Session: 08-01-02 Maneuvering Simulation

Paper Number: 127881

127881 - Cfd Simulation of Hydrodynamic Interaction Between Ship and a Podded Propeller Using Body Force Method 

This study presents an application example of the body force method to simulate podded propeller configurations in ship design. Computational Fluid Dynamics (CFD) simulation has become an essential tool in ship design, extending beyond typical calm water resistance to more complex scenarios, such as maneuvering simulation in waves. For more realistic simulations, a self-propelled ship model is required by taking account of the hydrodynamic interaction between a ship and its propulsion unit. However, implementing a rotating propeller in CFD simulation requires substantial computational resources. Therefore, the body force method, a simplified numerical approach by distributing source terms to mimic propeller-induced flow, is widely used for its computational efficiency.
While the body force method offers computational advantages, it has limitations on unsteady flow characteristics in propeller flows. The propeller wake, as simulated by the body force method, is normalized by the rotating distance and also time-averaged, which could impact on the simulation outcomes. Where there is a strong hydrodynamic interaction with adjacent structures such as a nozzle and pod, the normalized flow pattern can lead to unreliable results by simplifying the unsteady and non-uniform flow characteristics in real propeller wake .
In this paper, we conduct a comparative study for a podded propeller. The open water performance of a podded propeller unit is estimated through two approaches: the body force method and the rotating propeller simulation. Simulation outcomes from both approaches are compared, especially focusing on the effect from advance ratio and pressure distribution on the pod surface. In addition to the open water performance, a case study of a propeller overload test is carried out considering the hydrodynamic interaction between a hull and a pod unit.  This study aims to identify potential risks under non-uniform inflow condition associated with adopting the body force method, such as inaccurate propeller thrust or biased lift force on the pod. 
 

Presenting Author: Fatima Jahra National Research Council Canada

Presenting Author Biography: She is a research council officer in NRC Ocean, Coastal and River Engineering Research Center. She obtained Master Degree in Environmental Engineering and Doctorate Degree in Civil and Environmental Engineering. She has been working in a research/engineering position since 2004 and is interested in numerical simulations for hydrodynamic performance of ship and marine structure. Also she is experienced in design of experiments for model testing and engineering process.

Authors:

Dong Cheol Seo National Research Council Canada
Fatima Jahra National Research Council Canada
Jungyong Wang National Research Council Canada