The main focus of the special issue is to bring out the innovative research works accomplished in the diverse fields of fluid dynamics and functional materials. Research works pertaining to fluid motion (liquid and gas) inside the containers with different profiles are invited for publication. Also, challenges are found while preparing the nanofluids and dispersion stability for long-run use. As far as the functional materials are concerned the research works related to building materials, materials for automobiles, materials for the green environment and sustainability are in great demand. Finally, the materials are required to achieve energy conservation in industries and domestic applications. Thus, this special issue invites the articles to deal with the challenges of the aforementioned subjects.