Viscous effects on a sphere

AuthorSearch for:
TypeTechnical Report
Series titleLaboratory Memorandum
SubjectViscous lift; Cavitation tunnel; Sphere; America's Cup; Turbulent flow
AbstractOver the course of the past work term, I have worked extensively with the Ship Technology Group, at the National Research Council - Institute for Marine Dynamics, under the guidance of Dr. Bruce Parsons. In my capacity as Research Assistant, I was able to help plan, prepare, and conduct experiments using the facility's cavitation tunnel and later analyze the results of these experiments. Along with Research Technician, Darrell Sparkes, over 300 experimental test trials were carried out over 3 months of testing. The primary focus of these experiments was to investigate viscous drag effects on a number of models within the cavitation tunnel. Two separate series' of testing were conducted. The first set of testing involved using 3 different mounting configurations to hold a 10cm diameter sphere in the middle of the cavitation tunnel. There were a number of intended objectives at the outset of the experiment. The first objective was to observe the viscous lift and drag on the sphere. By using several mounting variations, the effects of each assembly could be gauged, and by comparison, values could be found for the sphere alone. In a second variation to this experiment, wire screens were inserted into the cavitation tunnel upstream of the test sphere. This was hoped to promote turbulent stimulation in the flow. The evidence of this could be found by comparing the lift and drag characteristics for each set-up with and without the screen. A second series of testing involved a number of foil sections, again concerning viscous drag effects. Two foil sections were tested in total; a NACA 0012 foil section and a model rudder from an America's Cup sailing yacht. Each foils was tested quite extensively. Firstly, each smooth foil was positioned at 0, 2, and 4 degrees angle of attack and the flow rates were varied from 0.5 - 6.0 m/s. Loadings such as drag, lift, roll and pitch were monitored during the tests, and fluid velocities around each foil were recorded. After this was complete, turbulent studs were added to the leading edge of each foil at various positions and pitches to stimulate turbulent flow over the foils. In each of these cases, all of the angles of the attach were repeated at each of the test speeds.
Publication date
PublisherNational Research Council Canada. Institute for Marine Dynamics
PlaceSt. John's, NL
AffiliationNRC Institute for Ocean Technology; National Research Council Canada
Peer reviewedNo
NRC number5237
NPARC number8895734
Export citationExport as RIS
Report a correctionReport a correction
Record identifierece141f7-77fb-4baf-85b3-975773858ffd
Record created2009-04-22
Record modified2016-10-03
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)