An Investigation on the Performance of a Pusher-Barge System in Regular Waves

Bravo, Cristobal Santiago (University of Science and Technology (UST)) | Hong, Seok Won (Korea Research Institute of Ships and Ocean Engineering (KRISO)) | Nam, Bo Woo (Korea Research Institute of Ships and Ocean Engineering (KRISO))

OnePetro 

ABSTRACT

This paper aims to investigate the performance of a pusher-barge system in regular waves. The numerical simulation is carried out through the implementation of an in-house code for the evaluation of the first-order (linear) hydrodynamic properties. For the potential flow problem around the pusher-barge system, a higher-order boundary element method (HOBEM) with wave green function in frequency domain is implemented. For the pusher-barge system, six degrees-of- freedom (6DOF) motion are evaluated and discussed for three different heading angles in deep water conditions. In this study, a pusher tug is arranged and located at the stern notch of the barge in a linear combination connected with a well-proven coupling system. The coupling system configuration for the pusher-barge system using a connection pin is considered, allowing the system to work as a single unit. The chosen connection pin system allows an independent pitch motion while roll and yaw angular motions remain coupled. Furthermore, loads on the connecting pins are calculated for different wave periods. Finally, Response Amplitude Operators (RAOs) are compared and discussed.

INTRODUCTION

A pusher-barge system is an alternative mode of sea and river transportation that is rapidly growing due to the expected development in processing, storage, and offloading facilities in deep water.

In recent years, many efforts have been made to study the significant advantages and disadvantages of the pusher-barge systems.

Compared to a towed barge configuration, the pusher-barge system offers several significant advantages including increased speed, reduced fuel consumption, ability to transit in higher sea states, access to the barge at any time, and the elimination of the vulnerable tow wire connection (Wolff, 2004). On the other hand, disadvantages are unavoidable. Severe discontinuities in the hull shape and induced turbulence at the notch area are some examples that should be considered.

So far, extensive research in model experiments has been conducted on pusher-barge systems. Valkhof et al. (2000) performed a series of experiments of a tug and barge system for sea and river services. Luo, Hu, and Zhou (2006) carried out a series of experiments where loads on the articulated connectors between a tug-barge in irregular waves were calculated. Finally, Koh and Yasukawa (2012) conducted a comparison study of a pusher-barge system in different water depth conditions where the course keeping ability of the system was evaluated.