Theoretical and experimental study of scour depth by submerged water jet

The characteristics and working principles of the impinging by submerged water jet are analyzed, and the relevant mathematical model is optimized based on Rajaratnam's theoretical and experimental study. A new mathematical model is constructed by adding an important parameter called impinging angle. A new experiment is designed according to the working conditions of various impinging distances and angles. In combination with the experiment data and with the use of the curve fitting method, the functional relationship between the impinging distance and angle as well as the coefficient C-4 is obtained. The experiment results show that the scour depth decreases as impinging distance increases, followed by a trend from decline to rise before falling again; those two turning points occur within the range of 20d-25d. The scour depth constantly increases with rising impinging angle, and the maximum and minimum increasing ranges can reach 180% and 50%, respectively, with the impinging angle increasing from 40 degrees to 90 degrees