Snow Samplerの押込抵抗について

実地試験

抄録

The tooth-cutter of a snow sampler gives little effect in lessening the resistance when penetrated into snow.
This value of resistance is given by
π/2ξ f'DS²/sin2θ+ (sinθ+μcosθ)
and is proportioned to DS² and not influenced so much by θ, the edge angle. To make the resistance less it is necessay to make D (the maximum outer diameter) and S (the thickness of the pipe) little and thin as possible.
We had made a theoretical comparison of DS² between the “53 Kamuro Type Snow Sampler” made on the basis of the above mentioned theory, and the other types of the snow sampler*. And this time we practically examined how are the penetrating resistances in the Kamuro Type and the other two types (S type and Y type).
S type has the tooth-cutter and its sectional area at the edge is 20 cm² : the same as that of the Kamuro type, and Y type has the knife (horizontal) edge with the sectional area 12.25 cm².
The value of the Initial Resistance, in the case of the mean density of 0.60, and the depth of 150 cm, was-
Kamuro type S type Y type
0.37 kg/cm 1.11 kg/cm 0.48 kg/cm
Comparing each DS², the Kamuro type as the standard, we had the results shown below.
Theoretical Value (A) Examined V. (B) B/A
S Type 5.5 4., 2 0.76
S Type (revolved) 4.3 3.0 0.70
Y Type 1.5 1.3 0.87
And at the same examination we observed the Kamuro type is superior to the other types in the efficiency of gathering snow.
Tadayuki Ounuma, 1958, On the Resistance in penetrating the Snow Sampler “53 Kamuro Type Snow Sampler” seppyo Vol. 20. No.3, Journal of the Japanese Society of Snow and Ice.