Analysis of Influence of Different Parameters on Numerical Simulation of NACA0012 Incompressible External Flow Field under High Reynolds Numbers

Lu Yang,Guangming Zhang

doi:10.3390/app12010416

Abstract

Currently, influence analysis of simulation parameters, especially the trailing edge shape and the corresponding modeling method on the force coefficients of NACA0012 under a high Reynolds number, is relatively sparse. In this paper, two trailing edge shapes are designed by three modeling methods and combined with three far-field distances to establish eighteen two-dimensional external flow fields. The same number of structured grids are generated by a unified grid strategy and the SST k-omega and the Spalart–Allmaras models are adopted to solve the NS equations to realize the numerical simulations. Unlike under low Reynolds numbers, the analysis results show that although the accuracy difference between the sharp trailing edge and the blunt trailing edge decreases as the attack angle range increases, the former is preferred in all studied ranges. As to the corresponding modeling methods, the NACA4 and the definition formula are preferred, the choice of which depends on the studied range. In particular, a greater number of data points adopted into the definition formula is not necessarily better. Considering the error ratios comprehensively, the simulation configurations of sharp trailing edge + 20 m far-field distance + SA/SST/SST/SST/SST/SA turbulence model obtains optimal simulation effects.

Highlights

The accurate prediction of flight environments plays a vital role in designing and optimizing aircraft [1,2]
The results show that for the wavy airfoil, the Cl data are reduced when the angle of attack (AOA) is less than the baseline stall angle, while when the AOA is larger than the baseline stall angle, the Cl data are increased
The number of data points adopted into the definition formula dependencies is discussed

Summary

Introduction

The accurate prediction of flight environments plays a vital role in designing and optimizing aircraft [1,2]. According to different flight velocities, the vehicle will suffer different external flow environments, including incompressible external flow fields and compressible external flow fields. The compressible external flow field during the ascent of the vehicle is discussed in another paper by Lu and Guangming [3]; in this paper, we study the incompressible external flow field. The aircraft is immersed in the external flow field, and the fluid flowing across the airfoil surface will generate pressure in the direction perpendicular to the surface and shear force in the direction parallel to the surface. The resultant force of pressure and shear force in the flow direction is called drag, and the component perpendicular to the flow direction is called lift. With the development of computer hardware and numerical simulation technology, CFD has been adopted to solve the governing equation of fluid motion to obtain drag and lift [6,7]

Methods

Results

Discussion

Conclusion