A Ship's Propulsion Mechaniam of Two-Stage Weis-Fogh Type : 3rd Report, Visualization of Flowfield and Analysis of Dynamic Properties

Abstract

The flowfield of a ship's propulsion mechanism consisting of two-series of wings in a square channel is visualized by numerical simulations using the discrete vortex method and by the hydrogen bubble technique. The simulations are performed by assuming that the separations occur at the trailing edges of the wings. The streak-lines and the time-lines agree well with experimental results. The flowfield is unsteady and complex, but the properties of the flow are clarified by numerical and experimental visualization. The time histories of the thrust and the drag acting on the wings are also calculated. These calculated values agree well with the previously obtained experimental values. The effects of the interaction of the wings are explained in terms of the circulations around the wings.