Wind Tunnel Experiments with Flexible Plates in Transonic Flows

Abstract

The evolution of adaptive shock control bump (SCB) design has seen the system flexibility increase to a point where the aerodynamic loading can affect the deformation of the plate. By studying the effects of a flexible plate subject to transonic flow the fluid structure interaction can be investigated. In this study an array of thin plates (0.4 and 0.6 mm) with different aspect ratios (1 and 1.33) are exposed to a Mach 1.4 normal shockwave. PIV is used in combination with Schlieren imaging to provide a detailed view of the flow curvature surrounding the plate as well as the global shock structure. A technique that extracts the plate deformation from the PIV images is also presented which provides fluid and structural information for each test. The relationship between plate and flow angle is discussed as well as the effect of plate stiffness and free stream influence of each plate configuration.

Optimisation of adaptive shock control bumps with structural constraints

“…These dimensions were selected to match the parameters used in a related experimental study in a high speed wind tunnel, the results of which are reported elsewhere [18]. The stream-wise length of the flexible region (200 mm) corresponds to a bump length l b = 0.2c for a nominal aerofoil chord of 1 m. Full fixation against translation and rotation is imposed on the upstream and downstream ends of the flexible region.…”

Compression Ramp Induced Shock-Wave/Turbulent Boundary-Layer Interactions on a Compliant Material

“…shockwaves. They can be created either passively through a panel that deflects due to the surrounding flow or actively through the usage of actuators placed beneath the panel that deflect it in a controlled manner [13]. shows the drag reduction in the wake for an airfoil with a SCB compared to a clean airfoil.…”

“…The strength of shock bifurcation can be seen to depend heavily on shock location, and the adverse effect of the bump geometry can be seen in the thickening of the boundary layer past the bump with the eventual formation of a shear layer as marked in Figure 1.6f. However, Jinks et al [13] recently investigated in depth both passive and active flow control methods using SCB, and they recommend additional actuators or limit stops to maintain optimal shapes even when in off-design performance conditions. Overall, there is strong evidence towards SCB as a successful application of FSI in the transonic regime.…”