Study on pressure head distribution along the gravity flexible hoses

Based on the principle of hydraulics,the general equation for head loss and the formula for calculation of pressure head along the flexible hoses were worked out,and the method for determination of the maximum and minimum heads and their positions was given.The comparison of the calculated results with the measured data demonstrates that the method is of certain reasonability,and can be used for practical calculation under the condition that is similar to or accords with the experimental condition,providing a basis for judgment of whether the outflow from droppers of flexible hoses can meet the allowable deviation ratio of flow rate and for calculation of the uniformity coefficient of micro-irrigation.