V shaped Weir

Free surface computationas over a 3D V-shaped weir

The 3D V-shaped weir was made to study numerical algorithms for computing free surface flows. Four different different algorithms were tested and compared with measurements from the physical model. Two computer programs were used: OpenFOAM and SSIIM 2. The OpenFOAM program used a fixed grid and the volume of fluid method. An animation is given below. The other three algorithms were made in the SSIIM program, using an adaptive grid that followed the free surface. The three algorithms were based on water continuity, pressure gradients and an the shallow water equations. The methods based on the pressure gradients and the shallow water equations were implicit and could use large time steps.

Weir seen from the side.

Weir seen in the downstream direction.

Download video (179 MB) of the laboratory model with water.

Download OpenFOAM animation of the weir (10 MB)

The OpenFOAM animations show a longitudinal profile of the channel and the weir with two different grids. The VOF method is used, modelling a mixture of water (blue) and air (red).

In case someone wants to compute this case with another program, the following files might be helpful:

Download STL file of the flume bed with the weir
Download measurement data on LibreOffice spreadsheet format

Reference:

Olsen, N. R. B. (2015), Four free surface algorithms for the 3D Navier-Stokes equations, Accepted to Journal of Hydroinformatics.

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This page is made by

Nils Reidar B. Olsen

NTNU
Faculty
Department

Webmaster: torove.leiknes@ntnu.no
Updated: 29. July 2015