Turbulence accounts for most of the processes in textile engineering among other interdisciplinary fields. In this chapter, a comprehensive description of turbulent models and description of important terms and theories in modeling and simulation have been exhaustively presented. Analysis of turbulent forces, model equations, description of types of turbulence models, the turbulence phenomena, and application of this concept in modeling and simulation are some of the information presented in this chapter. This chapter extensively explains the foundation of computational fluid dynamics (CFD) with practical examples of typical problems, solution strategy, implementation, and validation of algorithm. This chapter also demonstrates the applicat...