PIV Measurements and Validation of RANS Solutions for Plane Turbulent Impinging Co-Flowing and Angled Jets at Moderate Reynolds Numbers

Abstract

Turbulent impinging jet (TIJ) flows are a canonical type of flow that is present in nature and in a wide range of industrial applications, making their study indispensable. Among them, multiple co-flowing and angled jets offer possibilities for various practical applications. However, fundamental information on these particular jet configurations is scarce, and there is also a lack of data for validating numerical simulations of these jet flows. Therefore, this paper presents an experimental analysis of isothermal plane turbulent impinging co-flowing and angled jets at moderate Reynolds numbers (Re_jet ≈ 8,700 and 10,000) and height-to-width ratio (γ = 40.5) utilizing 2D particle image velocimetry (PIV). It also validates the results of several RANS turbulence models that are commonly used for simulating single straight TIJs: standard k-ε (SKE) model, realizable k-ε model (RKE), renormalization group (RNG) k-ε model, baseline (BSL) k-ω model, shear-stress transport (SST) k-ω model, and a Reynolds-stress model (RSM). The analysis and validation focus on detailed velocity measurements while also providing insights into turbulence parameters. Results reveal strong similarities between the two analyzed TIJs and single straight TIJs at the developed free-jet (or combined jet region for the co-flowing jets configuration) and impingement regions. The validation study demonstrates that relatively inexpensive RANS simulations in combination with typical k-ε turbulence models are capable of resolving the mean velocity field of the two investigated TIJ configurations with good accuracy, which is especially the case for the RNG k-ε turbulence model that yields a very good match with the PIV data throughout.