Observation of the Vortical Flow over a Yawed Delta Wing

The development and formation of the leading-edge vortices due to the change in the angle of attack, alpha, and yaw angle, theta, for a unique cross-flow plane at a dimensionless distance of x/C = 0.8 from the apex of the stationary delta wing with a sweep angle of Lambda = 40 degrees were observed using stereoscopic particle-image velocimetry (stereo-PIV). In addition, the experiments were conducted on three different cross-flow planes such as x/C = 0.6, 0.8, and 1 using dye visualization to reveal the development of leading-edge vortices over the delta wing. The angle of attack was varied within the range of 7 <= alpha <= 17 degrees and the yaw angle was varied within the range of 0 <= theta <= 8 degrees. The vortical flow structure and loadings toward the wing surface due to the fluctuations and unsteadiness in the flow structure near the delta wing are investigated using time-averaged parameters such as streamlines, contours of vorticity distributions, Reynolds stress correlations, distributions of turbulent kinetic energy, vertical velocity, and RMS of vertical velocity fluctuations. DOI: 10.1061/(ASCE)AS.1943-5525.0000163. (C) 2012 American Society of Civil Engineers.