환형제트 유동장의 초기지역에 있어서의 응집구조에 관한 실험적 연구

Abstract

An experimental investigation of coherent structures in the axisymmetric mixing layer of an annular jet was carried out. The Reynolds number, based on the outer diameter of the annulus, was 2.17 X 105 The flow structures of the shear layer at several downstream stations, all within 3 outer diameter distance, were examined. Conditional sampling technique was employed to educe naturally occuring large-scale structures. Coherent vorticity and coherent Reynolds stresses were, measured. It was found that the evolution of large-scale vortical structure is completed within the distance of 2 outer diameters and that the coherent Reynlods stress increases rapidly during the evolution of large-scale structure.