Hot Wire Measurements Applied to the Detection of the Transitional Flow in the Boundary Layer around Ship Models

Abstract

Recently, the need of measurements of the boundary layer around a ship model has been stressed in connection with turbulence stimulation used at the ship experimental tank. The author observed, formerly, the transition in the boundary layer along a flat plate by finding the velocity fluctuation through use of hot wire. And now the experiments on four ship models (2.5 m Hakubasan-Maru model, and 1.7 m series models-A, B and C) were carried out by the same method.
As a result, the state of the flow in the boundary layer around ship models was observed, and the areas of laminar, transitional and turbulent flows on ship models were determined. The effect of turbulence stimulation by a trip wire or plate studs was confirmed by this means, thereby making it clear that the area of the transition was considerable at low speed in spite of the use of these device. Moreover, it was found that the area of laminar or transitional flow was larger on the full ship model than the fine model.