He was admitted an Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA) in 1995. He was elected a Fellow of the Institution of Mechanical Engineers, UK (IMECHE) in 1997. He became a Fellow of the American Society of Mechanical Engineers (ASME) in 2011. He has taught and performed research in various universities in Nigeria, Germany, Japan and USA. In addition, he has been a consultant to several companies in the power generation and aerospace industries, including Electricite de France, and NASA. He has made contributions in three broad areas of research: Complex turbulence flow computations with Reynolds stress modeling, environmental fluid mechanics through modeling of jets in cross flow, and analysis and development of numerical methods for computational fluid dynamics (CFD) applications. He has over 100 publications; many in the top journals in the field. His pioneering work on turbulence-driven secondary motion in non-circular ducts, published in the Journal of Fluid Mechanics in 1984, has been recognized worldwide; according to Google Scholar, it has received over 300 citations since publication.

He received recognition for his research on accuracy of computational methods with the 1995 Lewis Moody award of the ASME Fluids Engineering Division. Professor Demuren has developed and taught numerous courses, including, fluid mechanics, computational methods, heat transfer, and turbulence. In addition, he has graduated 18 doctoral and masters graduate students, who now hold prominent positions in academia, engineering and financial industries.