Numerical Characterization of Kelvin-Helmholtz Instabilities (KHI) in Supersonic Nonequilibrium Flows

The project looks at numerical analysis and multi-physics simulations to characterize Kelvin-Helmholtz Intsabilities (nKHI) in high-enthalpy flows. This will be realized by defining the sensitivities of nKHI’s dynamics with respect to the shock wave patterns that determine the occurrence of a velocity shear.

Fluid mechanics instabilities are fundamental mechanisms that can lead to the onset of a chaotic flow regime where enhanced mixing and heat exchange take place. In particular, one such important mechanism occurs when an interface exists separating regions of fluid that slide one over the other resulting in a sharp variation of velocity across the interface, referred to as the Kelvin-Helmholtz instability (KHI). Depending on the flow conditions and fluid properties, the inter-face may become unstable and any small perturbations could progressively amplify and eventually transition into a fully nonlinear behaviour. While the behaviour of KHI is well-established in the case of ideal flows, the understanding and characterization of the genesis and nonlinear evolution of KHI in thermochemical nonequilibrium (e.g high-Mach flight of transatmospheric vehicles) and/or ionized conditions (e.g. plasma dynamics in planetary magnetosphere) still requires research efforts. KHI in hypersonic flow over a 2D compression corner. Numerical Schlieren. The project is conceived to further the current knowledge on nonequilibrium KHI with a particular focus on nKHI’s role in the design of aerospace systems/technologies designed to operate at regimes where the careful assessment of nonequilibrium physics and aerothermal loads is key to the operability and survivability of the system.

This funded project covers Home/EU tuition fees, and provides a monthly stipend (currently £14777 a year, subject to increase), for the 3 year period of research study.

Proposed Start date: June to December 2019