(399f) Laminar Chaotic Mixing in 3D Systems - A Thirty-Year Conversation with Robert Brodkey

When I became friends with Bob Brodkey, I was an assistant professor who had just finished a PhD on chaos in 2D systems. He, on the other hand, was one of the world's top experts on turbulent mixing. Over the next 30 years, we shared hundreds of long conversations on many topics, both personal and technical. On the personal side, he quickly convinced me to work on applied research - which I have enjoyed throughout my career. On the technical side, on the specific issue of mixing in laminar stirred tanks, he helped me realize that the traditional stirred tank with a concentric impeller has laminar flow patterns that are very close to a 2D system with a rotational symmetry. The key to enhancing mixing under such conditions was to break such symmetries, which we did by varying both temporal and spatial flow patterns. Results were dramatic - and I quickly applied the same ideas to many other systems, including impinging jets, roller bottles, and static mixers.

In this talk, I will review these case studies, and will share many memories of those 30 years of friendship.