Masters Theses


"Aerodynamic characteristics of two-dimensional dual airfoil systems have been investigated in an incompressible flow field in the area where improved aerodynamic characteristics are realized, due to the flow field coupling of the two airfoils. A simple analytic model has been developed to demonstrate some of the basic coupling effects in such systems. Laplace's differential equation for the stream-function has been solved numerically to determine the potential flow about dual airfoil geometries of different gap, stagger, and decalage. Two numerical methods have been employed; a finite-difference approach in Cartesian coordinates, for which the mixed boundary conditions have been transformed to the Dirichlet type on a step-wise basis, and a vortex panel method of the first order. For the finite difference solution, two methods have been introduced to reduce the sensitivity of the solution to the inherent errors in the combination of the Cartesian coordinates and curved boundaries. The potential flow solution, obtained from the vortex panel method, has been also employed along with two momentum integral methods to assess the behavior of the boundary layers on individual airfoils. Trends have been established as to the effects of the variations in the gap, the stagger, and the decalage angle on the aerodynamic characteristics of the total system. It has been shown that proper dual airfoil placement can enhance the efficiency of the system, making it superior to its equivalent single airfoil system. It has been established that an optimum geometry can cause significant delays in the boundary layer transition over individual airfoils, causing a reduction in the drag coefficient. Also, it has been determined that dual airfoil geometries of positive stagger have moment characteristics such that their aerodynamic stability is enhanced with respect to those with negative staggers and the single airfoil systems. In all cases, comparisons have been presented between the numerical and experimental results, whenever the latter has been available"--Introduction, pages iii-iv.


Selberg, B. P.

Committee Member(s)

Koval, Leslie Robert
Pagano, Sylvester J., 1924-2006


Mechanical and Aerospace Engineering

Degree Name

M.S. in Aerospace Engineering


United States. National Aeronautics and Space Administration


These results represent part of the work performed under NASA Grant NSG-2375 administered by the Helicopter Technology Division of Ames Research Center.


University of Missouri--Rolla

Publication Date

Fall 1980

Journal article titles appearing in thesis/dissertation

  • Analytical investigation of aerodynamic characteristics of dual wing systems
  • A finite difference method for calculating the inviscid flow characteristics about multiple airfoils


x, 153 pages

Note about bibliography

Includes bibliographical references.


© 1980 Kamran Rokhsaz, All rights reserved.

Document Type

Thesis - Restricted Access

File Type




Subject Headings

Drag (Aerodynamics)
Aerofoils -- Aerodynamics
Fluid dynamics -- Mathematical models

Thesis Number

T 4687

Print OCLC #


Electronic OCLC #


Link to Catalog Record

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