Tuesday, 31 July 2001: 4:30 PM
Stratified flows past 3D ridges at intermediate Rossby number
The flow of a stratified fluid past three-dimensional (3D) obstacles
at intermediate Rossby number (Ro approximately unity) is studied
using linear semi-analytic calculations and nonlinear numerical
simulations. Linear solutions are obtained using a Fourier transform
approach combined with a recently developed methodology for computing
accurate numerical approximations to the singular Fourier inversion
integrals. Using this technique, the change in the linear flow
patterns is explored as the Rossby number is gradually decreased from
roughly Ro=10 (essentially nonrotating flow) to Ro=0.1 (essentially
quasi-geostrophic flow). This regime of intermediate-Rossby-number
disturbances has previously received little attention in the case of
3D flows. The linear solutions are then compared to nonlinear
numerical simulations at finite obstacle height in an effort to identify
important nonlinear effects.
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