Accession Number:

ADP004787

Title:

A Discrete Element Prediction Approach for Turbulent Flow Over Rough Surfaces,

Descriptive Note:

Corporate Author:

MISSISSIPPI STATE UNIV MISSISSIPPI STATE

Personal Author(s):

• Taylor,R. P.
• Coleman,H. W.
• Hodge,B. K.

Report Date:

1984-08-01

Pagination or Media Count:

12.0

Abstract:

A discrete element model for turbulent flow over rough surfaces has been rigorously derived from basic principles. This model includes surface roughness effects as a constitutent part of the partial differential equations which describe momentum and energy transport in turbulent flows. The model includes the necessary empirical information on the interaction between the roughness elements and the flow around and between the elements in a general way which does not require experimental data on each specific surface. This empirical information is input via algebraic models for the local element drag coefficient and Nusselt number. These models were calibrated by comparison with base data sets from surfaces with three-dimensional distributed roughness elements. Calculations using the present model have been compared with experimental data from 118 separate experimental runs. The results of these comparisons ranged from good to excellent. The calculations compared equally well with both transitionally rough and fully rough turbulent flow results without modification of the roughness model. Author

Descriptors:

• *GAS FLOW
• *TURBULENT FLOW
• *MATHEMATICAL MODELS
• SURFACE ROUGHNESS
• MATHEMATICAL PREDICTION
• CALIBRATION
• EXPERIMENTAL DATA

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE