Gas impingement jets are widely applied in industrial cooling processes. In continuous heat treatment lines of steel, aluminium and copper strips, impingement jet nozzle systems are utilised to achieve rapid cooling or heating. The heat transfer depends on the flow but also on the geometric parameters such as nozzle to strip distance and the nozzle shape. The key challenge while designing cooling sections is to determine the performance of those nozzle systems or their Nusselt number respectively. Jet cooling sections are challenging to model with computational fluid dynamics or in an experimental set up. Yet, RANS-turbulence models are a cost-effective way to predict Nusselt numbers. In this work the capability of the ANSYS generalized k-omega (GEKO) two-equation turbulence model to determine the local and integral Nusselt number of an impinging air jet is evaluated. The results are contrasted to experimental investigations.