Table 2. Characteristics of the surface deformation for 0.5%, 1%, 2%, and 5% gels. In the first set of data, the wave propagation velocity is experimentally measured and used to estimate values for the shear modulus G and hence the parameter C. The location of the transition from prograde to retrograde particle rotation, scaled by the bubble radius, is also reported. The second, third, and fourth sets of data are model predictions. In all cases, numerical simulations are used to estimate the wave propagation velocity and the location of the transition from pro- to retrograde rotation. In the second set of data, the shear modulus estimated from wave propagation velocity is used as input for the model. In the third set of data, the value of C is varied to obtain a closer fit to the experimental data. In the fourth set of data, the shear modulus measured from a creep test is used as input for the model.

Gel concentration	0.5%	1%	2%	5%
Wave propagation velocity from experiment (m s–1)	N/A	11	18	40
Shear modulus G estimated from velocity (kPa)	N/A	133	355	1754
Non-dimensional shear wave speed C from experiment	N/A	0.57	0.94	2.1
Location of pro- to retrograde transition from experiment	1.2	1.3	2.2	4.3
Wave propagation velocity from model (m s–1)	N/A	12	23	44
Location of pro- to retrograde transition from model	N/A	3	4.2	6.5
Shear modulus G from fit (kPa)	26	50	101	1617
Non-dimensional shear wave speed C	0.25	0.35	0.5	2.0
Wave propagation velocity from fit (m s–1)	5.9	9.3	11	43
Location of pro- to retrograde transition from fit	N/A	5.6	2.9	6.4
Shear modulus G from creep test (kPa)	1.4	4.7	43	318
Non-dimensional shear wave speed C	0.06	0.11	0.33	0.89
Wave propagation velocity from model (m s–1)	N/A	N/A	8.8	22
Location of pro- to retrograde transition from model	N/A	N/A	7.9	4.1