Accession Number:

AD0777429

Title:

Using Helicopters to Clear Fog: A Numerical Study

Descriptive Note:

Corporate Author:

NAVAL ENVIRONMENTAL PREDICTION RESEARCH FACILITY MONTEREY CA

Personal Author(s):

• Johnson, David B.
• Barker, Edward H.
• Lowe, Paul R.

Report Date:

1974-03-01

Pagination or Media Count:

45.0

Abstract:

A two-dimensional axial symmetric cloud dynamics model, which uses the Boussinesq approximation form of the equations of motion, was used to study downwash-induced fog clearings. The flow produced by constraining the vorticity to a prescribed value in a small region near the centerline of the model is similar to that observed to occur below a hovering helicopter. Several numerical experiments are discussed which show the efficacy of different hovering altitudes on the clearing of fog. The major feature affecting the size of clearing by helicopter downwash is the size of the primary downwash volume.

Descriptors:

• *HELICOPTERS
• *WEATHER MODIFICATION
• DISPERSING
• DOWNWASH
• FOG
• HOVERING
• MATHEMATICAL MODELS
• WAKE

Subject Categories:

• Helicopters
• Meteorology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE