HYDRAULIC RESISTANCE OF TURBULENT FLOWS IN ROUGH PIPES USING DRAG REDUCING AGENTS

Turbulent drag reduction with polymer additive in rough pipes

Mathematical modeling of hydraulic resistance in pipes with rough walls

Study patterns of flow in pipes with rough walls can be considered relevant, as the use of rough surfaces is a method of heat transfer. In the theoretical study of heat transfer processes in heat exchangers and devices used in various fields of technology, it is very important to know the basic laws of flow in rough pipes in turbulent regime. Flow patterns for rough pipes differs from the behav...

Turbulent flow in smooth and rough pipes.

Recent experiments at Princeton University have revealed aspects of smooth pipe flow behaviour that suggest a more complex scaling than previously noted. In particular, the pressure gradient results yield a new friction factor relationship for smooth pipes, and the velocity profiles indicate the presence of a power-law region near the wall and, for Reynolds numbers greater than about 400x103 (R...

Effective medium theory for drag-reducing micro-patterned surfaces in turbulent flows.

Many studies in the last decade have revealed that patterns at the microscale can reduce skin drag. Yet, the mechanisms and parameters that control drag reduction, e.g. Reynolds number and pattern geometry, are still unclear. We propose an effective medium representation of the micro-features, that treats the latter as a porous medium, and provides a framework to model turbulent flow over patte...

Turbulent friction in rough pipes and the energy spectrum of the phenomenological theory.

The classical experiments on turbulent friction in rough pipes were performed by Nikuradse in the 1930s. Seventy years later, they continue to defy theory. Here we model Nikuradse's experiments using the phenomenological theory of Kolmogórov, a theory that is widely thought to be applicable only to highly idealized flows. Our results include both the empirical scalings of Blasius and Strickler ...