User guide for cp2cl plusm v3.x: A program to provide forces and moments from airfoil pressure

Abstract

The code cp2cl plusm is a c code designed to read the variables x (chord direction), y (or z) (vertical direction) and CP (pressure) as input, and provide CL (lift), CD (drag) and CM (pitching moment) as output. cp2cl plusm is a verified code which is based on earlier codes by A.D. Gardner and K. Richter, and performs first-order integration of airfoil pressure distributions to forces. Pressure integration is a simple task, which is easy to perform incorrectly. Particularly in cases where the pressure distribution is resolved with too few measurement points, the results of the integration depend strongly on the integration technique used. The code can perform the following common tasks: • Integration of finely-distributed pressure distributions from CFD • Automatic reduction of finely-distributed pressure distributions from CFD to experimentally-measured pressure-tap positions and comparison with the original data • Integration of experimental pressure distributions • Handling of special cases: Pressure distributions without leading edge and trailing edge pressure sensors, scaling and translation of airfoil position, handling of geodesic (reversed) coordinate system. • Two simple sorting algorithms are implemented, which can deal with some simple cases. • A block-data mode is implemented which allows the sorting of large numbers (millions) of pressure distributions in acceptable time.