Available at: http://digitalcommons.calpoly.edu/theses/1472
Date of Award
MS in Aerospace Engineering
The use of panel codes in the aerospace industry dates back many decades. Recent advances in computer capability have allowed them to evolve, both in speed and complexity, to provide very quick solutions to complex flow fields. By only requiring surface discretization, panel codes offer a faster alternative to volume based methods, delivering a solution in minutes, as opposed to hours or days. Despite their utility, the availability of these codes is very limited due to either cost, or rights restrictions.
This work incorporates modern software development practices, such as unit level testing and version control, into the development of an unstructured panel code, CPanel, with an object-oriented approach in C++. CPanel utilizes constant source and doublet panels to define the geometry and a vortex sheet wake representation. An octree data structure is employed to enhance the speed of geometrical queries and lay a framework for the application of a fast tree method. The challenge of accurately calculating surface velocities on an unstructured discretization is addressed with a constrained Hermite Taylor least-squares velocity formulation. Future enhancement was anticipated throughout development, leaving a strong framework from which to perform research on methods to more accurately predict the physical flow field with a tool based in potential flow theory.
Program results are verified using the analytical solution for flow around an ellipsoid, vortex lattice method solutions for simple planforms, as well an anchored panel code, CBAERO. CPanel solutions show strong agreement with these methods and programs. Additionally, aerodynamic coefficients calculated via surface integration are consistent with those calculated from a Trefftz plane analysis in CPanel. This consistency is not demonstrated in solutions from CBAERO, suggesting the CHTLS velocity formulation is more accurate than more commonly used vortex core methods.