Abstract

Many road vehicles such as cars and lorries are not shaped in an aerodynamically efficient manner due to aesthetic, practical and legal constraints. Such vehicles are often classified as bluff bodies, and consequently have a large three-dimensional wake which contributes significantly to the aerodynamic drag on these vehicles. While many passive and active methods exist to reduce the drag of 3D bluff bodies, they generally involve either large geometric changes or high energy consumption. An alternative method involves the use of feedback control and small actuators to efficiently regulate key features of the wake. strategies that are experimentally implemented on a high Reynolds number bluff body wake. This first involves an assessment of the wake observability to determine which features of the wake may be robustly measured from body mounted pressure data alone. A second stage is the development of stochastic models that describe key features of the wake and provide insight for feedback control design. These feedback controllers are then implemented, demonstrating that efficient drag reduction is possible, but that the control can be challenged by fundamental limitations.

In this talk we will discuss the development of feedback control