To get a better insight in the effect of jets on vortex development and decay, stereo-PIV measurements were performed in a towing tank behind a flapped aircraft model. The experimental data set yields the wake vortex behavior in a range that extends from the vortex formation stage up to the mid-field (approximately t* =2 corresponding to 100 wingspans for a = 0º and 60 wingspans for a=6º). Although the jet does not affect the overall circulation strength, it has a significant effect on the velocity distribution in the wake. A new Double Gaussian vortex model is introduced that perfectly fits the measurement data.