Prediction of the Development of Turbulent Boundary Layers on Rough Walls Based on the Integration Method

The effect of wall roughness on the turbulent flow has long been an important research topic in the field of fluid dynamics. The development of turbulent boundary layers on rough walls with pyramid roughness elements in zero pressure gradient is conducted in this paper, using the integration method of boundary layers. Firstly, the pyramid roughness texture is characterized with two geometric statistical parameters, and the specific form of the roughness function is next determined by fitting the experimental data. Then, the streamwise development of the boundary layer thickness and local friction factor are solved based on the momentum integral equation and the wall law. The calculation is observed to be in reasonable agreement with the experimental data, which validates the accuracy and simplicity of the integration method in predicting the development of turbulent boundary layers on rough walls.