# Accession Number:

## ADA300184

# Title:

## A Particle-in-Cell Model for Geophysical Fluid Flows.

# Descriptive Note:

## Final rept.,

# Corporate Author:

## OLD DOMINION UNIV NORFOLK VA

# Personal Author(s):

# Report Date:

## 1995-01-01

# Pagination or Media Count:

## 48.0

# Abstract:

A particle in cell ansatz for solving the Euler equations for geophysical fluid dynamics is described. The approach is ideally suited for layered models in which density and velocity are independent of the vertical coordinate in fluid layers but generally vary with layer specification. The material acceleration terms in the Euler equations are solved at each particle while the gradient terms are evaluated on a grid and interpolated at each time step to the particles. Particles are given a specified tetrahedral shape whose base area is equal to four computational cells however, there are many particles in each cell. The height of each particle is fixed and may be constant for all particles or may vary from particle to particle. In either case criteria are established for the number of particles required for each layer. The efficacy of the model is illustrated by comparing solutions with those from an exact solution of a nonlinear reduced gravity model of a parabolic lens. The particle in cell model reproduces the essential characteristics of the reduced gravity model including exceptional resolution of the time varying surface front of the lens.

# Descriptors:

# Subject Categories:

- Physical and Dynamic Oceanography
- Fluid Mechanics