Design and investigation of an aeroelastically scaled delta-wing wind tunnel model for dynamic load analysis

Abstract The prediction of complex flow phenomena on elastic delta wing structures is of significant importance for the aircraft design processes. For this reason, conducting wind tunnel experiments on elastically deformable delta wings is of great interest, particularly for validating numerical simulations. In this work, a 3D-printed half model of a delta-wing configuration called Model53e is investigated in the wind tunnel facility A of the Chair of Aerodynamics and Fluid Mechanics at the Technical University of Munich. This model features a deployed leading edge slat and adjustable trailing edge flaps. It is structurally scaled to fit the dynamic characteristics of a fictitious full-scale configuration. In terms of the structural design, a rib and spar structure was chosen for the wing. The flaps are fabricated of solid material. A connection of the flaps to the wing is provided by bolted joints. Multiple flap positions from − 30° to 30° are investigated for each flap. Transient pressure sensors and accelerometers are mounted on the model for the measurements in the wind tunnel. Furthermore, an underfloor balance system is used to record the global forces and moments acting on the model. The measurements are carried out at Reynolds numbers of $$Re = {1.0\times 10^{6}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>R</mml:mi> <mml:mi>e</mml:mi> <mml:mo>=</mml:mo> <mml:mrow> <mml:mn>1.0</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> </mml:mrow> </mml:mrow> </mml:math> and $$Re = {1.7\times 10^{6}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>R</mml:mi> <mml:mi>e</mml:mi> <mml:mo>=</mml:mo> <mml:mrow> <mml:mn>1.7</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> </mml:mrow> </mml:mrow> </mml:math> for angles of attack from 0° to 32°. As a result, time-averaged global forces and moments and transient pressure and acceleration data are recorded for a set of investigated cases. In addition, particle image velocimetry measurements have been conducted to quantify the flow field above the wing at distinct cross-flow planes. The analysis of the transient pressure transducers reveals large pressure fluctuations between 18° and 24°. Analyzing the frequency spectrum of the transient pressure data indicates that vortex bursting causes high narrow-band fluctuation levels denoted as buffet frequencies. Flap deflections lead to minor changes in the corresponding buffet frequency. In addition, the acceleration sensors exhibit increased values between 17° and 25° associated with the structural response called buffeting. These experimental results are used to validate aeroelastic simulations by taking into account dynamic structural deformations. For the Computational Fluid Dynamics simulations, a URANS approach with a $$k-\omega SST$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>k</mml:mi> <mml:mo>-</mml:mo> <mml:mi>ω</mml:mi> <mml:mi>S</mml:mi> <mml:mi>S</mml:mi> <mml:mi>T</mml:mi> </mml:mrow> </mml:math> model is conducted for $$\alpha ={20}^{\circ }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>α</mml:mi> <mml:mo>=</mml:mo> <mml:msup> <mml:mrow> <mml:mn>20</mml:mn> </mml:mrow> <mml:mo>∘</mml:mo> </mml:msup> </mml:mrow> </mml:math> and $$\alpha ={25}^{\circ }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>α</mml:mi> <mml:mo>=</mml:mo> <mml:msup> <mml:mrow> <mml:mn>25</mml:mn> </mml:mrow> <mml:mo>∘</mml:mo> </mml:msup> </mml:mrow> </mml:math> for undeflected flaps to compare the results to the experimental data. The global force and moment data, as well as the structural response data, are predicted well, while larger differences in the experimental results occur for local aerodynamic data.