Influences of fluid accelerations on the threshold of motion

Experiment to measure stone stability under accelarating flow. During the experiment 78 test series have been performed with changing wave steepnesses in order to create scenarios of similar horizontal near-bed velocities, but with different accelerations. Another 22 of such tests series have been carried out with stones that have a smaller diameter. It has been assumed that if there is a relation between the threshold of motion and accelerations then for some combinations of a velocity and acceleration there are stones that move while in other cases with the same near-bed velocities, but a lower acceleration, there will be no movement of the same stones.