This book is designed for undergraduate and graduate engineering students who are encountering computational fluid dynamics for the first time in their study of fluid machines. The approach emphasizes a gradual and effective learning process, aiming to minimize the time required to attain a solid foundational understanding. Clarity of exposition is prioritized over strict mathematical rigor, with continuous reference to the physical significance of the mathematical formulas presented. This approach enables students to independently produce acceptable results for most case studies of general interest. The book provides a comprehensive collection of essential concepts needed for correctly configuring any computational fluid dynamics software. To enhance accessibility, it focuses on OpenFOAM, a free and open-source software renowned for its extensive community of developers and users.