Flowfield measurements in the vortex wake of a missile at high angle of attack in turbulence

The flowfield downstream of a vertically-launched surface-to-air missile model at an angle of attack of 50° and a Reynolds number of 1.1 x 10(5) was investigated in a wind tunnel of the Naval Postgraduate School. The goal of this thesis is to experimentally validate the pressure measurement system for flowfield variables with elevated levels of turbulence; to determine the location and intensity of the asymmetric vortices in the wake of the VLSAM model at a raised level of freestream turbulence; and to display the asymmetric vortices by velocity mapping and pressure contours. The purpose is to correlate the results with the force measurements of Rabang to provide a greater understanding of the vortex flowfield. The body-only configuration was tested. Two flowfield conditions were treated: the nominal ambient wind tunnel condition, and a condition with grid­ generated turbulence of 3.8% turbulence intensity and a dissipation length scale of 1.7 inches. The following conclusions were reached: 1) The relative strengths of the asymmetric vortices can be noted by the sharp spike shape in the ambient condition; this condition becomes diffused and becomes fatter in the turbulent condition; 2) The right side vortex has greater strength than the left side one as seen by the diffusion in the total pressure coefficient and static pressure coefficient contours with and without a turbulent condition; 3) an increase in turbulence intensity tends to reduce the strength of the asymmetric nose-generated vortices; also pushes the two asymmetric vortices closer together; 4) and crossflow velocities were examined and were found to indicate the behavior denoted by the pressure contours.

Department dc:contributor.department

Aeronautics and Astronautics

Grantor dc:publisher

Monterey, California. Naval Postgraduate School

Year dc:date.issued

1988

Author dc:creator

• Lung, Ming-Hung

Advisor dc:contributor.advisor

• Howard, Richard M.

Statement dc:rights

• Copyright is reserved by the copyright owner

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/10945/23235

OAI identifier oai:identifier

oai:calhoun.nps.edu:10945/23235