Sub-boundary-layer disturbance effects on supersonic base-pressure fluctuations

Jonathan R. Janssen, J. Craig Dutton

Research output: Contribution to journalArticlepeer-review


Fluctuating base pressures were measured for an axisymmetric blunt afterbody modified with two different sub-boundary-layer disturbance tabs, a triangle-tab configuration, and a strip-tab configuration, in a Mach 2.46 flowfield. Normalized rms levels indicate that base-pressure fluctuations increase with addition of the triangle tabs and decrease with the addition of the strip tab. Power-spectral-density (PSD) estimates recorded at the two outermost radial locations for the triangle-tab configuration demonstrated that the fluctuation energy increased when compared to the no-tab case at nearly all frequencies, particularly at frequencies above 1 kHz. This suggests that the triangular tabs energize turbulent structures in the free shear layer because of the introduction of stream-wise vorticity. It was also found that a prominent peak in the PSD estimate at the outer two radial locations, found in the no-tab case, is absent for the triangle-tab configuration. Dual-transducer measurements for both tab configurations suggest that correlated pressure fluctuations are realized at most locations across the base simultaneously, lending credence to the idea that a global mechanism acts as a source of the base-pressure fluctuations.

Original languageEnglish (US)
Pages (from-to)1017-1024
Number of pages8
JournalJournal of Spacecraft and Rockets
Issue number6
StatePublished - 2005
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science

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