Numéro : 2094 - Year : 1989
Turbulent limit layer along a ship and its effect on the propeller
R.LEGENDRE, Ingénieur Général de l' Armement (GM)Membre de l' Académie des Sciences , Vice-Président de l'ATMA.
The boundary layer that develops along a ship hull contains large eddies whose mean diameters are almost equivalent to the thickness of the layer. Since the diameters increase as the eddies approach the propeller, they do disturb propeller operation.
On the basis of in-depth observations. an explanation is proposed for how eddies form and increase in circulation. but for the time being there is no way of calculating the phenomenon. nor its effects on the propeller. A simplification is therefore needed, replacing eddies with their axes. if we want to determine the order of magnitude of this effect.
There currently exist methods of calculation, already in use in aeronautics, for estimating the unsteady hydrodynamic forces exerted on the propeller blade. The reader is referred to previous publications concerning the estimation of eddy noise emissions.
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