Accession Number:

ADA031876

Title:

A Finite Element Prediction Model with Variable Element Sizes

Descriptive Note:

Master's thesis

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

1976-09-01

Pagination or Media Count:

107.0

Abstract:

There are a variety of meteorological forecast problems which require high spatial resolution in only a limited area. An important example of this type of problem is the prediction of tropical cyclones. This study tests a simple finite element prediction model with a variable element size. The shallow water equations are used and the motion is confined in a periodic channel on a f-plane. The Galerkin technique is applied to linear basis functions on triangular elements. The model uses leapfrog time differencing and periodic restarts. The model is tested with a wave imbedded in a mean flow and also with an isolated vortex. The experiments with a uniform element size show excellent phase propagation, but some small scale noise is generated. The introduction of momentum diffusion terms helps to control the noise. The model is also tested with elements which decrease abruptly in scale along a line and with elements which decrease smoothly. Both of these cases generate more noise than with uniform elements.

Subject Categories:

  • Meteorology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE