Research Outputs

Innovative components

A new measurement method for continuous detection of bed forms in movable bed laboratory experiments is presented and tested, which allows to measure bed forms during morphodynamic experiments, making use of a line laser and a 3-D camera. We conclude that the absolute measurement error increases with increasing flow velocity, its standard deviation increases with water depth and flow velocity, and the percentage of missing values increases with water depth. The quality of the data remains high when a robust LOESS filter is used. This is promising for bed form tracking applications in laboratory experiments, especially when lightweight sediments like polystyrene are used, which require smaller flow velocities to achieve dynamic similarity to the prototype.

Findings and implications to practice

The use of a line laser scanner system in combination with the application of suitable filtering technique, allows for quick monitoring of the bed at high accuracy in moving bed laboratory experiments.

As example result, the right colour plot shows the measured bed level (unfiltered) as well as the longitudinal and transverse bed profile along the black lines. For the profile data, blue dots indicate raw measurements, whereas red curves show the filtered results. The top half shows the results for experiment 4 (sand) and the bottom half for experiment 5 (polystyrene). Source: (Figure 10, de Ruijsscher et al. 2018)