Experimental and numerical Investigation on drag reduction using polymer coatings

Abstract

The phenomenon of polymer drag reduction (DR) has primarily been investigated in the context of internal flows featuring mixed solutions. However, research on non-uniform polymer DR in external flows, such as polymer coatings on the surfaces of marine applications, remains scarce. To address this gap, experimental and numerical investigations were conducted in this research to find out the DR and turbulence performance. Firstly, the experimental results are shown to demonstrate the effectiveness of polymer DR. Specifically, the drag reduction performance of a silicon polymer coating is tested under different Reynolds numbers. Then, the mesoscopic dissipative particle dynamics (DPD) method is coupled with DNS and LES methods, and the finitely extensible nonlinear elastic approach is used to validate the results obtained using this DNS/LES-DPD method. Additionally, the model is used to investigate the influence of the height of the polymer region on non-uniform polymer DR and turbulence behaviour is also investigated. The model also reveals that the polymer DR efficiency is significant even when the polymer region does not extend across the entire fluid area such as the application of polymer coating.