生物が付着したホタテ養殖籠の流水抵抗について

山本 勝太郎; 平石 智徳; 小島 隆人

doi:10.2331/suisan.54.1913

Drag of a Net Cage Encrusted with Marine Organisms in Scallop Culture

Katsutaro Yamamoto, Tomonori Hiraishi, Takahito Kojima

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JOURNAL FREE ACCESS

1988 Volume 54 Issue 11 Pages 1913-1918

DOI https://doi.org/10.2331/suisan.54.1913

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Published: November 25, 1988 Received: June 03, 1988 Available on J-STAGE: February 29, 2008 Accepted: - Advance online publication: - Revised: -
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Date of correction: February 29, 2008 Reason for correction: - Correction: ABSTRACT Details: Wrong : Net cages become inevitably encrusted with marine organisms in scallop culture. The darg of the net cage composed of 10 compartments (0.5m in diameter and 2m high, covered with 0.8mm polyethylene mono-filament net of mesh size 4.0cm) encrusted with marine organisms is still not sufficiently clear. In this study, we measured the drag of three net cages (named cage A, cage B and unused cage) with different encrusted conditions of marine organisms in an experimental tank. The cage A was suspended by a main rope in an actual scallop culture facility for 3.5 months in winter season and marine organisms weighed 0.62kg in water without scallops. The cage B was used by a scallop culturist over a period of 14 months in the same facility, and its overall weight in the water consisted of 1.6kg of cage, 5.5kg of 100 scallops grown up to average size of 120mm, and 2.4kg of marine organisms. The unused cage was an empty new cage.
The experimental results were drawn in C_D-R_e diagrams (C_D: drag coefficient, Re: Reynolds number) For each of the three cages the change of C_D to Re was small within the experimental range of 5.0×104<Re<3.0×105. The mean value of C_D was 1.2 for cage A, 1.9 for cage B and 0.39 for the unused cage when set in normal to the water flow and 1.6, 1.8 and 1.4 when set in parallel, respectively.
Right : Net cages become inevitably encrusted with marine organisms in scallop culture. The darg of the net cage composed of 10 compartments (0.5m in diameter and 2m high, covered with 0.8mm polyethylene mono-filament net of mesh size 4.0cm) encrusted with marine organisms is still not sufficiently clear. In this study, we measured the drag of three net cages (named cage A, cage B and unused cage) with different encrusted conditions of marine organisms in an experimental tank. The cage A was suspended by a main rope in an actual scallop culture facility for 3.5 months in winter season and marine organisms weighed 0.62kg in water without scallops. The cage B was used by a scallop culturist over a period of 14 months in the same facility, and its overall weight in the water consisted of 1.6kg of cage, 5.5kg of 100 scallops grown up to average size of 120mm, and 2.4kg of marine organisms. The unused cage was an empty new cage.
The experimental results were drawn in C_D-R_e diagrams (C_D: drag coefficient, Re: Reynolds number) For each of the three cages the change of C_D to Re was small within the experimental range of 5.0×104<Re<3.0×105. The mean value of C_D was 1.2 for cage A, 1.9 for cage B and 0.39 for the unused cage when set in normal to the water flow and 1.6, 1.8 and 1.4 when set in parallel, respectively.

Date of correction: February 29, 2008 Reason for correction: - Correction: PDF FILE Details: -

Abstract

Net cages become inevitably encrusted with marine organisms in scallop culture. The darg of the net cage composed of 10 compartments (0.5m in diameter and 2m high, covered with 0.8mm polyethylene mono-filament net of mesh size 4.0cm) encrusted with marine organisms is still not sufficiently clear. In this study, we measured the drag of three net cages (named cage A, cage B and unused cage) with different encrusted conditions of marine organisms in an experimental tank. The cage A was suspended by a main rope in an actual scallop culture facility for 3.5 months in winter season and marine organisms weighed 0.62kg in water without scallops. The cage B was used by a scallop culturist over a period of 14 months in the same facility, and its overall weight in the water consisted of 1.6kg of cage, 5.5kg of 100 scallops grown up to average size of 120mm, and 2.4kg of marine organisms. The unused cage was an empty new cage.
The experimental results were drawn in C_D-R_e diagrams (C_D: drag coefficient, Re: Reynolds number) For each of the three cages the change of C_D to Re was small within the experimental range of 5.0×104<Re<3.0×105. The mean value of C_D was 1.2 for cage A, 1.9 for cage B and 0.39 for the unused cage when set in normal to the water flow and 1.6, 1.8 and 1.4 when set in parallel, respectively.

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