Numerical investigation of frequency-amplitude effects of dynamic morphing for a high-lift configuration at high Reynolds number

Abstract

Purpose The purpose of this study illustrates the morphing effects around a large-scale high-lift configuration of the Airbus A320 with two elements airfoil-flap in the take-off position. The flow around the airfoil-flap and the near wake are analysed in the static case and under time-dependent vibration of the flap trailing-edge known as the dynamic morphing. Design/methodology/approach Experimental results obtained in the subsonic wind tunnel S1 of Institut de Mécanique des Fluides de Toulouse of a single wing are discussed with high-fidelity numerical results obtained by using the Navier–Stokes multi-block (NSMB) code with advanced turbulent modelling able to capture the predominant instabilities and coherent structure dynamics. An explanation of the dynamic time-dependent grid deformation is provided, which is used in the NSMB code to simulate the flap’s trailing-edge deformation in the morphing configuration. Finally, power spectral density is performed to reveal the coherent wake structures and their modification because of the morphing. Findings Frequency of vibration and amplitude of deformation effects are investigated for different morphing cases. Optimal morphing regions at a specific frequency and a slight deformation were able to attenuate the predominant natural shear-layer frequency and to considerably decrease the width of the von Kármán vortices with a simultaneous increase of aerodynamic performances. Originality/value The new concept of future morphed wings is proposed for a large scale A320 prototype at the take-off position. The dynamic morphing of the flap’s trailing-edge is simulated for the first time for high-lift two-element configuration. In addition, the wake analysis performed helped to show the turbulent structures according to the organised eddy simulation model.

Near Stall Unsteady Flow Responses to Morphing Flap Deflections

“…The use of continuous actuation by means of morphing surfaces (e.g., [12]) or vibrating flaps (e.g., [13]) has been the subject of a few recent studies. For example, the ability of periodic surface morphing to mitigate flow separation and reduce drag at a low Reynolds number of 50,000 was demonstrated experimentally [12,13].…”

“…The use of continuous actuation by means of morphing surfaces (e.g., [12]) or vibrating flaps (e.g., [13]) has been the subject of a few recent studies. For example, the ability of periodic surface morphing to mitigate flow separation and reduce drag at a low Reynolds number of 50,000 was demonstrated experimentally [12,13]. In a different experiment at a high Reynolds number of 1 million, Jodin et al [14] showed that a substantial reduction in flow instabilities could be obtained using a vibrating TEF, in addition to an increase in the aerodynamic efficiency, if the flap vibrations are set at optimal frequencies and amplitudes.…”

Flow analysis around a VTOL aircraft near stall conditions and application of Active Flow Control to enhance the aerodynamic performances at real flight conditions

“…NSMB solves the Reynolds-averaged Navier Stokes equations for compressible flows on multi-block structured grids. NSMB offers all functionalities of a modern CFD code used for aerospace applications, among others, ALE (Arbitrary Lagrangian Eulerian) approach [18], turbulence models [19], chemistry modelling, grid flexibility, FSI (Fluid-Structure Interactions) coupling such as morphing wings modelling ( [20][21][22]), Chimera overlapping technique [23]. Space discretization schemes include 2nd-and 4th-order central schemes with artificial dissipation and various upwind schemes (Roe, AUSM, Van Leer ...) up to 5th order.…”

“…NSMB includes also a large variety of well tested and validated turbulence models that are standard in the aeronautical industry, like the one-equation Spalart-Allmaras [24], the Organized Eddy Simulation model [19,25], or the two-equation by Menter [26], that have been applied in the present study. Different morphing concepts are also implemented [13,[27][28][29][30] in the code. Unsteady simulations are made using the dual time stepping approach or using Newton's approach.…”

Unsteady CFD simulations for Active Flow Control

“…The SMS project has been coordinated by Institut de Mécanique des Fluides de Toulouse (IMFT). In the context of this project and at a subsonic regime, the studies [1,2] investigated the morphing through vibration and slight deformation of the near trailing edge region using piezoactuators. Actuation frequencies in the range (60Hz -400Hz) associated with low-amplitudes of deformation (order of 1mm) were examined.…”