Theses and Dissertations

Issuing Body

Mississippi State University


Hodge, B. K.

Committee Member

Chamra, Louay

Committee Member

Steele, W. G.

Date of Degree


Document Type

Graduate Thesis - Open Access


Mechanical Engineering

Degree Name

Master of Science (M.S.)


James Worth Bagley College of Engineering


Department of Mechanical Engineering


A computer program based on the discrete-element method has been developed to compute friction factors and Nusselt Numbers for fully-developed turbulent flows with randomly-rough surfaces. Formulations of the discrete-element model for fully-developed turbulent flows inside circular pipes and between infinite parallel plates with the necessary adaptations for randomly-rough surfaces are provided. Utilizing the output of a three-dimensional profilometer, proper description of the randomly-rough surface is necessary for use within the discrete-element model. Proper description of the randomly-rough surface is achieved by the McClain (2002) method of characterization. Predictions from the discrete-element model computer program are compared with the classical, laminar and turbulent, smooth-wall results. In addition to the smooth-wall evaluations, predictions are compared with experimental results for turbulent internal flows with deterministic surface roughness. Predictions from the model demonstrated excellent agreement in all cases. Friction factor and Nusselt Number predictions for fully-developed flows over randomly-rough surfaces are also presented. With the friction factor and Nusselt Number data, velocity profiles for flows over randomly-rough, deterministically-rough and smooth surfaces are provided for comparison.