蛙又結節網地の投影面積

抄録

The purpose of this experiment is to obtain the experimental equation concerning the projective area of a Weaver's knot-netting as the basic research for the study of fluid dynamical coefficient at any attack angleθ, when the netting is set into a flow.
The netting samples used for the experiments are six kinds of netting of twine diameter d and leg length l. And, in addition to this, hanging angle ∅ is changed at six stages concerning one netting. The projective area is measured the same way as in the case of knotless twisted netting.
Results obtained are as follows:
(1) The projective area of a twine-portion on the (i×j) mesh netting sample, at the range of attack angle Θ^∗<θ ?? 90° is derived in the following experimental equation.
S"_θ=4ijd(l-3.03d)(0.16dl+0.51)sinδsin^dθ+6.08d²(2ij+i+j)
(2) The projective area of a twine-portion on the (i×j) mesh netting sample, at the range of attck angle Θ<θ ?? Θ^∗ is derived in the following experimental equation.
S"_Θ^∗=3.68ijd(l-3.03d)/(0.16dl+0.51)sinδsin^dθ+6.08d²{(1.84ij+i-j-1)(θ/Θ^∗)+2j+1}
(3) And concerning the range of attack angle 0° ?? θ ?? Θ, it is possible to represent in the following experimenta equation.
S"_Θ=0.88[(2ij-j)l²sin2∅sinθ+2jd(l-3.03d)sinδ+6.08d²{(2j+1)+(i-1)(θ/Θ^∗)}]
Where,
Θ^∗: Attack angle when the adjacent knots touched each other on a projected plane.
S"_θ: Projective area of the twine-portion of the Weaver's knot-netting at the range of attack angle Θ^∗<θ ?? 90°.
S"_Θ^∗: Projective area of the twine-portion of the Weaver's knot-netting at the range of attack angle Θ<θ ?? Θ^∗.
S"_θ Projective area of twine-portion of the Weaver's knot-netting at the range of attack angle 0° ?? θ ?? Θ.