Actuator Requirements for Flow Control

Due to chaotic nature, the turbulent flow is high dimensional in nature. Therefore, the implementation of turbulent flow control schemes for practical applications is challenging. However, the form and structures of turbulent flow can be diagnosed, and control of turbulent flow is realizable by suitable actuation. It is difficult to specify the requirement of an ideal actuator for turbulent flow control. The ideal characteristics of an actuator for turbulent flow control can be described based on the following guidelines  

Turbulent flow is quite sensitive to the surface roughness. The actuator should not introduce additional roughness to the surface of the device. It should not have parasitic effect on the flow when the actuator is switched off. 

The frequency to be introduced by the actuators should match with the spatial and temporal frequencies present in the turbulent flow. The high Reynolds number flow has spatial and temporal frequency of the order of microns and kilohertz, respectively. Therefore, MEMS-based actuators are ideal for turbulent flow control due to their smaller physical dimension and lower inertia. 

Strength is the other requirement of actuator for maintaining the integrity against the load from the fluid forces. 

During implementation of distributed control with multiple actuators for optimal turbulent flow control, the behavior of the actuators should be uniform for all actuators. 

---