Research Article
Computational Analysis of Yield Stress Fluid Behavior over a Heated Surface-mounted Block with
Temperature-dependent Viscosity
Issue:
Volume 12, Issue 2, June 2026
Pages:
24-31
Received:
2 April 2026
Accepted:
17 April 2026
Published:
21 May 2026
Abstract: A numerical investigation of laminar viscoplastic flow past a heated square cylinder on a plane wall is presented using the Bingham and Casson models with Papanastasiou regularization. A two-step methodology first establishes fully developed channel flow at Re = 100, then uses it as inflow for the main problem at Re = 500. Effects of Bingham number (Bn = 0, 10, 30) on flow structure are examined. Results show progressive growth of unyielded zones (black regions) with increasing Bn, where fluid behaves as a rigid solid body. At Bn = 0, no unyielded zones exist, and symmetric streamlines with recirculation are observed. At Bn = 10, unyielded zones emerge upstream and, in the wake, suppressing vortex formation. At Bn = 30, these zones form an elongated rigid plug that eliminates recirculation. The regularized model captures yield surface evolution without numerical instability. Yield stress fundamentally governs flow morphology; unyielded regions grow and coalesce as Bn increases, reducing deformation and suppressing convective mixing with significant implications for heat transfer. Temperature-dependent viscosity is characterized by the Pearson number Pn, while the Casson number Ca represents the yield stress to viscous force ratio. This study aids design of thermal systems for heat exchangers, polymer processing, food sterilization, drilling operations, and biomedical devices.
Abstract: A numerical investigation of laminar viscoplastic flow past a heated square cylinder on a plane wall is presented using the Bingham and Casson models with Papanastasiou regularization. A two-step methodology first establishes fully developed channel flow at Re = 100, then uses it as inflow for the main problem at Re = 500. Effects of Bingham number...
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Research Article
Flow and Heat Transfer Through Vertical Channel with Radiation and Chemical Reaction in the Presence of Magnetic Field
Issue:
Volume 12, Issue 2, June 2026
Pages:
32-50
Received:
17 February 2026
Accepted:
23 March 2026
Published:
18 June 2026
DOI:
10.11648/j.ijfmts.20261202.12
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Abstract: A study has been carried out to investigate the three–dimensional free convective heat and mass transfer flow of a viscous incompressible fluid within a vertical channel. The analysis considers the combined effects of thermal radiation and a chemical reaction, which are important in many engineering and industrial processes such as energy systems, cooling devices, and chemical processing units. The presence of a magnetic field is also taken into account because it significantly influences the motion of electrically conducting fluids. The governing equations representing the conservation of momentum, energy, and concentration are formulated under appropriate physical assumptions. These equations are nonlinear and coupled in nature; therefore, they are first transformed into non–dimensional form using suitable similarity parameters. An approximate analytical solution of the resulting equations is then obtained by applying a perturbation technique. This method enables the determination of velocity, temperature, and concentration distributions inside the vertical channel and helps in analysing the influence of different physical parameters on the flow characteristics. The results reveal several important features of the flow. In the case of a cooling plate, the primary velocity component decreases with an increase in the magnetic parameter, chemical reaction parameter, Prandtl number, and Schmidt number. The magnetic field introduces a resistive force, which tends to slow down the fluid motion. Similarly, larger values of the Prandtl and Schmidt numbers reduce thermal and mass diffusivity, leading to a reduction in fluid velocity. On the other hand, the primary velocity increases with increasing values of the thermal Grashof number and mass Grashof number, since these parameters represent buoyancy forces that enhance the fluid motion within the channel. It is also observed that the temperature distribution decreases with an increase in the Reynolds number, Prandtl number, and radiation parameter. Furthermore, the concentration field decreases when the Schmidt number, Reynolds number, or chemical reaction parameter increases, indicating a reduction in species diffusion within the fluid flow.
Abstract: A study has been carried out to investigate the three–dimensional free convective heat and mass transfer flow of a viscous incompressible fluid within a vertical channel. The analysis considers the combined effects of thermal radiation and a chemical reaction, which are important in many engineering and industrial processes such as energy systems, ...
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,
Mrinmoy Guria*
