Free surface liquid metal targets are considered in several high power targets as a tool to produce secondary particles, since their power density exceeds material sustainable limits. Many target designs consider due to the high power deposited in the liquid a concave formed back plate in order to yield a higher boiling point. Upstream the free surface target domain the liquid metal flow is conditioned by a nozzle. However, a back-wall curvature as well as a concave shaped exit nozzle contour can lead to the occurrence of secondary motions in the flow caused by Taylor-Go¨rtler (TG) instabilities. These motions may impact the hydrodynamic stability the flow and also lead to an undesired heat transfer from the hottest region produced within the liquid target towards the uncooled back plate. In this study, the suitability of the Large Eddy Simulation (LES) technique to simulate the formation, development and destruction TG instabilities in transitional and turbulent boundary layers was tested by comparing the simulation results with experimental data reported in literature. All comparisons exhibit a qualitative and quantitative good agreement between experimental data and numerical predictions regarding the mean flow parameters and unsteady large-scale structures caused by TG instabilities.
Large-eddy simulations of adverse pressure gradient turbulent boundary layers
