# Accession Number:

## ADA030802

# Title:

## Limit Modeling of Thermal Turbulence in Unstably Stratified Flows

# Descriptive Note:

## Technical rept.

# Corporate Author:

## BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING

# Personal Author(s):

# Report Date:

## 1976-07-04

# Pagination or Media Count:

## 44.0

# Abstract:

A new, relatively simple, rational, and viable theory of phenomenological thermal turbulence occurring in incident unstably stratified fluid flows is discussed. The subject of stratified flow has consisted largely of the study of stably stratified incident flows and of unstable thermal convection of a fluid heated from below with no incident flow. The new turbulence theory is intermediate in complexity between the turbulent eddy- transport theory and the very complex generic theory known as turbulence modeling. The method is called a limit theory of phenomenological thermal turbulence modeling based on a system of plausibly large and small parameters, it is more suitable in many applications where the said parameters behave as required moreover, the theory lends itself to systematic improvement. The research consists of a study of turbulent cellular flow due to an unstable temperature stratification underneath a flow with a stable temperature stratification. These two layers are separated by an interface whose detailed structure is a pausal boundary layer. The turbulent thermal convection below buffets the upper layer by means of penetrative convection and heats the upper layer at the interface because the turbulent heat flux mechanism must switch off. The penetrative convection and heat switch must amount to a heat engine whereby the rate of work of thermal origin is done on the bottom of the upper layer. This power source can then produce internal, surface, and Kelvin- Helmholtz waves.

# Descriptors:

# Subject Categories:

- Atmospheric Physics
- Physical and Dynamic Oceanography
- Numerical Mathematics
- Fluid Mechanics