A large-eddy simulation of the flow over a high-lift airfoil configuration consisting of a slat and a main wing is performed at a freestream Mach number M=0.16 and an angle of attack of 13°. The Reynolds number, based on the clean chord length and the freestream velocity, is Re=1.4·10
. The results show similarities between the turbulent structures of the slat cusp shear layer and a free shear layer and an impinging jet. The periodical occurrence of rollers and streamwise orientated rib vortices contributes essentially to the generated sound.