Critical Standard Normalized Rapid Suppression Hydraulic Index and Its Estimation

Abstract

As a standard to by which characterize the ability of ships to ascend rapidly, the rapid suppression hydraulic index is the main indicator of the rapid regulatory effect and an important component of channel engineering research. This study reviewed the current determination methods and forms of expression of the rapid suppression hydraulic index and revealed that the existing comprehensive indices of unit energy have obvious disadvantages, such as critical standards not being unified. Based on the balance principle of a ship’s effective propulsion and navigation resistance, according to the unified idea of the critical rapid suppression index, the dimensionless expression of the critical standard normalized rapid suppression hydraulic index was derived. The concepts of flow velocity fraction, slope fraction and their combined rapid suppression index are proposed, and the assessment method of rapid forming and suppressing with the critical standard of 1 is provided. Using an example, we verified the feasibility and convenience of the application of the critical standard normalized rapid suppression hydraulic index in judging rapid formation reaches, navigation obstruction areas and the comparison of the ability of several ship types to ascend rapidly. Based on various ship slope flow rapid suppression indices tested by real ship tests and theoretical analysis through the dimensions, main influencing factors and regression analysis, we introduced the dimensionless power load ratio and established an empirical formula for estimating the flow velocity fraction and slope fraction by the main parameters of the ship type, which can provide a reference for determining the rapid suppression hydraulic index when lacking detailed ship type data. The application scope of the estimated formula is discussed. The methods and data for rapids regulation are provided, which is more convenient for rapids remediation projects, will reduces rapids hindering navigation and then will develop the shipping industry of mountainous rivers to promote the sustainable development of mountainous economic construction.