Computational Simulation of a Plane Channel with Spalart-Allmaras Turbulence Model and Fourier Pseudo-Spectral Method

Resumo

The majority of fluid flows encountered in nature and practical applications are turbulent, characterized primarily by a broad range of scales, from large structures influenced by flow geometry to small structures determined by fluid viscosity. Turbulence is a topic of significant relevance in engineering across various sectors. For instance, airflow over terrestrial surfaces, where roughness varies considerably, is critical for predicting the potential and sizing of wind turbines and wind farms.
In this context, this study proposes extending the IMERSPEC methodology to conduct simulations of turbulent flows based on Reynolds-averaged Navier-Stokes equations, utilizing the Spalart-Allmaras turbulence model. The IMERSPEC methodology integrates the Fourier Pseudo-Spectral Method with the Immersed Boundary Method, offering excellent numerical accuracy and computational efficiency compared to other high-order techniques, attributed to the efficient use of Fast Fourier Transform (FFT) and the pressure term projection method in Fourier space.
The numerical results obtained through this approach are validated against experimental data and Direct Numerical Simulations (DNS) for flow in a flat channel at a Reynolds number of 40,000. This comparative analysis will facilitate assessing the effectiveness and precision of the proposed method in capturing turbulent flow characteristics, with potential applications in aerodynamic and fluid dynamic engineering studies.