Dr. Sofen Kumar Jena is currently a researcher at the Process & Energy Laboratory in the Department of Mechanical Engineering at the Technical University of Delft, Netherlands. Dr. Jena holds a PhD in Mechanical Engineering and has over a decade of experience in research and professional work, particularly in applied mathematics. His expertise spans various domains, but his primary focus has been on turbulence modelling and the analysis of turbulence signals, which are key components of his research. This book emerges from his core research, reflecting his deep engagement with the mathematical principles behind signal analysis in turbulent systems. Dr. Jena’s unique combination of profound theoretical understanding and practical experience allows him to present intricate mathematical concepts in an accessible and engaging manner. His work consistently bridges the gap between complex theoretical constructs and their real-world applications, offering readers a comprehensive understanding and practical insights.