準最適制御を用いた角柱周り流れの抵抗低減

抄録

We apply the suboptimal control theory to a flow around a square cylinder to investigate its control effect. The cost function is chosen to be the pressure drag. The control input is assumed to be continuous blowing and suction on the cylinder wall. The control law is derived so as to minimize the cost function under the constraint of linearized NavierStokes equation. With this control input, the mean drag coefficient is found to reduce by 6.6% at most. Vortex shedding from the cylinder is also suppressed to result in reduction of the lift fluctuations.