The International Organizing Committee of Asian Joint Workshop on Thermophysics and Fluid Science (AJWTF) is delighted to be publishing the papers selected at the 9th AJWTF as a special issue in the Open Journal of Fluids Dynamics (OJFD, SCIRP). The 9th AJWTF was successfully held at Utsunomiya Japan, during November 27 to 30, 2022, although it was held both in-person and virtually, amid lingering fears of COVID-19. The participants more than 250 were able to have a very good time to actively discuss and exchange recent research information at the Venue and they enjoyed the wonderful sightseeing at the world heritage Nikko, in which the participants can experience the Japanese culture and nature. The workshop provided an excellent platform to disseminate researches on thermo-fluids sciences and related engineering applications, and the participants were also able to learn some valuable lessons from many experts in their respective fields.