Assessing the frictional and baroclinic contributions to stratified wake formation: a parameter space study
The baroclinic and surface-frictional contributions to stratified wake formation are considered as a function of the non-dimensional height ( = Nho/U) and aspect-ratio ( = ho/L) of the barrier. Numerical simulations are computed for a wide range of the - parameter space, including both unstratified ( = 0) and highly stratified ( = 4) flows and for terrain slopes characteristic of both geophysical ( = 0.1) and laboratory scale ( = 2.0) obstacles. Simulations both with and without applied surface stresses are compared to gain insight into the baroclinic and surface-frictional contributions to each flow. Particular emphasis is given to the changes in kinematic wake structure, the relative contributions of skin and pressure drag, and the vertical momentum flux observed as the mountain height and terrain slope are varied. We also examine several cases from the parameter-space study in more detail using a method for decomposing the flow into baroclinic and viscous parts. The decompositions show that for large- and small- flows, wake generation is primarily baroclinic in nature, while at smaller- and/or larger-, the wake becomes increasingly surface frictional.
Advisor:Epifanio, Craig C.; Hetland, Robert; Nielsen-Gammon, John; Zhang, Fuqing
School:Texas A&M University
School Location:USA - Texas
Source Type:Master's Thesis
Keywords:baroclinic frictional orographic wake vortex stratified epifanio smith
Date of Publication:05/01/2005