Numerical Prediction of Propeller Scale Effect
Numerical Prediction of Propeller Scale Effect
An extensive numerical study of the viscous flow field around marine propeller blades was undertaken, leading to a better understanding of the complex interacting flow mechanisms. The principal findings relate to propeller scale effects. Evidence was obtained and conclusions deduced by comparing the differences in the flow fields around a number of different propellers at both model and full scale sizes.
To give confidence to the method and procedure, an extensive programme of mesh sensitivity studies was undertaken to identify mesh dependency and the correct size and node distributions required to obtain stable and reliable solutions. The effect of mesh type and size was investigated for different types of flow features requiring predictions of blade wake and tip vortex flows. The quality of the leading edge, blade wake and tip vortex flows was found to be directly dependent on the quality of the mesh used in these regions.
An evaluation study was undertaken to demonstrate both the level of accuracy of the numerical techniques used and type of predictions that could be obtained. The predictions show close agreement with model test results with good agreement being achieved between velocity predictions through the blade row and in the wake and tip regions.
Propeller scale effects, due to difference in Reynolds number, were investigated numerically using solutions derived from a Reynolds Average Navier-Stokes Equations (RANS) code. The scale effect was investigated for five different propeller geometries, including straight and skewed propeller blades. A number of complex flow features were identified, resulting in changes to the propulsion performance because of dependence on Reynolds number. These dependencies are associated with viscous scaling in the vortex flow regions, with the lower Reynolds number flows having higher damping compared to higher Reynolds number flows. The latter generated stronger tip vortex flows compared to the lower Reynolds number flows. Also identified were flow separation regions, which were not identified using non-viscous Euler equation solutions. The cause of the flow separation was correlated with the complex warping of the blade surface due to principal propeller parameters of blade skew, rake, pitch, thickness and camber.
University of Southampton
Stanier, Michael John
0f63f5f6-ffda-495b-a40f-6c03259b4ec9
2002
Stanier, Michael John
0f63f5f6-ffda-495b-a40f-6c03259b4ec9
Stanier, Michael John
(2002)
Numerical Prediction of Propeller Scale Effect.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
An extensive numerical study of the viscous flow field around marine propeller blades was undertaken, leading to a better understanding of the complex interacting flow mechanisms. The principal findings relate to propeller scale effects. Evidence was obtained and conclusions deduced by comparing the differences in the flow fields around a number of different propellers at both model and full scale sizes.
To give confidence to the method and procedure, an extensive programme of mesh sensitivity studies was undertaken to identify mesh dependency and the correct size and node distributions required to obtain stable and reliable solutions. The effect of mesh type and size was investigated for different types of flow features requiring predictions of blade wake and tip vortex flows. The quality of the leading edge, blade wake and tip vortex flows was found to be directly dependent on the quality of the mesh used in these regions.
An evaluation study was undertaken to demonstrate both the level of accuracy of the numerical techniques used and type of predictions that could be obtained. The predictions show close agreement with model test results with good agreement being achieved between velocity predictions through the blade row and in the wake and tip regions.
Propeller scale effects, due to difference in Reynolds number, were investigated numerically using solutions derived from a Reynolds Average Navier-Stokes Equations (RANS) code. The scale effect was investigated for five different propeller geometries, including straight and skewed propeller blades. A number of complex flow features were identified, resulting in changes to the propulsion performance because of dependence on Reynolds number. These dependencies are associated with viscous scaling in the vortex flow regions, with the lower Reynolds number flows having higher damping compared to higher Reynolds number flows. The latter generated stronger tip vortex flows compared to the lower Reynolds number flows. Also identified were flow separation regions, which were not identified using non-viscous Euler equation solutions. The cause of the flow separation was correlated with the complex warping of the blade surface due to principal propeller parameters of blade skew, rake, pitch, thickness and camber.
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Published date: 2002
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Local EPrints ID: 464635
URI: http://eprints.soton.ac.uk/id/eprint/464635
PURE UUID: f3f46b4e-f0d8-4eab-96c2-e8de102d707c
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Date deposited: 04 Jul 2022 23:52
Last modified: 23 Jul 2022 02:13
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Author:
Michael John Stanier
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