ABSTRACT ZHUANG CTS-95-20165 Michigan State University This work consists of an investigation of the scalar mixing field of mixing layers using direct numerical simulation (DNS). The effects of 2- and 3- dimensional external perturbations on the scalar mixing field of two-stream mixing layers without chemical reactions will be studied. The overall goal is to understand how to use fluid mechanics to enhance scalar mixing of mixing and layers and thereby aid in the development of more efficient reaction chambers and propulsion systems. This research is funded through the Research Planning Grants for Women Scientists and Engineers Program.