Abstract:
Herein, the evolution and detailed structure of velocity and pressure fields of an
oscillating axi-symmetric pipe flow arising from a rapid closure of a valve has been
detennined through the solution, by the finite volume technique, of the full Navier
Stokes equations. The method correctly predicts the distortion of the pressure
waveform. The two-dimensional solution obtained confirms the one-dimensional
solution obtained by the method of characteristics of the two-equation model
incorporating frequency dependent friction typically used in modelling of transient
pipe flows.
The velocity field following valve closure is seen to consist of th e initial velocity
profile upon which is superimposed an oscillating velocity component. The oscillating
component is uni form in a pipe cross-section, at any instant. However, the profiles of
initial steady state flow component and the uniform oscillating flow component are
progressively distorted as the cumulative distance traversed by the wave increases