• Cermak, J. E., , and Horn J. D. , 1968: Tower shadow effect. J. Geophys. Res., 73 , 18691876.

  • Ching, J. K. S., 1976: Ship’s influence on wind measurements determined from BOMEX mast and boom data. J. Appl. Meteor., 15 , 102106.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dabberdt, W. F., 1968a: Tower induced errors in wind profile measurements. J. Appl. Meteor., 7 , 359366.

  • Dabberdt, W. F., 1968b: Wind disturbance by a vertical cylinder in the atmospheric boundary layer. J. Appl. Meteor., 7 , 367371.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dobson, F. W., 1981: Review of reference height for and averaging time of surface wind measurements at sea. Marine Meteorology and Related Oceanographic Activities Rep. 3, WMO, Geneva, Switzerland, 64 pp. [Available from World Meteorological Organization, Case Postale 5, CH-1211 Geneva 20, Switzerland.].

  • Dupuis, H., , Guerin C. , , Hauser D. , , Weill A. , , Nacass P. , , Drennan W. M. , , Cloche S. , , and Graber H. C. , 2003: Impact of flow distortion corrections on turbulent fluxes estimated by the inertial dissipation method during the FETCH experiment on R/V L’Atalante. J. Geophys. Res., 108 .8064, doi:10.1029/2001JC001075.

    • Search Google Scholar
    • Export Citation
  • Gill, G. C., , Olsson L. E. , , Sela J. S. , , and Suda M. , 1967: Accuracy of wind measurements on towers and stacks. Bull. Amer. Meteor. Soc., 48 , 665674.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hunt, J. C. R., , Abell C. J. , , Peterka J. A. , , and Woo H. , 1978: Kinematical studies of the flows around free or surface-mounted obstacles; applying topology to flow visualisation. J. Fluid Mech., 86 , 179200.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kahma, K. K., , and Leppäranta M. , 1981: On errors in wind speed observations on R/V Aranda. Geophysica, 17 , 155165.

  • Kent, E. C., , and Taylor P. K. , 1991: Ships observing marine climate: A catalogue of the voluntary observing ships participating in the VOSP-NA. Marine Meteorology and Related Oceanographic Activities Rep. 25 , World Meteorological Organization, 123 pp.

  • Moat, B. I., , Molland A. F. , , and Yelland M. J. , 2004: A wind tunnel study of the mean airflow around a simple representation of a merchant ship. SOC Research and Consultancy Rep. 87, Southampton Oceanography Centre, Southampton, United Kingdom, 21 pp. [Available from National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom.].

  • Moat, B. I., , Yelland M. J. , , Pascal R. W. , , and Molland A. F. , 2005: An overview of the airflow distortion at anemometer sites on ships. Int. J. Climatol., 25 , 9971006.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Moat, B. I., , Yelland M. J. , , Pascal R. W. , , and Molland A. F. , 2006: Quantifying the airflow distortion on merchant ships. Part I: Validation of a CFD model. J. Atmos. Oceanic Technol., 23 , 341350.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Murakami, S., , Mochida A. , , and Hayashi Y. , 1993: Comparison of various turbulence models applied to a bluff body. J. Wind Eng. Indust. Aerodyn., 46/47 , 2136.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Popinet, S., , Smith M. , , and Stevens C. , 2004: Experimental and numerical study of the turbulence characteristics of airflow around a research vessel. J. Atmos. Oceanic Technol., 21 , 15751589.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ricardo, 2001: VECTIS computational fluid dynamics (release 3.5). Ricardo Consulting Engineers Ltd., Shoreham-by-Sea, United Kingdom, 262 pp. [Available from Ricardo Consulting Engineers Ltd., Bridge Works, Shoreham-by-Sea, West Sussex BN43 5FG, United Kingdom.].

  • RINA, 1990–1993: Significant ships. The Royal Institution of Naval Architects, London, United Kingdom.

  • WMO, 1994: International list of selected, supplementary and auxiliary ships. WMO Rep. 47, Geneva, Switzerland.

  • Yelland, M. J., , Moat B. I. , , Taylor P. K. , , Pascal R. W. , , Hutchings J. , , and Cornell V. C. , 1998: Wind stress measurements from the open ocean corrected for airflow distortion by the ship. J. Phys. Oceanogr., 28 , 15111526.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yelland, M. J., , Moat B. I. , , Pascal R. W. , , and Berry D. I. , 2002: CFD model estimates of the airflow over research ships and the impact on momentum flux measurements. J. Atmos. Oceanic Technol., 19 , 14771499.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 61 61 8
PDF Downloads 36 36 6

Quantifying the Airflow Distortion over Merchant Ships. Part II: Application of the Model Results

View More View Less
  • 1 National Oceanography Centre, Southampton, United Kingdom
  • | 2 School of Engineering Sciences, Ship Science, University of Southampton, Southampton, United Kingdom
© Get Permissions Rent on DeepDyve
Restricted access

Abstract

Wind speed measurements obtained from ship-mounted anemometers are biased by the presence of the ship, which distorts the airflow to the anemometer. Previous studies have simulated the flow over detailed models of individual research ships in order to quantify the effect of flow distortion at well-exposed anemometers, usually sited on a mast in the ship's bows. In contrast, little work has been undertaken to examine the effects of flow distortion at anemometers sited on other merchant ships participating in the voluntary observing ship (VOS) project. Anemometers are usually sited on a mast above the bridge of VOS where the effects of flow distortion may be severe. The several thousand VOS vary a great deal in shape and size and it would be impractical to study each individual ship.

This study examines the airflow above the bridge of a typical, or generic, tanker/bulk carrier/general cargo ship using computational fluid dynamics models. The results show that the airflow separates at the upwind leading edge of the bridge and a region of severely decelerated flow exists close to the bridge top with a region of accelerated flow above. Large velocity gradients occur between the two regions.

The wind speed bias is highly dependent upon the anemometer location and varies from accelerations of 10% or more to decelerations of 100%. The wind speed bias at particular locations also varies with the relative wind direction, that is, the angle of the ship to the wind. Wind speed biases for various anemometer positions are given for bow-on and beam-on flows.

Corresponding author address: Dr. B. I. Moat, National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom. Email: bim@noc.soton.ac.uk

Abstract

Wind speed measurements obtained from ship-mounted anemometers are biased by the presence of the ship, which distorts the airflow to the anemometer. Previous studies have simulated the flow over detailed models of individual research ships in order to quantify the effect of flow distortion at well-exposed anemometers, usually sited on a mast in the ship's bows. In contrast, little work has been undertaken to examine the effects of flow distortion at anemometers sited on other merchant ships participating in the voluntary observing ship (VOS) project. Anemometers are usually sited on a mast above the bridge of VOS where the effects of flow distortion may be severe. The several thousand VOS vary a great deal in shape and size and it would be impractical to study each individual ship.

This study examines the airflow above the bridge of a typical, or generic, tanker/bulk carrier/general cargo ship using computational fluid dynamics models. The results show that the airflow separates at the upwind leading edge of the bridge and a region of severely decelerated flow exists close to the bridge top with a region of accelerated flow above. Large velocity gradients occur between the two regions.

The wind speed bias is highly dependent upon the anemometer location and varies from accelerations of 10% or more to decelerations of 100%. The wind speed bias at particular locations also varies with the relative wind direction, that is, the angle of the ship to the wind. Wind speed biases for various anemometer positions are given for bow-on and beam-on flows.

Corresponding author address: Dr. B. I. Moat, National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom. Email: bim@noc.soton.ac.uk

Save