An Estimation Method of Cavity Extent on a Model Propeller Considering Laminar Separation

Abstract

This paper describes an estimation method of sheet cavitaion on a model propeller considering laminar separation of boundary layer. Existence of laminar separation at the leading edge is judged using pressure distribution calculation and two-dimensional boundary layer theory.The sheet cavitation incepts when the pressure reaches below vapour pressure at the separation point. Then cavity extent in chord direction is estimated combining linear cavity theory and lift equivalent method.The estimated cavity extent agrees well with the experiment except when the cavity is at a growing condition in wake. In this case, transient effects of the separated region and cavity bubble formation seem predominant and the observed extent is sometimes much smaller than the calculated result.