Application of the principle of breaking ocean waves to mixing technology

Abstract

Turbulent mixing in the multiphase system of breaking ocean waves and whitecaps is known to play an important role in the mass exchange between ocean and atmosphere. Thus engineering applications to this naturally occurring dynamic exchange process appear to be of interest in various areas of applied mixing technology. Starting from the fact that ocean waves break after having reached their point of instability, a three-dimensional collapsible swivel mechanism (CSM) was developed for simulating by mechanical means the highly dynamic movement of breaking ocean waves. The CSM, employing reversion kinematics of a six-link spatial kinematic chain, has been realized in the construction of a new mixing technology (called swing mixer) that can either move the fluid by the use of mixing tools in a vessel (stirrer principle) or by moving the entire vessel (shaker principle). A first description of swing mixers has recently been given.1 A special characteristic of swing mixers is their three-dimensional reversing motion, the forward and backward paths being nonsuperimposable mirror images of one another. During the mixing process in swing mixers, the efficient mixing principle of repeated stretching and folding2 also takes place in the third dimension. Details of the mixing technology of swing mixers will be discussed together with some suggestions as to how spatial and temporal changes in the concentration may be determined with the help of CCD cameras in a given multiphase system agitated by swing mixers.