Due to the large number of correlations and relationships between variables and the physical phenomena involved, compressible flow simulations become very difficult or impossible if all the necessary scales and mechanisms are included and solved. Several research efforts have been made toward a more accurate flow field predictions and the current study aims to add to that knowledge base by exploring the capability of Delayed Detached Eddy Simulation employing the SST turbulence model to simulate the transonic region of over-expanded nozzle with small radius of curvature. An analysis was made of the transonic flow in axisymmetric nozzle, the paper shows the potential for using DES turbulence model to identify important internal radial flow downstream the throat region, where most RANS models fail to predict with high accuracy and in detail the structure of the flow. With small radius of curvature, the sonic line begins upstream of the throat and ends downstream due to turning flow near the wall transonic region. Comparison of the computational results with experimental data and some developed prediction methods are presented and good agreements are obtained.
compressible flow, detached eddy simulation, SST model, nozzle, over-expanded, Shock
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