Measurements

Summary

The table below gives the average rise time of the intruder particles for all experimental conditions.

\(U\) (m/s)	\(M\) (g)	intruders	\(t_r^{(1)}\) (s)	\(t_r^{(2)}\) (s)	\(t_r^{(3)}\) (s)	\(t_r^{(4)}\) (s)	raw data
1.83	177.46	one large	7.503 \(\pm\) 0.882	na	na	na	dl
1.83	177.46	four large	7.186 \(\pm\) 1.039	7.924 \(\pm\) 1.245	8.600 \(\pm\) 2.134	9.378 \(\pm\) 1.884	dl
1.83	227.47	one large	11.919 \(\pm\) 0.939	na	na	na	dl
1.83	227.47	four large	9.211 \(\pm\) 3.010	10.751 \(\pm\) 1.446	12.756 \(\pm\) 1.240	15.406 \(\pm\) 1.799	dl
1.99	177.46	two large	5.866 \(\pm\) 0.502	6.762 \(\pm\) 0.485	na	na	dl
2.14	177.46	two large	5.491 \(\pm\) 0.752	6.666 \(\pm\) 0.838	na	na	dl
2.14	177.46	two small	9.640 \(\pm\) 1.469	11.178 \(\pm\) 1.177	na	na	dl
2.14	177.46	four large	5.152 \(\pm\) 0.312	5.540 \(\pm\) 0.487	6.123 \(\pm\) 0.610	7.042 \(\pm\) 0.812	dl

Comments

• Collapsed data: The original experiments played around with the position of intruder particle, specifically for one large intruder. It was found that there was no statistically significant difference between center and randomized placement. Therefore these two configurations have been collapsed here. Technically, the one large intruder, \(U = 1.82\) (m/s), and \(M = 177.46\) (g) and the first seven measurements of the \(M = 227.47\) (g) conditions have a center placement. All other conditions have a random placement.

• Excluded data: To further study the influence of the initial configuration, experiments were also conducted with the intruders placed in the corner of the bed and on top of a single layer of common glass beads. Unlike random vs center placement, these configurations affect the rise time. This data can be found in the Supplementary Material of LaMarche, et al. (2022)

• Error bars on the \(t_r\) mean values are 95% CIs determined from a t-test.

• Raw ascii data processed with this simple octave script