We are surrounded by fluids, which are continually deformable substances such as air and water. The motions of fluids are usually complicated, and it seems difficult to understand, predict, or control them. Our group, the Fluid Mechanics Group in the Graduate School of Engineering Science in Osaka University, is challenging to unveil simple and beautiful physics behind such complicated flow phenomena. Our aim is twofold. One is to develop a new science of fluid mechanics. The other is for engineering applications on the basis of scientific findings. Namely, once we understated the principle of a complicated flow phenomenon, we may effectively develop a technology not relying on trial and error. To achieve these objectives, we are studying various flow phenomena by means of the effective combinations of theoretical analyses, numerical simulations on modern supercomputers and laboratory experiments using state-of-art measurement techniques.