A Simplified Fourier Method for Nonhydrostatic Mountain Waves

Abstract

A previously derived approximation to the standard Fourier integral technique for linear mountain waves is extended to include nonhydrostatic effects in a background flow with height-dependent wind and stratification. The approximation involves using ray theory to simplify the vertical eigenfunctions. The generalization to nonhydrostatic waves requires special treatment for resonant modes and caustics. Resonant modes are handled with a small amount of damping, and caustics are handled with a uniformly valid approximation involving the Airy function. This method is developed for both two- and three-dimensional flows, and its results are shown to compare well with an exact analytical result for two-dimensional mountain waves and with a numerical simulation for two- and three-dimensional mountain waves.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 2003
Accession Number
ADA525029

Entities

People

  • Dave Broutman
  • James W. Rottman
  • Stephen D. Eckermann

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Atmospheric Sciences
  • Caustics
  • Eigenvectors
  • Equations
  • Far Field
  • Flow
  • Frequency
  • Integrals
  • Layers
  • Military Research
  • Mountains
  • Phase Shift
  • Simulations
  • Standards
  • Stratified Fluids
  • Three Dimensional
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Calculus or Mathematical Analysis
  • Wave Propagation and Nonlinear Chaotic Dynamics.