Session: 06-05-04 Marine Hydrodynamics IV

Paper Number: 81026

81026 - Hydrodynamic Analysis of a Triple Thruster Unit Via a BEM/RANS Interactive Method 

In this paper, a boundary element method (BEM) is used to predict the unsteady performance of ducted propellers in open water and ship behind conditions. To improve the accuracy of a potential flow solver for highly viscous problems, such as separated flow near a blunt body, the section profiles of the duct are modified from a blunt trailing edge duct to a sharp trailing edge duct. The present method modifies the duct profiles based on the predicted streamlines from an interactive scheme, which couples a potential flow solver, applied on the propeller, with a viscous flow Reynolds-Averaged Navier-Stokes (RANS) solver, applied on the duct. Then, the effective wake to the propeller blades is predicted in ship behind conditions, via an iterative method which couples the BEM applied on the ducted propeller, with a viscous flow solver which solves for the flow around the hull/rudder/duct, to account for the viscous interactions between the non-axisymmetric hull/rudder and the ducted propeller. The effective wakes are predicted under different configurations of the hull/propeller geometry and various operating conditions to investigate how the flow field is influenced by the hull/propeller/rudder interactions. The predicted open water performance and unsteady forces are compared with experimental measurements and results from unsteady RANS simulations over a range of loading conditions. Comparisons are also made between the predicted effective wakes in the cases of ducted propellers or open propellers, in order to investigate how the flow field is affected by the existence of the duct.

Presenting Author: Seungnam Kim Ocean Engineering Group, CAEE, The University of Texas at Austin

Authors:

Seungnam Kim Ocean Engineering Group, CAEE, The University of Texas at Austin
Spyros A. Kinnas Ocean Engineering Group, CAEE, The University of Texas at Austin
Jahn Terje Johannessen BRUNVOLL
Ray Thomas Grebstad BRUNVOLL