Experimental characterization of the hypersonic flow around a cuboid

Abstract

Understanding the hypersonic flow around faceted shapes is important in the context of the fragmentation and demise of satellites undergoing uncontrolled atmospheric entry. To better understand the physics of such flows, as well as the satellite demise process, we perform an experimental study of the Mach 5 flow around a cuboid geometry in the University of Manchester High SuperSonic Tunnel. Heat fluxes are measured using infrared thermography and a 3D inverse heat conduction solution, and flow features are imaged using schlieren photography. Measurements are taken at a range of Reynolds numbers from 40.0 × 10 3 to 549 × 10 3. The schlieren results suggest the presence of a separation bubble at the windward edge of the cube at high Reynolds numbers. High heat fluxes are observed near corners and edges, which are caused by boundary-layer thinning. Additionally, on the side (off-stagnation) faces of the cube, we observe wedge-shaped regions of high heat flux emanating from the windward corners of the cube. We attribute these to vortical structures being generated by the strong expansion around the cube's corners. We also observe that the stagnation point of the cube is off-centre of the windward face, which we propose is due to sting flex under aerodynamic loading. Finally, we propose a simple method of calculating the stagnation point heat flux to a cube, as well as relations which can be used to predict hypersonic heat fluxes to cuboid geometries such as satellites during atmospheric re-entry.

Security of Distributed Parameter Cyber-Physical Systems: Cyber-Attack Detection in Linear Parabolic PDEs

“…We assume that the distributed parameter plant exhibits stable behavior under the control system, and hence, α < 0. The PDE (1)-( 2) represents systems involving diffusion (captured by u xx ) and reaction (captured by αu), for example, thermal systems [24][25][26].…”

Aerodynamics of inclined cylindrical bodies free-flying in a hypersonic flowfield

“…Aerodynamics of simple-shaped bodies in high-speed flows is generating renewed interest in the field of atmospheric entry of meteoroids, space debris and separating components of launch systems. Especially in the past decade, the characterization of flowfields around single (Lee et al 2017;Seltner et al 2019;Rees et al 2020;Grossir et al 2020) and multiple bodies (Laurence et al 2012;Marwege et al 2018;Park and Park 2020;Register et al 2020) has gained importance with respect to fragmentation, demise and separation behaviors of these space objects undergoing atmospheric entry. The determination of their flight trajectories helps to predict the impact area of uncontrolled entering spacecrafts with the objective to protect persons and properties from harm.…”

Numerical and experimental studies of the hypersonic flow around a cube at incidence

“…The heating rates to cuboids were first studied in the reports of Crosby & Knox [13], and Laganelli [14], who experimentally measured heat fluxes to a cube in a Mach 8 flow at discrete locations using thin-foil calorimeters. More recently, measurements of the hypersonic heat fluxes to a cube were made using InfraRed Thermography (IRT) [15] so that the heat fluxes across the entire surface of the cube could be measured, rather than just at discrete points on the geometry. These IRT measurements identified regions of increased heating along the streamwise edges of the cube, which were attributed to the presence of vortical structures emanating from the cube's sharp corners.…”

“…Using both numerical and experimental methods, this work will investigate the effect of small angles of incidence on the hypersonic flow-field around a cuboid. The numerical simulations will provide a method to visualize the 'hot wedges' identified in [15] which significantly increase the heat fluxes to certain regions of the cube when it is at zero incidence, as well as a method to investigate the effect of incidence on these flow structures. The experimental flows will supplement the numerical results by providing valuable validation data.…”

“…The experimental flows will supplement the numerical results by providing valuable validation data. These experimental flows will be visualised with schlieren photography, and the heat fluxes will be calculated by applying a 3D inverse heat conduction problem (IHCP) to IRT temperature data [15]. Finally, we aim to use the combined experimental and numerical datasets to draw conclusions about the effect of small angles of incidence on the hypersonic heat fluxes to faceted shapes.…”