Drag measurements on a laminar-flow body of revolution in the 13-inch magnetic suspension and balance system
Low speed wind tunnel drag force measurements were taken on a laminar flow body of revolution free of support interference. This body was tested at zero incidence in the NASA Langley 13 in. Magnetic Suspension and Balance System (MSBS). The primary objective of these tests was to substantiate the drag force measuring capabilities of the 13 in. MSBS. The drag force calibrations and wind-on repeatability data provide a means of assessing these capabilities. Additional investigations include: (1) the effects of fixing transition; (2) the effects of fins installed in the tail; and (3) surface flow visualization using both liquid crystals and oil flow. Also two simple drag prediction codes were used to assess their usefulness in estimating overall body drag.
Studies Related to the Design of a Magnetic Suspension and Balance System for an Ultra-High Reynolds Number Flow Facility
STUDIES RELATED TO THE DESIGN OF A MAGNETIC SUSPENSION AND BALANCE SYSTEM FOR AN ULTRA-HIGH REYNOLDS NUMBER FLOW FACILITY Oscar Magno Michael Gomeiz Old Dominion University, 1999 Director: Dr. Colin P. Britcher The basic design principles for a magnetic suspension and balance system applied to the test section o f an ultra-high Reynolds number facility are defined. The design o f the cross-sectional area to be used in the test section is analyzed. The parameters o f the permanent magnet to be used in the model inside the test section are investigated. The testing of magnetic fields at the center o f a test pipe and validation o f data by computer finite element analysis is described with the purpose o f finding common results. The performance o f the magnet configuration is evaluated with relation to the magnetic fields needed at the center o f the test section. Once different cross-sectional design envelopes were analyzed for the largest possible cross-sectional area, a modified octagonal crosssection was found to meet the requirements. By the use o f AutoCADTM, the parameters to be used for the permanent magnet inside the model were determined. The experimental data obtained for the magnetic fields at the center o f a test pipe was validated by the computational data by showing these results to be similar. It was also observed that the magnet configuration most likely to provide the magnetic fields needed at the center o f the test section would be: Two large coils around the test section, two coils on top and two coils underneath, and two coils to each side o f the test section. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. This thesis is dedicated with greatest love and affection to my wife, Jennifer Gomeiz. I could not have written this thesis without her unending support and patience. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Statistical theory of turbulenc
Since the time of Osborne Reynolds it has been known that turbulence produces virtual mean stresses which are proportional to the coefficient of correlation between the components of turbulent velocity at a fixed point in two perpendicular directions. The significance of correlation between the velocity of a particle at one time and that of the same particle at a later time, or between simultaneous velocities at two fixed points was discussed in 1921 by the present writer in a theory of “Diffusion by Continuous Movements.” The recent improvements in the technique of measuring turbulence have made it possible actually to measure some of the quantities envisaged in the theory and thus to verify some of the relationships then put forward. The theory has also been developed in several directions which were not originally contemplated. The theory, as originally put forward, provided a method for defining the scale of turbulence when the motion is defined in the Lagrangian manner, and showed how this scale is related to diffusion. It is now shown that it can be applied either to the Lagrangian or to the Eulerian conceptions of fluid flow.