The physics of vortex flows in stratified fluids is studied with the objective of determining the influence of stable stratification on the descent of aircraft vortex pairs. Vortex rings descending into linear and discontinuous density stratifications are investigated experimentally and simulated numerically. The computer code used for this is based on a second-order closure turbulence model of the Reynolds stress equations in axisymmetric coordinates. Verification of the code is provided by the agreement found between the measured and calculated results. The two-dimensional version of the code is then used to simulate a measured Boeing-747 vortex descending in stable stratification. The strength and tightness of the measured vortex cores have necessitated developedment of a new method of numerically calculating strong vortex flows. The comparison of measured with calculated descent velocity, descent distance, swirl velocity, and circulation in the vortex is in agreement. It is concluded that turbulence effects must be accounted for in the study of aircraft vortex behavior. It is found that unaleviated vortices remain strong during descent, that the vortices stop descending due to a diffuse region of countersign vorticity outboard and above the cores, and that core separation does not primarily control descent. (Author)

  • Corporate Authors:

    Aeronautical Research Associates of Princeton

    50 Washington Road, P.O. Box 2229
    Princeton, NJ  United States  08540

    Federal Aviation Administration

    Systems R&D Service, 800 Independence Avenue, SW
    Washington, DC  United States 

    Transportation Systems Center

    55 Broadway, Kendall Square
    Cambridge, MA  United States  02142
  • Authors:
    • Hecht, A M
    • Bilanin, A J
    • Hirsh, J E
    • Snedeker, R S
  • Publication Date: 1979-2

Media Info

  • Pagination: 130 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00197566
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: FAA-RD-79-10 Final Rpt., ARAP-372
  • Contract Numbers: DOT-TSC-1488
  • Files: NTIS, TRIS, USDOT
  • Created Date: Aug 28 2003 12:00AM