A variety of large-scale manufacturing and transport processes encounter dispersed multiphase flows, i.e., flows with dispersed bubbles or particles. These in particular include flows in chemical plants and flows in which catalytic chemical reactions occur, such as in the Fischer-Tropsch process.  All these dispersed multiphase flows are not laminar, but turbulent. The questions we want to address in this cluster are: How do bubbles affect mixing of reactants in such bubbly turbulent flows? How do bubbles change the mixing efficiency? What are the optimal parameters for the mixing of reactants?  What is the interplay between the bubbles, the catalytic particles, and turbulent fluctuations on the mixing in turbulent multiphase flows? We will use both experimental methods such as Laser Doppler Velocity and high speed imaging as well as computational fluid dynamics such as front-tracking and immersed boundary techniques to answer these questions.