Publisher : The Korean Society of Mechanical Engineers
DOI : 10.22634/KSME-B.2001.25.9.1227
Title & Authors
Evaluation of Suboptimal Control in Turbulent Channel Flow Seong, Hyeong-Jin; Choe, Jeong-Il;
A systematic analysis is made of suboptimal control for drag reduction. The influence of the amplitude of actuation (A) and the time scale of actuation (t(sub)a(sup)+) is evaluated. Two wall sensing variables are employed (∂w/∂y│(sub)w and ∂p/∂z│(sub)w) with two wall actuations (and ). To test the suboptimal control, direct numerical simulations of turbulent channel flow at Re(sub)=100 are performed in a spectral domain. It is found that the effect of A and t(sub)a(sup)+∼1. The near-wall behaviors of flow structure are analyzed to characterize the drag reduction. The size effect of the sensor/actuator is examined.