Dynamically Driven Roll Circulations in an Inversion-Capped Boundary Layer
Abstract
From a Boussinesq system of equations modified to include background wind and temperature profiles, a two-dimensional, nonlinear spectral model is derived to study the development of boundary layer roll circulations in a nonrotating, stratified environment. The spectral expansions for the dependent variables include more than one vertical harmonic, thereby allowing the determination of the structure of the roll circulations and the roles of the dynamic and thermodynamic instability mechanisms. The dynamic forcing is represented by a Fourier expansion of an arbitrary vertical profile of the background horizontal wind. In this theses, only the linear aspects of the roll solutions are examined through the use of a standard linear stability analysis. From this analysis are obtained the minimum critical values of the dynamic forcing parameter Re and the effective thermodynamic forcing parameter Ra sub e that represent the smallest magnitudes of the forcing rates required for the onset of roll circulations. In addition, the preferred horizontal wavelengths, circulation depths and orientations with respect to a reference direction are found for the various roll modes. (JHD)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1989
- Accession Number
- ADA228918
Entities
People
- Robert Medred
Organizations
- Air Force Institute of Technology