BASIC STUDY ON THE SCALE EFFECT OF THE VISCOUS FLOW AROUND A MARINE PROPELLER

This paper describes the mechanism of the scale effect on the viscous flow around a marine propeller. Using a Reynolds Averaged Navier-Stokes code developed by the author, a series of turbulent flow computations are made around a three-bladed marine propeller at four Reynolds numbers in the range between a model and a full scale condition. The results show the thrust coefficient (KT) tends to increase as the Reynolds number gets higher and vice versa for the torque coefficient. The mechanism of the scale effect on KT is further investigated by decomposing it into pressure (KTP) and friction component (KTF). The scale effect on KTP is shown to have the same order as that of KTF and it reveals the importance of the scale effect on KTP, which are neglected in the powering estimation method used in the design process. By comparing computed results of surface pressure and displacement thickness distributions at model and full scale Reynolds number, the mechanism of the scale effect on KTP is understood as the increase of the effective camber of the blade section due to the decrease of the displacement thickness as the Reynolds number is higher. Decomposition of KTP into the spanwise direction shows the magnitude of the scale effect is much larger at the tip than at mid-span sections, which suggests the close relationship with three-dimensionality of the flow structure.

• Supplemental Notes:
  • J Kansai Soc Naval Arch, n 222, Sept 1994, p 33 [7 p, 7 ref, 3 tab, 11 fig]
• Authors:
  • Uto, S
• Publication Date: 1994

Language

• Japanese

Subject/Index Terms

• TRT Terms: Fluid dynamics; Viscous flow
• Uncontrolled Terms: Finite volume method; Scale effect
• Old TRIS Terms: Propeller flow
• Subject Areas: Marine Transportation;

Filing Info

• Accession Number: 00709782
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Aug 14 1995 12:00AM