Turbulence Chapter 4: Laminar-turbulent Transition Modeling
This chapter focuses on the modeling of laminar–turbulent transition in RANS simulations. The transition region affects boundary layer behavior, drag, and heat transfer, and cannot be captured by fully turbulent models. Different transition mechanisms are introduced, followed by an overview of modern transition models based on intermittency, laminar kinetic energy, and empirical correlations. The summary includes Fluent-specific implementations and practical considerations for setup and mesh requirements.
Turbulence Chapter 3: Near-Wall Modeling
In this chapter, we journey into the turbulent zone right next to the wall — where sharp gradients, subtle balances, and small-scale chaos control the drag, heat transfer, and flow separation that engineers care about. We explore how near-wall turbulence is structured, how CFD models like wall functions or enhanced wall treatments handle it, and why roughness and mesh strategy matter more than you might expect. This is where the wall stops being just a boundary and becomes the real battleground of turbulence.
Turbulence Chapter 2: Turbulence Anisotropy in RANS
Reynolds-Stress Models (RSM) aim to capture the directional complexity of turbulence where simpler models fail. This post breaks down the theory behind RSM, explains when and why it’s needed, and offers intuitive analogies and stability tips — all framed through the Socratic questions we use throughout the course.
Turbulence Chapter 1: Review of RANS-Boussinesq Models & Statistical Turbulence Description
Turbulence modeling is at the core of modern Computational Fluid Dynamics (CFD), bridging the gap between theoretical fluid mechanics and practical engineering applications. This guide explores the fundamentals of turbulence, from the Reynolds-Averaged Navier-Stokes (RANS) approach and the Boussinesq hypothesis to improved RANS models like Realizable k-ε, RNG k-ε, and curvature-corrected models. With a focus on practical CFD applications, we delve into turbulence production limiters, near-wall treatments, and Fluent best practices. This structured study consolidates critical turbulence modeling concepts, equipping CFD engineers with the knowledge to select and implement the most suitable models for their simulations.