The Actualised Sigmaplan plans the construction of Flood Control Areas with Controlled Reduced Tide (FCA-CRT) along the rivers of the Flemish part of the Scheldt estuary to protect the estuary against storm surges. A large part of the existing and future FCA-CRTs implements combined inlet-outlet sluices in the design. Flanders Hydraulics Research conducts a hydraulic revision of those combined inlet-outlet sluice. A part of this hydraulic revision deals with ventilation of the falling nappe and the use of stop log weirs in the inlet sluice.This thesis studies the effect of (non-)ventilation and the use of stop log weirs on the trajectory and other characteristic values of the falling nappe. A literature survey of the important formulae and phenomena concerning the falling nappe is conducted. Predictions of the trajectory and characteristic values of the falling nappe are made, using semi-empirical formulae.
Based on the design of four combined inlet-outlet sluices, a scale model is designed. 23 different scale model configurations are tested for a range of water heights, resulting in a total of 86 tests. A series of measurements result in dimensionless plots of the discharge coefficient and characteristic values of the falling nappe like pool depth, drop length, water depth downstream of jet impact, brink depth, ...
A computer algorithm is written to automatically detect the upper nappe profile in the recordings of the nappe with a powerful industrial camera. The computer algorithm makes it possible to plot 90% intervals of the detected upper nappe profiles for different scale model configurations.
