Welcome to the 33rd International Symposium on Transport Phenomena (ISTP-33), which will be held on September 24-27, 2023 in the Kumamoto-Jo Hall, Kumamoto city, Japan.

Transport phenomena, including the heat and mass transfer and fluid flow, can be found in the various kind of science and engineering fields. It covers from nanoscale to macroscale, from single-phase to multiphase, from non-reactive to reacting flows, and for applications from on the ground to in space. Further improvement of conventional technologies or development of breakthrough new technologies is highly demanded under the global slogan of SDGs (Sustainable Development Goals). ISTP-33 provides an opportunity for researchers, scientists, engineers, and students engaging in the studies of transport phenomena to get together and to stimulate each other. Unfortunately, the latest ISTP within these two years, ISTP-31 and ISTP-32, were conducted by a way of full virtual style (online symposium) due to COVID-19. All organizing committee members of the ISTP-33 hope to make a face-to-face event once again possible after the COVID-19 pandemic has come to an end. We are striving to organize a symposium where many participants from all over the world can both enjoy thought-provoking discussions in technical sessions, and make new friends. We are looking forward to seeing you in Kumamoto at the ISTP-33, in September 2023.