Numerical Evaluation of the IMERSPEC Methodology and Spalart-Allmaras Turbulence Model in Fully Developed Channel Flow Simulations

This study evaluates the performance of the IMERSPEC methodology combined with the Spalart-Allmaras turbulence model for simulating fully developed turbulent flows in a plane channel. Turbulent flows, known for their complexity, require numerical methods that balance computational efficiency with accuracy. The IMERSPEC approach, recognized for its spectral accuracy and efficiency, was applied alongside the Spalart-Allmaras model, valued for its simplicity and robustness in representing turbulence, particularly in scenarios where flow over solid surfaces is critical. Simulations were conducted at Reynolds numbers (Re tau) of 180, 550, and 1000, with results validated against direct numerical simulation (DNS) data. The study investigated various grid resolutions, revealing that finer meshes substantially enhance accuracy by mitigating velocity profile oscillations and reducing the L2 error norm. Key findings highlight the method's ability to accurately replicate turbulent flow characteristics, including velocity distributions and shear stress profiles, while maintaining a favorable computational cost-to-accuracy ratio. This work provides valuable insights into turbulence modeling, demonstrating the potential of the IMERSPEC methodology for practical engineering applications.