The purpose of the study is to continue the investigation of the aerodynamic drag on vehicles moving in guideways of varying degrees of enclosure. The reason for the study is that several potential high-speed ground transport system concepts involve high-speed motion of vehicles in enclosed guideways for significant portions of their travel time. Both analytical and experimental investigations were carried out. The analytical studies continued the development of the solution for the aerodynamic drag on a vehicle in an enclosed guideway in laminar flow. Experimental studies were carried out using cylindrical models in circular tunnels of various length and various degrees of wall porosity. A drop testing apparatus was employed in which water was the only test fluid and results were obtained for Reynolds numbers of the order of 100,000. Results to date indicate that for vehicle length-diameter ratios of the order of 15 and above, with tunnel to vehicle diameter ratios of 1.5 and greater, a drag coefficient based on the wetted surface area of the vehicle is independent of the vehicle length-diameter ratio for incompressible flow. Results also indicate that, for incompressible flow, employing a tunnel model with a closed end simulates a tunnel length-diameter ratio of infinity. Tunnel wall porosity, assuming relatively unobstructed motion of fluid outside the porous wall, has a marked effect on decreasing the aerodynamic drag on vehicles moving in enclosed guideways and for the range of variable investigated (clearance ratio as low as 1.4) tunnel wall porosity of 20 per cent is adequate for all the significant drag reduction that is possible. (Author)

  • Corporate Authors:

    Massachusetts Institute of Technology

    Engineering Projects Laboratory
    Cambridge, MA  United States 
  • Authors:
    • Gouse, SWJ
    • Noyes, B S
    • Swarden, M C
  • Publication Date: 1967-10

Media Info

  • Pagination: 94 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00039043
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Contract Numbers: C-85-65t
  • Files: TRIS
  • Created Date: Nov 24 1973 12:00AM