Publication Date


Document Type


Committee Members

Zifeng Yang, Ph.D. (Advisor); Jim Menart, Ph.D. (Committee Member); Junghsen Lieh, Ph.D. (Committee Member)

Degree Name

Master of Science in Aerospace Systems Engineering (MSASE)


The dual-plane airfoil has been adopted in the design of aircraft wings, wind turbine blades, and propellers. The purpose of this research is to investigate the most important design parameters of a dual-plane airfoil model for the best aerodynamic performance, such as gap, stagger, and decalage. The dual-plane airfoil model was designed using the S826 profile. A mechanical mechanism with electrical actuator control is particularly designed to alter the gap and stagger smoothly, as well as the angle of attack (AOA) for each airfoil. It results in a gap range of 1.38c to 2.17c, a stagger range of -0.75c to 1.75c (c is the chord length), an AOA range of -10 to 20 degrees. The decalage angles of 0, 1, and 2 degrees are adopted in the tests for AOA=12 degrees. A low-speed open-circuit wind tunnel at Wright State University is used for the experiment at two Reynolds numbers, ����=60000, and ����=100000, respectively. Both airfoils are equipped with 21 pressure tap holes around the airfoil in the middle section. Pressure distribution data around the airfoil is sampled at a rate of 400 Hertz using the DSA 3217 Pressure Scanner. The collected data is processed to calculate the pressure coefficient on the surface of both airfoils. The pressure distribution profiles are generated and compared at various gaps, staggers, and decalages. Lift and drag coefficients are calculated by integrating the pressure distribution over the airfoil. It has been found that both stagger and gap have a significant effect on the pressure distribution at AOA of 12 degrees for the bottom airfoil. A gap ranges from 1.38c to 1.57c can suppress the separation and increase the lift coefficient of the top airfoil at various staggers and decalages. A stagger of 1.75c and negative staggers at a gap of 1.38c can suppress the separation and increase the lift coefficient of the bottom airfoil. Due to boundary layer separation, negative staggers are not effective for ����=60000. The decalage effect is distinct at a decalage of 2°. But this effect is only observed for the top airfoil. Thus, the dual-plane airfoil model is most effective at decalages of 0° and 1°. It indicates that the relative position of the two airfoils plays a very important role in the overall aerodynamic performance of the dual-plane airfoil. The aerodynamic efficiency calculation shows that a maximum efficiency (L/D) of 20.7 is obtained at a gap of 1.38c, a stagger of 1.75c, and a decalage of 0° for ����=60000 and a maximum efficiency of 21.1 is obtained at a gap of 1.38c, a stagger of -0.50c, and a decalage of 0 for ����=100000. Pressure distribution data was also collected for a single airfoil configuration to compare the performance of the dual-plane airfoil model with the single airfoil model. It was found that the single airfoil model generated a maximum efficiency of 9 at AOA=13° degrees for ����=60000 and a maximum efficiency of 9.8 at AOA=13° degrees for ����=100000. The underlying flow physics is studied through detailed flow field quantification using particle image velocimetry (PIV). The PIV measurements on the flow over the top and bottom airfoils are obtained in correlation with the pressure measurements. The suppression of the separation due to the certain gap and stagger is revealed by the PIV measurements, which validates most of the pressure data collected during the pressure tests.

Page Count


Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded