Abstract
A towing live fish preserve is used for carrying the fish that are caught to a port of landing while the fish are
alive. Research into the live fish preserve is needed because the demand for live fish is increasing. This research
concems preserve used for carrying sardine at Nobase in Yamaguchi prefecture. The user requested the improvement of the flow in the preserve. We performed experiments using a one-tenth model of an actual preserve as the basic preserve in a circulating water tank. First, We cleared the flow in the basic preserve by the tuft grid
method. Then, we measured the drag force. Secondly, we improved the preserve by making many holes on the
bow-shaped cover in front of the preserve. The area ratios of the holes to the cover were 2. 2%, 7. 5%, and
15. 9%. We repeated the same experiments using these improved preserves. By the tuft grid method, a large
vortex was confimed in the basic preserve. The vortex changed only slightly to the area ratios of 2. 2% or 7. 5%.
But at the area ratio of 15. 9%, the vortex disappeared and the flow in the preserve became moderate and unifom
asawhole.
