Investigation of the Constant of Surface Roughness Function.

Hanna, Samir F.; Djebedjian, Berge Ohaness

doi:10.21608/bfemu.2021.176997

Investigation of the Constant of Surface Roughness Function.

Document Type : Research Studies

Authors

¹ Electrical Power Engineering Department., Faculty of Engineering., El-Mansoura University., Mansoura., Egypt.

² Mechanical Power Engineering Department., Faculty of Engineering., El-Mansoura University., El-Mansoura 35516., Egypt.

10.21608/bfemu.2021.176997

Abstract

The main objective of this paper is to throw some light on the constant of surface roughness function. Many investigators related that constant to the surface roughness density defined as the ratio of the total surface area is the roughness area. Others introduced alternative definition, to be the ratio of the total surface area to the total roughness frontal area normal to the flow.
The influence of pressure gradient is not considered by those investigators. Moreover, they suggested a unique value for this constant in the presence of pressure gradient.
In this research, the analytical study of the constant of surface roughness function regarding the pressure gradient in form of Euler number. shows variable values for different ratios of k / ẟ٭٭.

Main Subjects