ABSTRACT
Recently, interest in how to control thermal and fluid phenomena has increased significantly due to an immense need for control technologies aimed at drag reduction, noise reduction, and mixing enhancement. In the case of large-scale vehicles, such as an airplane or oil tanker, the skin-friction drag is about 70 to 90% of the total drag. Therefore, reducing turbulent fluctuations to reduce skin-friction is one of the most important problems in fluid mechanics. On the other hand, a great benefit also can be obtained by increasing turbulence. For example, turbulence should be increased in order to mix air and fuel efficiently or to decrease the form drag of bluff bodies such as a golf ball.
