Table 1.
Ultrasonic velocity and ratios according to distance between transducers
Surface transmission length (mm)
Velocity (m/s)
Mean
COV (%)
1)
Ratio
2)
Indirect method
50
1150.1
4.46
0.26
100
3486.6
2.22
0.79
150
3777.0
2.58
0.85
200
3869.7
2.70
0.87
Direct method
4430.7
15.30
1
Coefficient of variation
Indirect method value to direct method value.