This report clarifies the surface areas of knotted netting, especially on knot which plays an important role for carrying out fluid-dynamical studies on netting fabrics.
In this study, the so-called “knot” is defined as a tied portion of the twine including short legs, provided that the legs are cut veritcally along a normal direction under a condition of stretched mesh.
The nettings used are made of Weaver's knot and reef knot, with the three-ply z-twist polyethylene twine.
The surface area of a knot is obtained by measuring the circumference of cross-section of a paraffin-knot-model, with curvimeter.
Results obtained are as follows:
1) Netting surface area S
sw of Weaver's knot is represented as following experimental equation.
S
sw=2
ij{2Q(
l-3.87
d)+31.67
d2}+31.67
d2(
i+
j)
2) Netting surface area S
sr of the reef knot is represented as following experimental equation. S
sr=2
ij{2Q(
l-3.42
d)+26.31
d2}+26.31
d2(
i+
j)
Where each symbol is as follows,
d: diameter of twine,
i: mesh numbers along the twinewise direction,
j: mesh numbers along the normal direction,
l: length of a leg, Q: circumference of a twine, S
sr: surface area of the (
i×
j) meshes reef knot netting, S
sw: surface area of the (
i×
j) meshes Weaver's knot netting.
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