baroclinic instability influenced by bathymetry. The anticyclonic eddy exhibited significant modification of local thermohaline structure through water mass mixing. Eddy-induced meridional heat transport was estimated to be ∼+ 0.075 PW north of 42 °S (northward) and ∼−0.075 PW south of 42°30′ S (southward). Notably, the Subtropical Surface Water (STSW) was advected from the SSTF to SAF via the cyclonic eddy’s periphery, resulting in regional modification of water mass between 42 °S and 45 °S. Enhanced primary productivity was observed along the cyclonic eddy's boundary, with chlorophyll-a concentrations reaching 0.8 mgm<sup>-</sup>³ . These findings highlight the dynamic role of mesoscale eddies in modulating frontal systems, cross-frontal exchange, and biological productivity, offering critical insights into the physical-biogeochemical coupling in the ISSO under a changing climate.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101611"},"PeriodicalIF":2.0,"publicationDate":"2025-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145519639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-26DOI: 10.1016/j.dynatmoce.2025.101609
Noreen Sher Akbar , Javaria Akram , S. Ijaz , Zaib Jahan , Taseer Muhammad , Muhammad Bilal Habib , M. Fiaz Hussain , M. Farooq
The current research observes the intricate dynamics of two-dimensional Casson hybrid nanofluid flow along a propagating wavy channel. Incorporating effects owing to the induced magnetic field, the hybrid nanofluid, thermal radiation, and mixed convection in the flow of blood containing graphene oxide and the molybdenum disulfide nanoparticles, the research also focuses on determining the efficiency of the system by focusing on the factors contributing to irreversibility of the system. The impact of the induced magnetic field is incorporated through Maxwell equations, and the Casson model is adopted to depict the rheology of the blood. The no-slip conditions for velocity and temperature are observed along boundary walls. The dimensionless mathematical model is linearized under the lubrication approximation. The final set of ordinary differential equations is then solved through a robust finite element technique in which the computational domain is discretized into thousands of nodes. The obtained linear equations are then handled through the Gaussian elimination technique in Python. The iterative process was kept repeating until a convergence criterion of is achieved. The analysis of fluid flow properties for various parameters is performed through graphical results. Temperature is found to be raised by the thermal radiation parameter. Fluid flow is accelerated via a larger Casson parameter and magnetic Reynolds number. This model has a direct application in high-tech dynamism and heat management structures, such as biomedical devices and dense electronic cooling campaigns.
{"title":"High accuracy computational approach to study Casson hybrid nanofluid flow under induced magnetic field inside wavy walls configuration having peristaltic motion with entropy generation","authors":"Noreen Sher Akbar , Javaria Akram , S. Ijaz , Zaib Jahan , Taseer Muhammad , Muhammad Bilal Habib , M. Fiaz Hussain , M. Farooq","doi":"10.1016/j.dynatmoce.2025.101609","DOIUrl":"10.1016/j.dynatmoce.2025.101609","url":null,"abstract":"<div><div>The current research observes the intricate dynamics of two-dimensional Casson hybrid nanofluid flow along a propagating wavy channel. Incorporating effects owing to the induced magnetic field, the hybrid nanofluid, thermal radiation, and mixed convection in the flow of blood containing graphene oxide and the molybdenum disulfide nanoparticles, the research also focuses on determining the efficiency of the system by focusing on the factors contributing to irreversibility of the system. The impact of the induced magnetic field is incorporated through Maxwell equations, and the Casson model is adopted to depict the rheology of the blood. The no-slip conditions for velocity and temperature are observed along boundary walls. The dimensionless mathematical model is linearized under the lubrication approximation. The final set of ordinary differential equations is then solved through a robust finite element technique in which the computational domain is discretized into thousands of nodes. The obtained linear equations are then handled through the Gaussian elimination technique in Python. The iterative process was kept repeating until a convergence criterion of <span><math><mrow><mn>1</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup></mrow></math></span> is achieved. The analysis of fluid flow properties for various parameters is performed through graphical results. Temperature is found to be raised by the thermal radiation parameter. Fluid flow is accelerated via a larger Casson parameter and magnetic Reynolds number. This model has a direct application in high-tech dynamism and heat management structures, such as biomedical devices and dense electronic cooling campaigns.</div></div>","PeriodicalId":50563,"journal":{"name":"Dynamics of Atmospheres and Oceans","volume":"112 ","pages":"Article 101609"},"PeriodicalIF":2.0,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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