Faculty Publications

The Influence Of Topography And Approach Angles On Local Deflections Of Airflow Within A Coastal Blowout

Document Type

Article

Keywords

Aeolian transport, Blowout, Coastal dune, Turbulence, Wind vane

Journal/Book/Conference Title

Earth Surface Processes and Landforms

Volume

38

Issue

10

First Page

1160

Last Page

1169

Abstract

The spatial variability of air flow through complex topography is an important, but not fully understood, component of dune development and dynamics. This study examines the spatial variability of the wind field in a linear blowout in coastal dunes at Jockey's Ridge State Park, on the Outer Banks of North Carolina. A spatial array of single-height anemometers and wind vanes were placed within the blowout. Topography exerted a significant steering effect when onshore winds approached from directions within 50° of the blowout axis. Under those conditions wind flow in the blowout aligned to the axis regardless of approach angle, maximizing the potential for erosion and transport in the trough. In other locations aspect variations caused deflection both proportional and disproportional to changes in the approaching wind. When prevailing winds approached from directions more oblique than 50° to the blowout axis, topographic steering through the blowout trough was reduced and secondary flow generated by flow separation over the trough became more prominent. During those approach angles, wind directions and speeds within the upper blowout trough became erratic as vortices and turbulence dominated the flow, minimizing transport potential. The changing characteristics of airflow in the blowout relative to differing approach angles has implications on dune development and variations in transport potential under changing conditions. © 2013 John Wiley & Sons, Ltd.

Department

Department of Geography

Original Publication Date

8-1-2013

DOI of published version

10.1002/esp.3407

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