Micropolar Fluid Dynamics and Magnetohydrodynamic Applications

Micropolar fluid dynamics extends classical continuum theory by incorporating microstructure and intrinsic angular momentum into the governing equations. Unlike Newtonian fluids, micropolar fluids possess local spin fields and couple stresses arising from suspended microelements, such as rigid particles or molecular clusters. The resulting asymmetric stress tensor and additional microrotation viscosity terms enable a more accurate description of complex fluids ranging from blood and liquid crystals to engineered colloidal suspensions. When such fluids are electrically conducting and subjected to external magnetic fields, magnetohydrodynamic effects introduce Lorentz forces that interact with both translational and rotational motion. This coupling modifies velocity profiles, boundary‐layer thicknesses and energy dissipation mechanisms. Analytical solutions for idealised flows (for example, planar Couette or Poiseuille configurations) reveal the influence of key dimensionless groups—such as the Hartmann number and microrotation viscosity ratio—on flow stability, pressure drop and shear stress. Numerical approaches, including finite‐element and finite‐volume simulations with tailored user‐defined functions, have further elucidated the interplay between microstructure and electromagnetic forces in curved channels, wavy geometries and microfluidic conduits. The hybrid micropolar–MHD framework underpins advances in biomedical engineering (magnetic drug targeting, haemodynamics), cooling systems for electronic devices, magnetic seals and energy conversion technologies, offering enhanced control over flow resistance, heat transfer and rotational mixing at micro‐ to mesoscales.

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Micropolar Fluid Dynamics and Magnetohydrodynamic Applications publication trend

The graph below shows the total number of articles in micropolar fluid dynamics and magnetohydrodynamic applications across all publications each year (not limited to Nature Index journals).

Technical terms

Micropolar fluid: A continuum model for fluids with microstructure and independent spin fields, featuring asymmetric stresses and couple stresses.

Microrotation: The local angular velocity of microelements within a fluid, distinct from bulk vorticity.

Hartmann number: A dimensionless parameter measuring the ratio of electromagnetic to viscous forces in a conductive fluid under a magnetic field.

Magnetohydrodynamics: The study of electrically conducting fluid flow under the influence of magnetic fields, governed by coupled Navier–Stokes and Maxwell’s equations.

Micromagnetorotation: The rotational effect of magnetisation within micropolar fluids, representing energy exchange between magnetic and spin fields.

References

1. Computational study of micromagnetorotation on the micropolar flow characteristics in a rectangular channel with continuous applied shear. Journal of Taibah University for Science (2024).
2. Magnetohydrodynamic flow through a wavy curved channel. AIP Advances (2020).
3. Computational analysis of conductive fluid flow with tangential components of magnetic flux density and electric field in metallic and non-metallic circular pipe. Cogent Engineering (2023).
4. Implementation of micropolar fluids model and hydrodynamic behavior analysis using user-defined function in FLUENT. Advances in Mechanical Engineering (2014).