ah, this one i regognise imediatly as a turbulent jet ( joking ;-) http://images.google.nl/imgres?imgurl=http://vtchl.uiuc.edu/basic-research/environmental-hydraulics/turbulent-jets/jetK4.jpg&imgrefurl=http://vtchl.uiuc.edu/basic-research/environmental-hydraulics/turbulent-jets/&h=204&w=300&sz=22&hl=nl&start=2&tbnid=cHA-btqrb3_4yM:&tbnh=79&tbnw=116&prev=/images%3Fq%3DJetK4%26svnum%3D10%26hl%3Dnl%26lr%3Dlang_en%26sa%3DG