Research article

Numerical simulation study on the drag reduction characteristics of grooves-microbubbles coupling surfaces

¹ School of Mechanical Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
² Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge UB8 3PH, UK
³ R&D Centre, Wuhan Second Ship Design & Research Institute, Wuhan 430205, China

^* Corresponding authors: xizhi.sun@brunel.ac.uk; thewutao@163.com

Received: 16 January 2024
Accepted: 29 February 2024

Abstract

Surface drag reduction technologies can significantly reduce the resistance during ship navigation, enhancing speed, efficiency and adaptability under various operating conditions. This paper uses numerical simulation technology to analyze the drag reduction characteristics of grooved and grooves-microbubbles coupling surface, focusing on the effects of groove width, gas flow rate, and liquid flow velocity on the drag reduction performance. The research results indicate that the grooved surface is suitable for full surface drag reduction at velocity below 3 m/s with a maximum drag reduction rate of 4.02%. Microbubbles can greatly improve the drag reduction effect of the grooved surface, and the drag reduction effect of the coupling surface gradually increases with the gas flow rate increases. The maximum drag reduction rate can reach 89.86% at the gas inlet velocity of 1 m/s. The liquid flow velocity has a significant impact on the drag reduction. In both the groove model and the coupling model, the drag reduction rate initially rises and then declines with the liquid flow velocity increases.