Fisheries Engineering

Study of Intemal Tides in Nomi Bay-Ⅰ

Observations and Theoretical Consideration

Seiya HAGINO

1992 Volume 29 Issue 1 Pages 1-8
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_1

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The tidal currents associated with temperture and salinity fluctuations have been observed at Nomi Bay. The period of intemal tides is close to the natural period in the bay, causing the resonance. It is indicated that the vertical displacement of the transition layer by resonance is larger than that of the sea surface. The horizontal tidal flow of the upper layer is approximately opposite to the flow of the lower layer. Those phenomena showed that intemal tides are predominant in the bay. The sea water exchange is dominantly affected by the resonance of intemal tide. The exchange ratio is much larger than weakly stratified bays. Especially, the resonance of ihtemal tide plays a crucial role in making the culture of young ye1lowtails, etc. a possibility. The behaviors of the internal tides are examined analytically by a two-layer linear model. It is estimated that resonance of intemal tide occur at Nomi Bay. The displacement of the interface and the velocities of upper and lower layers are calculated. These estimated values are verified by the observed values at Nomi Bay.

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Study of Intemal Tides in Nomi Bay-Ⅱ

Numerical Experiments and Application to the Improvement of Seawater Quality

Seiya HAGINO

1992 Volume 29 Issue 1 Pages 9-16
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_9

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The oceanographical conditions due to intemal tides which have been observed at Nomi Bay are examined by a numerical experiment with a two-layer stratified flow model. When the fluctuations of surface tide and the interface are given with the inversion phase at the mouth of Susaki Bay, the intemal tides are amplified and the stratified flows are formed. The computed values are consist with the observed values of current velocities and the amplitude of the intemal tides. It is indicated that the amplification of the intemal tides at Nomi Bay is considered to be due to the resonance phenomenon and is closely related to the local bottom topography. A method for the improvement of water quality in area such as a mariculture ground where the intemal Waves intrude into a shelf is discussed. The effectiveness of the enhanced sea water exchange by density current ditch is examined by a bydrauric experimental model. The effectiveness is estimated to be stronger when the thickness of lower layer is thimer and the bottom friction stress is larger.

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Durability of Combustion Chamber Sliding Parts of the Main Engine of a Fishery Training Ship

Hayao AKIZAWA, Sadami YADA, Makio SAKAMOTO, Hiroaki YONEMOTO, Hisaharu ...

1992 Volume 29 Issue 1 Pages 17-22
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_17

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[in Japanese]

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A Study on Upwelling Vortices behind a Three-Dimensional Obstacle

Tatsuo SUZUKI

1992 Volume 29 Issue 1 Pages 23-30
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_23

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To study the flow structure arround natural reef, Water flume experiment was carried out. The following results were obtaind. 1) Granulor dye scattering method was very useful to visualize the flow pattems arround a three-dimensional obstacle. 2) The mechanism of upwelling vortex generation is completely different between two-dimensional model and three-dimensional model. 3) An obstacle whose length is between 6 and 8 times of its height generates strong upwelling vortex behind its recirculating zone. The height of upwe11ing vortex is more than 4 times of the height of the obstacle. 4) Dual cones type model generates strong upwelling vortex effectively compared with other mound type model. The tidal currents associated with temperture and salinity fluctuations have been observed at Nomi Bay.

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Recent Situation on the Japanese Littleneck Fisheries

Jun KAKINO

1992 Volume 29 Issue 1 Pages 31-39
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_31

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Reclamation of Seabed for the Japanese Littleneck Tapes philippinarrum in Matsushima Bay

Keiichi SAKAI, Kiyotaka TAKAHASHI

1992 Volume 29 Issue 1 Pages 41-45
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_41

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Sexual Maturation and Spawning of Japanese Littleneck Tapes philippinarum Collected from Tokyo Bay

Mitsuharu TOBA, Yo NATSUME, Hiroshi YAMAKAWA

1992 Volume 29 Issue 1 Pages 47-53
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_47

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Selective Settlement of Japanese Littleneck Larvae and Their Distribution in Mikawa Bay

Shigeaki YANAGIBASHI

1992 Volume 29 Issue 1 Pages 55-59
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_55

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The Growth and Mortality of Japanese Littleneck Tape phillipinarum on Banzu Tidal Flat, Tokyo Bay

Tadashi NISHIZAWA, Jun KAKINO, Kisaburo NAKATA, Koichi TAGUCHI

1992 Volume 29 Issue 1 Pages 61-68
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_61

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Marine Bio-Production and Environmental Preservation in a Bay

Makoto NAKAMURA

1992 Volume 29 Issue 1 Pages 69-72
Published: 1992
Released on J-STAGE: December 01, 2017

DOIhttps://doi.org/10.18903/fisheng.29.1_69

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