Research Article
Local Thermal Nonequilibrium and Anisotropy Effects on Convective Instability of Maxwell Fluid
Nagappa Enagi*
,
Sridhar Kulkarni
Issue:
Volume 12, Issue 2, April 2026
Pages:
37-45
Received:
3 April 2026
Accepted:
20 April 2026
Published:
16 May 2026
Abstract: Thermal convection in fluid-saturated porous media has attracted considerable attention due to its wide-ranging applications in engineering and geophysical systems, such as geothermal energy extraction, underground contaminant transport, nuclear waste disposal, and heat exchangers. In these systems, buoyancy-driven flow arises when a temperature gradient is imposed across the medium. The onset of convection is primarily governed by the Rayleigh number, which quantifies the balance between thermal driving forces and dissipative effects, including viscosity and thermal diffusion. Conventional studies often assume local thermal equilibrium (LTE) between the solid matrix and the saturating fluid. However, this assumption becomes inadequate in many practical situations where the heat exchange between the two phases is not instantaneous. To overcome this limitation, the concept of local thermal non-equilibrium (LTNE) has been introduced, wherein separate energy equations are employed for the solid and fluid phases, allowing a more realistic representation of interphase heat transfer. Moreover, porous media encountered in practical applications are frequently anisotropic, with permeability and thermal conductivity varying with direction. Such anisotropy significantly influences both fluid flow and heat transport characteristics. The complexity of the problem is further enhanced when non-Newtonian fluids, particularly Maxwell fluids, are considered. Due to their viscoelastic nature, these fluids introduce additional parameters, such as stress relaxation time, which play a crucial role in determining the stability behavior of the system. Therefore, a comprehensive analysis that simultaneously incorporates LTNE effects, anisotropy, and non-Newtonian fluid behavior is essential for accurately predicting the onset of convection and gaining deeper insight into the associated stability mechanisms in porous media systems.
Abstract: Thermal convection in fluid-saturated porous media has attracted considerable attention due to its wide-ranging applications in engineering and geophysical systems, such as geothermal energy extraction, underground contaminant transport, nuclear waste disposal, and heat exchangers. In these systems, buoyancy-driven flow arises when a temperature gr...
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Research Article
Enhancing Students’ Graphing and Data Analysis Skills in Physics Laboratory Courses Through Guided Practice
Berhanu Girmay Abay*
Issue:
Volume 12, Issue 2, April 2026
Pages:
46-56
Received:
15 December 2025
Accepted:
13 January 2026
Published:
28 May 2026
DOI:
10.11648/j.ijtam.20261202.12
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Abstract: Graphing and data analysis are essential skills in physics laboratories, yet many first-year students face challenges in accurately representing and interpreting experimental data. This study aimed to investigate the effectiveness of a guided practice intervention in improving these skills among 23 undergraduate physics students at Raya University. A classroom-based action research design with a quasi-experimental pre-test/post-test approach was implemented over four weeks, embedding scaffold, step-by-step guidance into regular laboratory sessions. Quantitative data from assessments and qualitative data from student reflections, surveys, and observations were collected to evaluate the intervention. Pre-intervention assessment revealed notable weaknesses in graph construction, use of computational tools, and data interpretation. Following the guided practice, students’ average scores improved from 10 to 18 out of 20, with the largest gains observed in graphing, MATLAB application, and result analysis. Post-assessment of the experiment “Measuring Local Acceleration Due to Gravity” yielded an average value of 8.72 m/s², within 11.11% of the standard, demonstrating the accuracy and effectiveness of the intervention. Qualitative findings indicated increased confidence, improved conceptual understanding, and enhanced scientific reasoning. These results suggest that scaffold guided practice significantly enhances procedural and conceptual competencies in experimental physics. The study provides a replicable instructional model for strengthening STEM laboratory learning, particularly for students who require additional support in foundational physics skills.
Abstract: Graphing and data analysis are essential skills in physics laboratories, yet many first-year students face challenges in accurately representing and interpreting experimental data. This study aimed to investigate the effectiveness of a guided practice intervention in improving these skills among 23 undergraduate physics students at Raya University....
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