The mixing characteristics of jets from four rectangular nozzles with aspect ratio of 8 were investigated by numerical simulation.The first and second nozzles had different transition sections from circular to rectangular

the third nozzle had a rectangular flip which was an extension of the bottom wall of nozzle exit on the base of the first one

while the last one had two triangular flips on the left and right sides of the nozzle exit on the base of the third one.The results show that the mixing characteristics of the two nozzles with different transition sections have little difference

while the flips cause strong mixing.