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Numerical Modeling Studies of Wake Vortex Transport and Evolution Within the Planetary Boundary LayerIn support of the wake vortex effect of the Terminal Area Productivity program, we have put forward four tasks to be accomplished in our proposal. The first task is validation of two-dimensional wake vortex-turbulence interaction. The second task is investigation of three-dimensional interaction between wake vortices and atmospheric boundary layer (ABL) turbulence. The third task is ABL studies. The, fourth task is addition of a Klemp-Durran condition at the top boundary for TASS model. The accomplishment of these tasks will increase our understanding of the dynamics of wake vortex and improve forecasting systems responsible for air safety and efficiency. The first two tasks include following three parts: (a) Determine significant length scale for vortex decay and transport, especially the length scales associated with the onset of Crow instability (Crow, 1970); (b) Study the effects of atmospheric turbulence on the decay of the wake vortices; and (c) Determine the relationships between decay rate, transport properties and atmospheric parameters based on large eddy simulation (LES) results and the observational data. These parameters may include turbulence kinetic energy, dissipation rate, wind shear and atmospheric stratification. The ABL studies cover LES modeling of turbulence structure within planetary boundary layer under transition and stable stratification conditions. Evidences have shown that the turbulence in the stable boundary layer can be highly intermittent and the length scales of eddies are very small compared to those in convective case. We proposed to develop a nesting grid mesh scheme and a modified Klemp-Durran conditions (Klemp and Wilhelmson, 1978) at the top boundary for TASS model to simulate planetary boundary layer under stable stratification conditions. During the past year, our group has made great efforts to carry out the above mentioned four tasks simultaneously. The work accomplished in the last year will be described in the next section.
Document ID
19980048378
Acquisition Source
Langley Research Center
Document Type
Contractor Report (CR)
Authors
Lin, Yuh-Lang (North Carolina State Univ. Raleigh, NC United States)
Arya, S. Pal (North Carolina State Univ. Raleigh, NC United States)
Kaplan, Michael L. (North Carolina State Univ. Raleigh, NC United States)
Shen, Shaohua (North Carolina State Univ. Raleigh, NC United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1998
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
NAS 1.26:207826
NASA/CR-1998-207826
Funding Number(s)
CONTRACT_GRANT: NCC1-188
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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