Table 2.

Grid convergence test for CH CFD of monosized and polysized GS combinations

Case	Diameter of GS	Number of cells	Permeability		Relative error
	(mm)	(million)	(m s$_{}^{-1}$)	($\times$10-9 m2)	(%)
1	8	1.44	0.0181	1.85	33.00
		3.10	0.0250	2.55	7.44
		5.90	0.0266	2.71	1.75
		9.80	0.0271	2.76	–
2	6	4.90	0.0180	1.83	18.02
		8.40	0.0206	2.10	6.05
		13.30	0.0213	2.17	2.59
		17.50	0.0219	2.23	–
3	4	13.80	0.0127	1.29	18.22
		18.90	0.0145	1.48	6.55
		24.80	0.0152	1.55	2.47
		31.60	0.0156	1.59	–
4	2	56.50	0.0044	0.45	37.00
		87.00	0.0062	0.63	11.50
		105.00	0.0067	0.68	3.50
		124.00	0.0070	0.71	–
5	Polysized volume ratio 10:20:70	17.20	0.0225	2.29	4.14
		19.20	0.0231	2.35	1.56
		22.90	0.0233	2.38	0.40
		28.30	0.0234	2.39	–
6	Polysized volume ratio 20:10:70	16.90	0.0207	2.11	4.70
		19.40	0.0213	2.17	1.90
		23.50	0.0216	2.20	0.53
		29.00	0.0217	2.21	–
7	Polysized volume ratio 10:70:20	17.10	0.0205	2.09	4.67
		20.00	0.0210	2.14	2.04
		24.30	0.0214	2.18	0.51
		30.00	0.0215	2.19	–
8	Polysized volume ratio 20:70:10	16.70	0.0189	1.93	5.76
		20.20	0.0195	1.99	2.70
		24.80	0.0199	2.03	0.81
		30.10	0.0201	2.05	–
9	Polysized volume ratio 70:10:20	15.10	0.0155	1.58	10.65
		20.80	0.0166	1.69	4.73
		26.60	0.0171	1.74	1.70
		33.50	0.0174	1.77	–
10	Polysized volume ratio 70:20:10	15.10	0.0155	1.58	10.42
		20.80	0.0165	1.68	4.87
		26.70	0.0170	1.73	1.75
		33.70	0.0173	1.76	–
11	Polysized volume ratio 33:33:34	16.70	0.0186	1.90	6.33
		20.30	0.0193	1.97	2.75
		25.20	0.0197	2.01	0.75
		31.40	0.0199	2.03	–