High-Resolution Analysis of Wind Flow Behavior on Ship Stacks Configuration: A Portuguese Case Study

Luís P Correia,Sandra Rafael,Carlos Borrego,Vera Rodrigues,Alexandra Monteiro,Sandra Sorte

doi:10.3390/atmos12030303

Luís P Correia, Sandra Rafael + Show 4 more

Open Access

https://doi.org/10.3390/atmos12030303

Copy DOI

Journal: Atmosphere	Publication Date: Feb 26, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: University of Aveiro

Abstract

Atmospheric emissions related to harbor-related activities can significantly contribute to air pollution of coastal urban areas and so, could have implications to the citizens’ health that live in those areas. Of great concern is the local impact of the emissions that are generated while ships are at berth, since not all types of ships switch off the main engines. This paper intends to investigate the influence of the stack configuration for generic cargo ships on the exhaust smoke dispersion, using the Port of Leixões as a case study and a series of wind tunnel experiments with support of Particle Image Velocimetry (PIV) technique. For that, different configurations of the stack of a cargo ship (in terms of height, geometry and diameter) were simulated under the typical wind conditions of the study area. The PIV results indicate negligible differences between the medium and long stack height, with the short stack height presenting a strong impact on the flow field around the stack. For the short stack height, the flow field is not only disturbed by the stack, but also by the cargo ship bridge, with both obstacles promoting disturbances on the flow field and creating a large wake turbulence effect, which is important for the downwash phenomena. Regarding the effects linked with two distinct geometries (straight or curved), the results show that the straight chimney led to higher perturbation of wind field when compared with the curved geometry. The curved stack presents an increase of vorticity, indicating the generation of more turbulent structures. The PIV results also confirmed that higher wind velocity at the inlet conducts to higher vorticity levels, as well as a higher number of Kelvin–Helmholtz structures. For distinct wind conditions the PIV measurements point out different patterns, indicating the northern wind direction as the most favorable condition for the exposure of dock workers to pollutants. Overall, the results showed that a ship stack with a curved end, medium length and smaller diameter has the capability to promote the behaviors in the flow that are coherent with increased pollutant dispersion.

Highlights

Introduction published maps and institutional affilThe increase of international trade and tourism boosted the growth of maritime transport though the last decade [1], which makes harbors key contributors to social and economic development worldwide [2]
The wind tunnel experiments were conducted for the selected is their curvature: instead of using straight stacks, a curved geometry will promote an typical wind conditions over the Leixões study area, i.e., wind blowing from increased vorticity and increase the dispersion of exhaust pollutants from ships
These wind conditions were selected and Northeast, with typical ofa1–2 m. s−end, With these results in mind, a shipvelocities stack with curved medium length and smaller nothas onlythe based on the representativeness of the meteorological conditions of the with study area, diameter capability to promote the behaviors in the flow that are coherent and considering the influence of the surrounding areas on the wind flow field patterns

Summary

Introduction

The increase of international trade and tourism boosted the growth of maritime transport though the last decade [1], which makes harbors key contributors to social and economic development worldwide [2]. There is a rising concern about the impact of maritime transport and its related activities (maneuvering ships to the activity at the dock and at berthing ship) on local air quality, with a set of studies pointed out that emissions from ships may have a strong impact on human health in coastal communities [3]. Due to the increasing demand for larger, faster and more sophisticated ships, it was required to impose stricter design standards for the exhaust stack of ships and these were introduced in 2005 by the Marine Pollution Convention (MARPOL) Annex VI by the International Maritime Organization (IMO) to control both air pollution and heat damage problems [4]. The contamination from smoke discharged from the funnels of ships has been found to manifest itself in the form of objectionable quantities of smoke coming down iations.

Methods

Results

Conclusion