Construction of three-dimensional flow structure out of two-dimensional steady flow field velocity measurements

Two-dimensional particle image velocimetry (PIV) is used to obtain a set of parallel vector maps in spanwise direction over the delta wing configurati on ELAC. The out-of-plane velocity component is then constructed by applica tion of continuity equation. This yields the whole three-dimensional separa ted flow field over the leeward side of the model. The spatial resolution o f the measurements enables a detailed examination of the three-dimensional flow structure. The growth and the helical structure of primary vortex as w ell as smaller flow structures caused by secondary separation can be observ ed. Accuracy of the constructed velocity component is estimated with help o f a numerically obtained three-dimensional dataset of the flow field around this configuration. The reconstruction procedure was applied to this data set taking the experimental uncertainty and the grid spacing of the PIV mea surements into consideration. A comparison of reconstructed out-of-plane co mponent and data of the numerical solution of Navier-Stokes equations resul ts in a promising low error. A statistical analysis of different procedures allows interpretation of reconstruction capabilities.