Abstract
In the duct having a large divergence angle of square cross section, a slight difference of state of flow occured in the neighborhood of throat wall surface at the upstream inlet and in its four corners grows rapidly at the inlet of divergence duct and makes the entire flow in the duct not uniform unsteady flow. Also in the case of a rapid velocity of flow, a separation from the wall surface occurs, however, the state of separation is different in the corners and the center of wall surface. A reversed stream occurs in the place where the separation takes place. Furthermore, secondary flow occurs in the four corners.
The state of flow and the intensity of turbulence in the neighborhood of L/W=1.0 in the duct where such an unstationary, complex flow exists and its divergence angle is 12° were investigated and concluded.
