# Accession Number:

## ADA277582

# Title:

## A Rapid-Pressure Correlation Representation Consistent with the Taylor-Proudman Theorem Materially-Frame-Indifferent in the 2D Limit

# Descriptive Note:

## Contractor rept.

# Corporate Author:

## INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA

# Personal Author(s):

# Report Date:

## 1994-01-01

# Pagination or Media Count:

## 51.0

# Abstract:

A nonlinear representation for the rapid-pressure correlation appearing in the Reynolds stress equations, consistent with the Taylor-Proudman theorem, is presented. The representation insures that the modeled second-order equations are frame-invariant with respect to rotation when the flow is two- dimensional in planes perpendicular to the axis of rotation. The representation satisfies realizability in a new way a special ansatz is used to obtain, analytically, the values of coefficients valid away from the realizability limit the model coefficients are functions of the state of the turbulence that are valid for all states of the mechanical turbulence attaining their constant limiting values only when the limit state is achieved. Utilization of all the mathematical constraints are not enough to specify all the coefficients in the model. The unspecified coefficients appear as free parameters which are used to insure that the representation is asymptotically consistent with the known equilibrium states of a homogeneous sheared turbulence. This is done by insuring that the modeled evolution equations have the same fixed points as those obtained from computer and laboratory experiments for the homogeneous shear. Results of computations of the homogeneous shear, with and without rotation, and with stabilizing and destabilizing curvature, are shown. Results are consistently better, in a wide class of flows which the model not been calibrated, than those obtained with other nonlinear models. Turbulence modeling, Rapid pressure.

# Descriptors:

# Subject Categories:

- Numerical Mathematics
- Fluid Mechanics