Multivariable Closed-Loop Flow Control of Drag And Yaw Moment For A 3D Bluff Body

Abstract

A multivariable closed-loop active flow control strategy to reduce the drag coefficient and yaw moment of a 3-dimensional bluff body is presented and applied in wind tunnel experiments. The relevant flow characteristics are investigated and discussed for several crosswind angles from 0 ◦ to 10 ◦ at Reynolds numbers from 300000 to 500000. Dynamic black-box models are identified from experimental data and a robust multivariable H∞-controller is synthesized using the mixed-sensitivity loop-shaping approach. The controller’s capability to reduce the drag coefficient by more than 22 % corresponding t net power savings of about 15 % as well as its performance to suppress disturbances of the yaw moment during cross-wind gusts are demonstrated in experiments.