Abstract:Jets are widely used in various hydraulic applications.To observe the evolution of flow field and to investigate the mechanism of a submerged jet,Large eddy Simulations(LES) was utilized to simulate flow field with finite volume method (FVM) for discretization and PISO method for pressure calculation.From the analysis of the evolution of pressure field,the contours of pressure presented to be a cluster of concentric circles,and high pressure and low pressure circles appeared alternately along the jet axis.During the jet impinging, the concentric circles were moving along the jet with deformation,further splitting and merging.In the submerged jet zone and the front of jet impingement zone,the pressure in the center of concentric circles fluctuated and tended to be ascending; in wall jet zone,with a narrow range,the pressure in the center of concentric circles fluctuated at relatively low frequency.From the analysis of the evolution of velocity field,the jet was swinging and the mass of high velocity in the axis separated from main flow as time passed by.It was also found that the velocity had the negative correlation with pressure on a fixed point of jet.From the analysis of the evolution of vorticity field,two beams of vorticity in the field were distributed as the shape of lotus root and swung with time.Comparing vorticity field with pressure field,the results showed that it was vortex swinging that caused the jet swing and pressure distribution was also affected by vortices.The submerged jet field had the characteristic of randomness and was strongly turbulent.We reach the general conclusions from evolution of flow field and inherent relationship among velocity,pressure and vorticity,while there still remains many other aspects to be investigated,such as the quantitative analysis of jet swinging.