Elsevier

European Journal of Mechanics - B/Fluids

Volume 25, Issue 6, November–December 2006, Pages 923-938
European Journal of Mechanics - B/Fluids

Underbody and ground effects on rotating disc flow: a global scale inviscid study

https://doi.org/10.1016/j.euromechflu.2005.08.002Get rights and content

Abstract

The flow induced by a finite disc rotating near horizontal ground is considered, including the effects of an underbody. This paper concentrates on determining the shape of the free layer beyond the rim of the disc which is horizontal in the absence of the underbody and ground but forced to deform to ensure that conditions across the layer are satisfied when the underbody or ground is added. The far-field behaviour, the inviscid flow produced by a nominally infinite disc near the ground and the global solution for small ground clearances are considered analytically, and the full problem is posed as an integral problem. This is then solved numerically and analytically. Results are presented for various heights of the disc above the ground and for discs with an axisymmetric underbody present. A universal form is found for the farfield shape (which is controlled by entrainment into the free layer) but both the underbody and the ground effects are found to increase very significantly for reduced clearances.

References (27)

  • R. Debuchy et al.

    Radial inflow between a rotating and a stationary disc

    Eur. J. Mech. B Fluids

    (1998)
  • J.L. Hess et al.

    Calculation of potential flow about arbitrary bodies

    Prog. Aero. Sci.

    (1967)
  • A.R.S. Bramwell

    Helicopter Dynamics

    (1976)
  • J. Seddon

    Basic Helicopter Dynamics

    (1990)
  • S. Newman

    The Foundations of Helicopter Flight

    (1994)
  • A.T. Conlisk

    Modern helicopter aerodynamics

    Annu. Rev. Fluid Mech.

    (1997)
  • J. Zbrozek, Ground effect on the lifting rotor, Aero. Res. Counc. Rep. and Memor, no....
  • S.E. Widnall et al.

    An analytical solution for two and three dimensional wings in ground effect

    J. Fluid Mech.

    (1970)
  • M.J. Lighthill

    A simple fluid flow model of ground effect on hovering

    J. Fluid Mech.

    (1979)
  • J.N. Newman

    Analysis of small-aspect-ration lifting surfaces in ground effect

    J. Fluid Mech.

    (1982)
  • E.O. Tuck et al.

    Sliding sheets: lubrication with comparable viscous and inertia forces

    J. Fluid Mech.

    (1983)
  • M.A. Jones, Mechanisms in wing-in ground effect aerodynamics, Ph.D. Thesis, University of London,...
  • M.A. Jones et al.

    Fluid motion for car undertrays in ground effect

    J. Engrg. Math.

    (2002)
  • Cited by (0)

    View full text