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16.4. Angle of wall friction
Tables below contain values of coefficient of friction of granular material,
µ = tg 3 w , against stainless steel, galvanized steel and concrete of B30 class calculated
from of the angle of wall friction, ϕ w , for the evaluation of flow assessment
determined according to the tilting table method for the normal pressure ranging
from 0.5 to 2.5 kPa.
Table 16.17. Mean values (±St. Dev.) of the friction coefficient µ of wheat grain variety Begra at
the moisture content of 10-20% against stainless steel, galvanized steel and concrete B30 determined
at the normal pressure of 0.5-2.5 kPa
Moisture
content (%)
10
12.5
15
17.5
20
Normal stress
(kPa)
0.5
1.0
1.5
2.1
2.5
0.5
1.0
1.5
2.1
2.5
0.5
1.0
1.5
2.1
2.5
0.5
1.0
1.5
2.1
2.5
0.5
1.0
1.5
2.1
2.5
Coefficient of friction µ
Stainless steel Galvanized steel Concrete B30
0.282 ± 0.005
0.275 ± 0.007
0.249 ± 0.002
0.260 ± 0.004
0.257 ± 0.003
0.265 ± 0.010
0.248 ± 0.009
0.269 ± 0.008
0.259 ± 0.010
0.262 ± 0.009
0.335 ± 0.003
0.310 ± 0.003
0.280 ± 0.003
0.287 ± 0.004
0.292 ± 0.008
0.383 ± 0.003
0.344 ± 0.004
0.323 ± 0.005
0.326 ± 0.001
0.313 ± 0.007
0.414 ± 0.003
0.375 ± 0.009
0.346 ± 0.004
0.341 ± 0.009
0.335 ± 0.012
0.32 ± 0.005
0.30 ± 0.008
0.27 ± 0.004
0.26 ± 0.003
0.23 ± 0.011
0.34 ± 0.007
0.31 ± 0.011
0.28 ± 0.008
0.27 ± 0.004
0.26 ± 0.006
0.34 ± 0.013
0.33 ± 0.003
0.31 ± 0.013
0.29 ± 0.003
0.26 ± 0.021
0.42 ± 0.016
0.41 ± 0.019
0.42 ± 0.022
0.37 ± 0.016
0.35 ± 0.017
0.44 ± 0.007
0.42 ± 0.003
0.41 ± 0.007
0.40 ± 0.009
0.34 ± 0.026
0.422 ±0.010
0.388 ± 0.012
0.425 ± 0.015
0.399 ± 0.013
0.409 ± 0.022
0.379 ± 0.006
0.438 ± 0.012
0.408 ± 0.015
0.458 ± 0.016
0.434 ± 0.010
0.476 ± 0.011
0.458 ± 0.006
0.441 ± 0.026
0.476 ± 0.011
0.462 ± 0.013
0.479 ± 0.012
0.494 ± 0.013
0.472 ± 0.006
0.527 ± 0.006
0.494 ± 0.013
0.536 ± 0.050
0.546 ± 0.007
0.483 ± 0.006
0.527 ± 0.006
0.508 ± 0.011