CFD Simulation on Workability of a Seaweed Harvesting Boat Due to Wake-Wash

Marco Polo Espinoza Haro,Dong-Hyun Kim,Jong-Chun Park,Sung-Bum Lee

doi:10.3390/jmse8080544

Abstract

In the present study, a 2-ton class seaweed harvesting boat was optimized by employing a W-shape hull form to reduce roll motion due to wake-wash from passing boats. A series of numerical simulations were conducted using Star-CCM+, a commercial CFD (computational fluid dynamics) software, to improve workability by optimizing the hull form from the conventional design (original hull form). The 2-dimensional roll decay motion of various hull forms with W-shape midsection were simulated and the hull form with the best performance in free roll decay test was selected. To evaluate stability of each hull in wake-wash, the original or optimized hull was alternately located at the middle of a computational domain as a target ship while an advancing ship (original hull) moved forward generating Kelvin waves which impact the original or optimized boat. Two kinds of working conditions, i.e., ballast and full loading conditions, of the target ship were considered with and without initial roll angle. It was observed through the comparison of motion between the original and optimized hulls a decrement of roll motion for the optimized ship demonstrating the effectiveness of the W-shape hull. Decrement of roll motion was observed for both working conditions. Additionally, the optimized W-shape hull showed an extraordinary performance under the ballast condition without initial roll angle.

Highlights

Seaweed has been used across the world for centuries in coastal communities but in many industries such as pharmaceuticals, industrial sectors, and food industry due to its rich nutritional composition [1]
4t.hCe orenTschuleultssniouofnmmsereinctailonmeedthnoudmeursiecdal schemes were validated with experimental results in the validation case was used to simulate the
The numerical method used in the validation case was used to simulate the roll motion of 11 modified hulls based on a 2-D model

Summary

Introduction

Seaweed has been used across the world for centuries in coastal communities but in many industries such as pharmaceuticals, industrial sectors (soil fertilizers), and food industry due to its rich nutritional composition [1]. Seaweed can be harvested in farms or from the wild by hand from open boats. Harvesting seaweed by hand is a dangerous activity because workers are biased toward one side in the ship producing a change in the center of gravity generating a heel angle. Ship traffic of advancing ships near seaweed farms could induce a large energy affecting the stability of the harvesting boats. The far-fields generated by advancing ships are classified in transverse and divergent waves [2]; while transverse waves might not impact the harvesting boats’ stability, divergent waves might increase the energy at the seaweed farm. Divergent waves produced by nearby ships, so-called ‘wake-wash’, can increase the heel angle leading to a risky situation for the operational personnel [3]

Objectives

Methods

Conclusion