According to Eq. 5, the blowing positions should be converted to dimensionless values. In this study, we used the graphic method to making the blowing position dimensionless [10]. Table 2 showed all of the nondimensionalized blowing position.

In this study, Through stepwise regression analyzing of the data, a relationship between H_{0} and H/D, W, Fr' were found. The equation was described as follows:

Equation (11) was also represented in the following dimensionless form:

Equation (12) clearly indicated the index of every influence factor. The size of the index determined the importance of the factor to H_{0}. It could be seen here that the significant of the influence factor to H_{0} were in order of the blowing position, the aspect ratio, the modified Froude number and the liquid-gas density ratio. Among them, the blowing position was the most remarkable.

Table 2 The dimensionless of the blowing positions