This book is a collection of the best peer-reviewed papers presented at the ninth Asian joint workshop on thermophysics and fluid science organized in Utsunomiya, Japan, in November 2022. The book is a valuable addition to the conference series started in the year 2006, with contents that include the research outputs from Asian countries—India, China, Japan, and the Republic of Korea. Some of the papers are collaborative efforts by academicians from these countries. The book provides an overview of recent research in the fields of fluid and thermal engineering. The chapters in the book deal with research problems on aerodynamics, propulsion, transonic and supersonic flows, aero-acoustics, fluid dynamics, thermodynamics, combustion, heat and mass transfer, and turbomachinery. Analytical, experimental, and numerical approaches are employed in the chapters. This volume will benefit academicians, researchers, and students working on research problems in thermal and fluid sciences.