The flow investigation in a elbow draft tube is presented. After a review of the existing works related to the flow analysis of such component, the need of an experimental validation of the CFD tools is discussed with respect the practical interest of improving the matching of a runner and the draft tube. The geometry and the main characteristics of the test model is described and the pressure recovery coefficient is provided in an extended operating range. The instrumentation of the draft tube and the LDA system for flow survey are described. After the discussion of the influence of the boundary conditions and the mesh size with respect to the CFD analysis, the results of flow analysis are compared to the available experimental data for 3 operating points.