PIV and CFD Analyses of Vortical Flow over a Yawed LEX-Delta Wing Configuration

Abstract

A Particle Image Velocimetry(PIV) technique is utilized for the analysis of vortical flow field over a 65 o flat delta wing with the leading edge extension(LEX). Instantaneous cross -flow velocity vectors are measured at a series of stat ions in the chordwise direction through the PIV system consisting of a high -intensity Nd:YAG laser, a high -resolution CCD camera, a commercial PIV software on a PC, etc. The average velocity fields are also obtained based on the ensembles of the instantane ous velocity vectors. Zero and –5 o sideslip angle cases are investigated at the angle of attack of 24 o with the free stream velocities of 10, 20 and 30 m/sec, respectively. The velocity measurements conducted in a medium -sized subsonic wind tunnel(3.5m · 2.4 5m) at Korea Air Force Academy are compared with the previously obtained visualization and hot -wire results. The comparison shows a good agreement with each other, providing the validity of the PIV technique as well as indicating its effectiveness to inves tigate complex flow fields in a fairly large -scale wind tunnel facility. The data obtained from the PIV measurements will be used for the validation of a CFD code for the LEX -delta wing configuration. Once validated, the PIV technique along with the CFD me thod will be applied to various test cases for a parameter study.