Parametric design and simulation of asymmetric stern for containership
Journal
Journal of Taiwan Society of Naval Architects and Marine Engineers
Journal Volume
35
Journal Issue
1
Pages
9-20
Date Issued
2016
Author(s)
Abstract
The propulsive efficiency of containerships usually is related to the tangential momentum loss in the wake zone behind the propeller. An asymmetric stern is an example to elevate the efficiency practically by pre-rotating the flow field in front of the propeller. In the presented study, a parametric transformation model applied to stern lines was constructed. The transformation includes three parameters: twisting strength, longitudinal distribution and radial distribution, to transform an arbitrary symmetric hull form into an asymmetric one while keeping the surface smoothness. The tested model in this study was the containership published by KRISO along with its propeller. The CFD tool STAR-CCM+ was used to simulate the resistance and propulsion tests, and then compare the result with the experimental data for validation. In addition to the nominal wake fraction, which solely accounts for the axial velocity, the tangential velocity distribution was evaluated. To discuss the relation between the transformation parameters and the axial/tangential velocity distribution in the wake zone, we studied 25 versions of asymmetric sterns and found the best parameter combination that achieved the optimal tangential velocity distribution. For the propulsion simulations, the delivered horse power can be reduced by 0.8% at the same propeller load.
Subjects
Computational fluid dynamics
Containers
Efficiency
Fuel tanks
Propellers
Propulsion
Velocity
Wakes
Asymmetric stern
Longitudinal distribution
Parameter combination
Parametric design
Parametric transformation
Propulsion simulation
Propulsive efficiencies
Transformation parameters
Velocity distribution
Type
journal article