Blockage correction

https://doi.org/10.1016/0029-8018(91)90014-HGet rights and content

Abstract

The velocity distribution and resistance for a body moving in a channel differs from that of in unrestricted water. A simple method has been developed to determine these velocity and resistance differences. An ellipsoid of revolution has been taken as the equivalent body from the blockage effect point of view. The motion of the equivalent ellipsoid in a rectangular channel has been studied by slender body approximation. The velocity increases have been computed numerically for different channels and velocities. Curve fitting has been applied to these velocity increases and velocity increase formulae have been obtained for different channel width-depth ratios. The resistance variation in unrestricted water can be easily obtained from values in a rectangular channel or vice versa by applying the method presented here.

References (29)

  • L.S. Artjushkov

    Wall effect correction for shallow water model tests

  • K.J. Bai

    A localised finite-element method for two-dimensional steady potential flows with a free surface

    J. Ship Res.

    (1978)
  • K.J. Bai

    Blockage correction with a free surface

    J. Fluid Mech.

    (1979)
  • J.P. Comstock et al.

    The effect of size of towing tank on model resistance

  • J.E.C. Conn et al.

    BSRA resistance experiments on the Lucy Ashton

  • O. Durgun

    Determination of the blockage effect in channels

    ITÜ dissertation

    (1983)
  • I.S. Gradshteyn et al.

    Table of Integrals Series and Products

    (1965)
  • T.H. Havelock

    The approximate calculation of wave resistance at high speeds

  • G. Hughes

    The effect of model and tank size in two series of resistance tests

  • G. Hughes

    The boundary effect on model resistance

  • M. Kirsch

    Shallow water and channel effects on wave resistance

    J. Ship Res.

    (1966)
  • A.A. Kostyukov

    Theory of Ship Wave and Wave Resistance

  • H. Lamb

    On the effect of the walls of an experimental tank on the resistance of a model

    British ARC, R. and M.

    (1926)
  • M. Lock

    The interference of a wind tunnel on a symmetrical body

    British ARC, R. and M.

    (1929)
  • View full text