Page 454 - Practical Design Ships and Floating Structures

Practical Design of Ships and Other Floating Structures 429
You-Sheng Wu, Wei-Cheng Cui and Guo-Jun Zhou (Eds)
0 2001 Elsevier Science Ltd. All rights reserved

NUMERICAL SIMULATION OF FLOWS OVER UNDERWATER
AXISYMMETRIC BODIES WITH FULL APPENDAGES

Zhen-Yu Huang and Lian-Di Zhou
China Ship Scientific Research Center, Wuxi 214082, China

ABSTRACT

The numerical method based on flux-difference splitting LU decomposition, implicit high-resolution
third-order Essentially Non-Oscillatory (ENO) schemes is constructed for efficient computations of
steady-state solution to the threedimensional, incompressible Navier-Stokes equations in curvilinear
coordinates. The flowfields over underwater misymmetric bodies with a fairwater and four stem
appendages are calculated.
The numerical results show that the circumferential-mean nondimensional velocity profiles at propeller
are in good agreement with the experimental data, which can satisfied with the need of wake profile
accuracy in the design of propuslor blade. Meanwhile the circumferential distributions of numerical non-
dimensional velocity at the propeller plane are also similar with the experimental data, which can be
used to predict the water noise generated by vehicle propulsor.

KEYWORDS
Essentially Non-Oscillatory (ENO) Schemes, Flux Splitting, LU Decomposition, Computational Fluid
Dynamics (CFD)

1 INTRODUCTION

The flow over an appended body during level flight is characterized by thick boundary layers, vortical
flow structure generated by hulvappendage junctures, and appendage turbulent wakes. The spatial
nonuniformity and temporal fluctuations of the flow into propulsor significantly affect propulsor noise.
For a long period the model experiment is the main way to get data for the flow field over an appended
body, but are still limited. CFD numerical methods for the design of submarines and other ships are
successfully applied in shipbuilding industry, which can shorten the time needed in the ship design and
save lots of research fund. The goal of this paper is to present a CFD numerical method which can be
used to study the flow field over underwater bodies with a fairwater and four stem appendages.
The schemes based on flux-difference splitting, implicit high-resolution are constructed for computations
of steady-state solutions to the threedimensional, incompressible conservative Navier-Stokes equations
in curvilinear coordinate. These schemes use third-order-accurate Essentially Non-Oscillatory(EN0)
differencing for inviscid flux and second-order central differencing for the viscous shear flux. Up to
third-order-accurate Essentially Non-Oscillatory(EN0) differencing is achieved through flux