Accession Number:

ADA214014

Title:

Nonlinear Viscous Waves Produced by an Impulsively Moving Plate

Descriptive Note:

Technical rept. 1 Feb-30 Sep 1989

Corporate Author:

IOWA INST OF HYDRAULIC RESEARCH IOWA CITY

Personal Author(s):

Report Date:

1989-09-01

Pagination or Media Count:

86.0

Abstract:

The free surface flow generated by an impulsively accelerating, surface-piercing, vertical plate has been studied numerically as well as experimentally. The two dimensional, unsteady Navier Stokes equations are discretized using the finite analytic scheme which incorporates the analytic solution into the locally linearized differential equations. The continuity equation and the dynamic boundary conditions on normal and tangential stresses at the free surface are applied to determine the pressure and two velocity components at the free surface. The kinematic boundary condition on the free surface provides the movement of the free surface. A series of experiments is carried out. The flat vertical plate is fixed on a towing carriage which is set off by suddenly dropping a weight bucket through a connecting steel cable in a pulley system. A data acquisition system is used for controlling the sampling process and for recording the signal output. The agreement of the free-surface profile and the pressure distribution between the numerical results and the experimental measurements is fairly good. The mathematical singularity, which is predicted by the potential-flow theory, at the contact line between the plate and the free surface is not observed in the physical experiments. The water surface in front of the vertical plate simply rises up during the initial stage of the acceleration of the plate.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE