The characteristic coefficient analysis of the pressure curve type based on the classification method

Perforated pipes are widely used in applications such as drainage, irrigation and ventilation. The variation in the pressure head, h, in a perforated pipe follows a certain pattern. By analyzing h variation patterns at the tail ends of perforated pipes on flat slope, and the characteristic coefficient of the perforated pipe was proposed. According to the value of characteristic coefficient of the perforated pipe, perforated pipes are classified into three types, namely, short, medium and long pipes. In addition, a method for determining the type of perforated pipe based on its characteristic coefficient and length-to-diameter ratio is provided. Furthermore, on the condition of long perforated pipe, based on the locations of the maximum and minimum h values, the slope at which the perforated pipe is laid and the head loss ratio along the length of the perforated pipe, h curves are classified into five types. The experimental results demonstrate that the experimental data exhibit a variation pattern consistent with that of the calculation results, indicating that the classification of pressure head curves is, to a certain degree, reasonable and applicable.