Experimental Analyses on the Flow Field Characteristics of the AVT-183 Diamond Wing Configuration (Invited)

Abstract

Comprehensive experimental flow field investigations are presented on a 53 • leadingedge sweep diamond wing configuration with rounded leading-edge contour as part of the NATO Science and Technology Organization (STO) task group AVT-183 (Applied Vehicle Technology panel). The results obtained in a low speed wind tunnel facility depict the mean and turbulent flow field characteristics that are mainly dominated by a smooth surface separation with subsequent leading-edge vortex formation. Both Stereo Particle Image Velocimetry and Hot-Wire Anemometry are applied to detect the emerging flow phenomena in several chord-wise sections including near-wall data. Details of the leading-edge vortex onset and progression are analyzed and discussed. Over almost the entire length of its existence, the leading-edge vortex is characterized by retarded axial flow, showing thus vortex bursting tendencies. The corresponding turbulent fluctuations show maxima close to the evolution of the leading-edge vortex and decrease towards the trailing-edge. The obtained flow phenomena are thereby significant for the AVT-183 diamond wing configuration with its smooth surface separation due to the rounded leading-edge contour. Based on the derived flow field characteristics, a high-quality data set suitable for general CFD validation is provided.

Numerical Investigations of Vortical Flow on Swept Wings with Round Leading Edges

“…Finally, the flow physics regarding the separation mechanism could be described. The experimental and numerical results of AVT-183 are published by Boelens et al [49,50], Hövelmann et al [51,52], Hitzel et al [53], and Frink [54]. Particularly, the description of the separation mechanism process described by Frink [54] should be taken into account as a reference for the present investigations.…”

Numerical Analysis of Incipient Separation on 53-Deg Swept Diamond Wing

“…Measurements were obtained during the TUM-AER experiments [4,5] in 1-degree increments in angle of attack from α=10° to 15°. Since the focus of the present paper is on the incipient leading-edge separation, the majority of analysis will be presented at the α=12° condition.…”

“…The peniche standoff distance is 0.075c R , where the root chord is c R =1.2m. Measurements included six components of forces and moments, static surface pressures, unsteady surface pressures, and off-body flow measurements of velocity and velocity fluctuations using hot-wire anemometry (HWA) and particle image velocimetry (PIV) [4,5], of which only the static surface pressure and PIV measurements were available for the present analysis. The wind tunnel model ( Figure 2) was designed as large as practical for measuring flow field velocities in the TUM-AER low-speed tunnel with the HWA/PIV techniques.…”

Leading-Edge Roughness Effects on the Flow Separation Onset of the AVT-183 Diamond Wing Configuration (Invited)

“…The time-dependent surface pressures, which are derived from unsteady Kulite pressure transducers as introduced in Section II.B, are not further regarded in the present analysis, but in a related publication by Hövelmann et al 14 There, the results of the time-dependent surface pressures are presented and discussed in the context of the turbulent surface flow field.…”

“…The available results contain aerodynamic forces and moments, steady and unsteady surface pressures, as well as mean and turbulent flow field characteristics in the vicinity of the diamond wing surface. In the present paper, the force and the steady surface pressure measurements from the first W/T campaign are regarded, while the Stereo PIV, the hot-wire and the unsteady surface pressure measurements undertaken within the other W/T campaigns are regarded in a related paper by Hövelmann et al 14 In the context of the present task group AVT-183, the obtained W/T results are also considered as comparison data for the numerous numerical computations that are available. [15][16][17][18][19][20][21][22] Beyond that, the conducted W/T investigations provide in general an extensive experimental data base for overall CFD validation, which focus on smooth surface separation with consecutive leading-edge vortex formation at a moderately swept, low aspect ratio wing with rounded leading-edge contour.…”