Large-Eddy Simulation of Tip Vortex Flow at High Reynolds Number

Abstract

Simulations using up to 300 million grid points are performed on the Earth Simulator in Japan, the fastest supercomputer in the world. The present work is the first attempt to simulate a finite blade with a tip in an incident flow and its associated tip vortex and acoustic field at a Reynolds number in the order of a million using direct compressible LES (Large-Eddy Simulation). For validation purposes, the flows around a NACA0012 blade section as well as finite blade at lower Reynolds number are simulated. It is a wall resolved simulation using the Smagorinsky eddy viscosity model. Angles of attack between 5 and 11 degrees are studied at Reynolds numbers ranging from 4.06×10 5 to 2.87×10 6 . The simulation results showed that the tip vortex plays a major role in aerodynamic noise generation. The present large-scale simulation can provide information about the physical phenomena causing tip vortex flow and tip noise at high Reynolds numbers. This information can be used in various engineering applications such as aerospace and wind energy and could help to design blade tips for reduced noise emission.