ijssel model wet test

ijssel model wet test
wet test of the ijssel

Run the river wild.

Wet test of 1 to 30000 model of the IJssel, with exaggerated width of river to avoid hydraulical problems due to the small size. It looks nice, has a usefull size of 2.5 m x 1 m, which is very suitable. The audience of the demo can gather around it and it has a proper size for eventual hands-on work.

It takes 30 seconds for the water to flow from the inlet (IJsselkop Westervoort) to the lowest point (Keteldiep), which in reality takes about 1 day. So time scale is about 1 to 3000, or one model day = 30 seconds. The XY (horizontal) scale 1 to 30000 and Z (vertical) scale is 1 to 250. Width of channel 5 cm (downstream) and 3 cm (upstream) , depth 1.5 (up) cm and 1.1 (down) cm. These makes the model usable for demo purposes. It does not work to0 fast or too slow, size is all right, and it offers a nice overview.

Calculated the Manning number M from measured discharge , inclination and dimensions of the channel, M = 40. This can be used in the formula to calculate a better downstream width. Only a slight adaptation of the width downstream is necessary: it must be 4 cm, then depth over the whole river will be identical (1.5 cm). Numbers, numbers, numbers, all necessary to get it right.