Accession Number:

ADA180610

Title:

Boundary-Layer Stability Analysis for Sharp Cones at Zero Angle-of-Attack

Descriptive Note:

Final rept., Jun 82-Feb 1986

Corporate Author:

CALIFORNIA INST OF TECH PASADENA JET PROPULSION LAB

Personal Author(s):

Report Date:

1986-08-01

Pagination or Media Count:

52.0

Abstract:

The stability characteristics of an uncooled sharp cone at zero angle of attack have been calculated at an edge Mach number of 6.8 and a stagnation temperature of 728 K 1310 R using spatial normal modes. Transformed flat-plate boundary-layer profiles were used for the mean flow. By a consideration of both two-dimensional and oblique waves, it has been determined that instability at this Mach number is primarily a two-dimensional second-mode instability. Comparisons with available stability experiments show that the calculated unstable frequencies were present in the experiments, but the measured amplification rates differ from the calculated. A band of unstable high frequencies above the second-mode region that starts at about R1400 is not accounted for by the theory. Comparisons of amplitude-growth curves for both cones and flat plates at March numbers 4.5, 5.8 and 6.8 show that the most unstable normal modes on a cone have at least as much total growth as on a flat plate at Mach 4.5 and more total growth at the other two Mach numbers. Keywords Boundary layer stability Hypersonic linear stability theory Hypersonic cone stability.

Subject Categories:

  • Numerical Mathematics
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE