Accession Number:

ADA091235

Title:

Optimal Bodies for Minimum Total Drag at Supersonic Speeds

Descriptive Note:

Final rept.

Corporate Author:

NAVAL SURFACE WEAPONS CENTER DAHLGREN VA

Personal Author(s):

Report Date:

1980-05-01

Pagination or Media Count:

56.0

Abstract:

Two new methods were developed for predicting projectile shape which yield minimum total drag at supersonic speeds. The first technique is an Eulerian scheme that uses modified Newtonian theory and Prandtl-Meyer expansion for pressure drag with Van Driest skin friction and semi-empirical base drag prediction. The second scheme iterates body coordinates with the second-order shock-expansion theory and the same skin friction and base drag methods to minimize the total drag. A different shape is determined for each length-to- diameter ratio and Mach number. The first technique was found to calculate a reasonably accurate optimal shape, but did not predict accurate drag coefficients. It was found that the modified Newtonian theory plus Prandtl-Meyer expansion predicted pressure drag coefficients much too low whereas the second- order shock-expansion method gave good results. The second technique predicted both accurate optimal shapes and drag coefficients. Optimal shapes were predicted using the second techniques for Mach numbers 2-5 and length-to- diameter ratios of 4, 5, and 6. They were found to compare well with experimental data. Author

Subject Categories:

  • Numerical Mathematics
  • Ammunition and Explosives
  • Armor
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE