Law of Velocity Distribution for Turbulent Boundary Layer with Adverse Pressure Gradient over Rough Surface.

Hanna, Samir Francis; Djebedjian, Berge Ohaness

doi:10.21608/bfemu.2021.175893

Law of Velocity Distribution for Turbulent Boundary Layer with Adverse Pressure Gradient over Rough Surface.

Document Type : Research Studies

Authors

¹ Assistant Professor., Mechanical Power Engineering Department., Faculty of Engineering., El-Mansoura University., Mansoura., Egypt.

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

10.21608/bfemu.2021.175893

Abstract

The aim of this investigation is to obtain a law for the velocity distribution in turbulent boundary layer in the presence of different surface roughness and adverse pressure gradient. This work has been developed on the basis of experimental results of different investigators [1:4] land on the velocity law in turbulent flow over rough surface [5].
In order to obtain the numerical results for the mathematical solution outlined in this work, a computer program was constructed to perform all the necessary calculations. These results are presented in charts and can be utilised for the geometric shape of roughness. On these basis it is possible to study turbulent boundary layer for which the pressure distribution, and the ratio of the roughness height to the momentum thickness k/ᵟ ⃰⃰⃰ ⃰⃰ are defined. Moreover, this work shows also that the constant of surface roughness function, C_r, varies with pressure gradient in form of Euler number for different ratios k/ᵟ ⃰⃰⃰ ⃰⃰ . This contradicts suggestions of previous investigations.