Title: Simulation of mixed convection in a modified T-shaped enclosure with an insulated vertical strip

Authors: Hamza Khan; Humayoun Shahid; Yasir Nadeem Anjam; Salman Arif Cheema; Fayyaz Ahmed

Addresses: Department of Applied Sciences, National Textile University, Faisalabad 38000, Pakistan ' Department of Applied Sciences, National Textile University, Faisalabad 38000, Pakistan ' Department of Applied Sciences, National Textile University, Faisalabad 38000, Pakistan ' Department of Applied Sciences, National Textile University, Faisalabad 38000, Pakistan ' Department of Applied Sciences, National Textile University, Faisalabad 38000, Pakistan

Abstract: This study explores the influence of a centrally located insulated strip in a reverse T-shaped enclosure on fluid flow and heat transfer using the multi-relaxation-time lattice Boltzmann method (MRT-LBM). The bottom wall is uniformly heated and driven by a moving lid at velocity u = u₀, while the remaining walls are cold, except for adiabatic bottom shoulder segments with ϑT/ϑy = 0. The vertical insulated strip allows flow near the top wall, acting as a passive thermal barrier. Simulations are conducted for Grashof numbers from 10⁴-10⁶, Richardson numbers from 0.01-100, and Prandtl numbers from 0.7-7. The geometric influence is examined by varying L₁/L and L₂/L. Results include streamlines, isotherms, and local Nusselt number profiles, revealing that the strip significantly modifies convective structures and enhances heat transfer behaviour.

Keywords: heat transfer; mixed-convection; lattice-Boltzmann-method; reverse T-shaped enclosure; multi-relaxation-time lattice.

DOI: 10.1504/PCFD.2026.156027

Progress in Computational Fluid Dynamics, An International Journal, 2026 Vol.26 No.5, pp.315 - 331

Received: 10 Jun 2025
Accepted: 15 Oct 2025
Published online: 01 Sep 2026 *

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