Accession Number : ADA260890


Title :   Experimental Study of the Effect of Helical Grooves on an Infinite Cylinder


Descriptive Note : Master's thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA


Personal Author(s) : Stuart, Thomas D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a260890.pdf


Report Date : Dec 1992


Pagination or Media Count : 125


Abstract : A series of low-speed wind-tunnel investigations were conducted to determine the aerodynamic behavior of a grooved inclined cylinder representing a long trailing wire antenna towed from an orbiting airplane. The large angle-of- attack range of the trailing wire required two different model configurations. The first configuration, using full-scale wire lengths suspended between steel stanchions, was mounted on a flush four-degree-of-freedom wall balance. The second configuration used a 15-scale grooved cylinder model with an ogive nose mounted on a six-degree-of-freedom sting balance. Wall balance wire data, valid for higher angles of attack, were integrated with low angle-of-attack sting balance data. Empirical relationships for the normal and axial force coefficients were verified with historical references for tested clean circular cylinders and extended for the grooved configurations. Existence of a side force coefficient due to circulation caused by the helical grooves was discovered, expressed analytically, and verified with flow-visualization techniques. Finally, the experimental coefficients were used to improve an existing simulation model describing the static equilibrium conditions of a cable towed by an airplane in a circular orbit. Inclusion of the side force influence in the static model proved consistent with the lateral skew angle and direction observed during flight test. Inclined wire, inclined cylinder, infinite wire, infinite cylinder, normal force, axial force, side force, drogue, circulation.


Descriptors :   *AIRCRAFT , *AERODYNAMIC STABILITY , *ANTENNAS , *TRAILING WIRE ANTENNAS , *AERODYNAMIC CHARACTERISTICS , TEST AND EVALUATION , VELOCITY , COMPUTER PROGRAMS , CABLES , ANGLE OF ATTACK , STEEL , FLIGHT , AERODYNAMICS , REYNOLDS NUMBER , WIND TUNNELS , CIRCULATION , OGIVES , AERODYNAMIC DRAG , WIND TUNNEL TESTS , BALANCE , CYLINDRICAL BODIES , CIRCULAR ORBITS , LOW ANGLES , INCLUSIONS , FLOW VISUALIZATION , THESES , WIRE , MODELS , SIMULATION , ANGLES


Subject Categories : Aerodynamics
      Computer Programming and Software
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE