University of Minnesota
University of Minnesota








Doublet Lattice based Unsteady Aerodynamics Analysis
A Matlab code has been developed in the group to compute the unsteady aerodynamics of an aircraft based on a panel method. The panel method used is the Doublet Lattice Method (DLM) which gives the pressure difference across a lifting surface subjected to harmonic oscillations in a steady flow (conversely, the surface can be considered stationary, and incoming flow can be considered oscillatory). The code can be downloaded at
This code uses 3 doublets for approximating the doublet distribution across each panel via a parabolic approximation. It is capable of solving for any 3-D surface which has a thin airfoil assumption. Also, the code is capable of carrying out the Roger’s approximation which fits frequency response from the DLM to a transfer function in a least squares manner. To ensure that the results at zero oscillating frequency i.e. steady state, match the standard Vortex Lattice method (VLM), the code subtracts out the steady flow solution from the results of all unsteady computations. Then, results from a VLM code, which has also been developed from the basics, is added in. Except for the script for gridding, all the other components of the code are general and can be used for any 3-D lifting surface.
Graduate Student: Aditya Kotikalpudi