Accession Number : AD0869666

Title :   A Method for Determining Drag Coefficients from Observed Position Data.

Descriptive Note : Technical rept.,

Corporate Author : NAVAL WEAPONS LAB DAHLGREN VA

Personal Author(s) : Barker, R. G. ; Frick, C. H. ; McAnelly, L. J.

Report Date : APR 1970

Pagination or Media Count : 36

Abstract : A method is presented for computing the aerodynamic drag of a body in free flight. Polynomial least squares smoothing of position data is used for the first estimate with an optional provision of improving these results by matching arc length. All values thus obtained from one or more drops are then used to obtain a single least squares fit with the drag coefficient formula of T. S. Walton and Daniel Shanks. The nonlinear portions of this fitting problem are solved with good results using a quadratic minimization routine provided the data cover a sufficient Mach number range. This method is both fast and accurate. It replaces a procedure which was more expensive in computer time and in the required efforts of experienced personnel. (Author)

Descriptors :   *DRAG), (*BOMBS, FREE FLIGHT TRAJECTORIES, LEAST SQUARES METHOD, FREE FALL MISSILES, CURVE FITTING.

Subject Categories : Aerial Bombs
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE