Copyright © 2010 TDMG Inc.
All rights reserved.
(514) 381-
KNOWLEDGE CENTER
RESISTANCE OF PERFORATED PLATES
Resistance coefficients for thin-
strips with sharp
edged orifices (according to Fried & Idelchik).
Conditions:
Range of sheet length to hole diameter ratio, 0 < l/Dh < 0.015
Reynolds number, Re > 105
Where:
for is the area of one orifice.
The resistance coefficient is given by:
Open Area
Resistance Coefficient
Open Area
Resistance Coefficient
0.01
28677.936
0.51
3.729
0.02
7055.112
0.52
3.478
0.03
3085.115
0.53
3.245
0.04
1707.168
0.54
3.027
0.05
1074.657
0.55
2.824
0.06
733.924
0.56
2.635
0.07
530.188
0.57
2.458
0.08
399.066
0.58
2.293
0.09
309.930
0.59
2.138
0.10
246.716
0.60
1.993
0.11
200.347
0.61
1.858
0.12
165.385
0.62
1.731
0.13
138.414
0.63
1.613
0.14
117.203
0.64
1.501
0.15
100.243
0.65
1.397
0.16
86.487
0.66
1.299
0.17
75.190
0.67
1.207
0.18
65.810
0.68
1.121
0.19
57.944
0.69
1.040
0.20
51.291
0.70
0.964
0.21
45.620
0.71
0.892
0.22
40.751
0.72
0.825
0.23
36.544
0.73
0.762
0.24
32.888
0.74
0.703
0.25
29.693
0.75
0.647
0.26
26.888
0.76
0.595
0.27
24.413
0.77
0.546
0.28
22.221
0.78
0.500
0.29
20.273
0.79
0.457
0.30
18.534
0.80
0.416
0.31
16.976
0.81
0.378
0.32
15.578
0.82
0.343
0.33
14.318
0.83
0.309
0.34
13.181
0.84
0.278
0.35
12.150
0.85
0.249
0.36
11.215
0.86
0.221
0.37
10.364
0.87
0.196
0.38
9.589
0.88
0.172
0.39
8.880
0.89
0.150
0.40
8.232
0.90
0.129
0.41
7.637
0.91
0.110
0.42
7.091
0.92
0.093
0.43
6.589
0.93
0.076
0.44
6.126
0.94
0.062
0.45
5.700
0.95
0.048
0.46
5.305
0.96
0.036
0.47
4.941
0.97
0.025
0.48
4.603
0.98
0.015
0.49
4.290
0.99
0.007
0.50
3.999
1.00
0.000
Fried & Idelchik, Flow Resistance: A Design Guide for Engineers; Hemisphere Publishing Corporation, 1989; Diagram 8.1