Motivation

THE A. JAMES CLARK SCHOOL of ENGINEERING

Traditional main rotor hub designs contribute up to 1/3 of the total pressure drag on helicopters, decreasing efficiency. At some point along the fairing body, the boundary layer loses its energy and the flow separates, contributing drag.

Solution: Piezoelectric Synthetic Jet Actuator Arrays

Experiment

Northrop Grumman MQ-8C Fire Scout

Expected Results

Jet actuators accelerate the flow close to the airfoil surface, creating a low pressure area where the flow remains attached.

Applying electricity oscillates the piezo disk back and forth, creating a small jet of air through the orifices.

Experimental Analysis of the Effect of Interaction Parameters on Synthetic Jet Actuator Arrays (Hasnain et. al.)

Put two actuators together, and by varying the voltage to each, you can create a vectored flow over the body and re-energize the boundary layer, keeping flow attached longer.

How do we keep flow attached longer?

• Decreased pressure drag • Increased aerodynamic performance

(Flow Control Using Plasma and Synthetic Jet Actuators on

Bluff Bodies (Sarah Haack, 2007)

• Aerodynamics of a flow over a cylinder are well understood, so I chose this design for ease of comparison.

• I placed synthetic jet actuator arrays at both +70° and -70 ° to the free stream, the optimal angle for reducing pressure drag (Haack, 2007).

• Took pressure data along the surface of the cylinder

• Created flow visualization images with a laser