According to the passage rules of ships in the bidirectional channel,the realistic conditions of the limited number of tugboats in the port are taken into account.This paper studies the problems faced in the integrate...According to the passage rules of ships in the bidirectional channel,the realistic conditions of the limited number of tugboats in the port are taken into account.This paper studies the problems faced in the integrated scheduling optimization in terms of ship arrival and departure and tugboat allocation in two-way channel.A mixed integer programming model with minimum waiting time was established,and a heuristic algorithm was designed to solve the problem.Experimental results show that the model and algorithm in this paper can effectively solve such problems and provide support for port management.展开更多
Starting from the end of the 90s not perodic and unpredictable variations in the depth of harbor waters were observed. Long period (from 24 hours to a few days) and wide amplitude are their main features. Experience s...Starting from the end of the 90s not perodic and unpredictable variations in the depth of harbor waters were observed. Long period (from 24 hours to a few days) and wide amplitude are their main features. Experience showed that this phenomenon is a risk for harbor navigation and mooring. It may be a serious obstacle to waterside port activities. The first observation of the data does not link the super-highs and the super-dry tides to the meteorological dynamic of sea-atmosphere interaction (i.e. Storm Effect). More, the attempt to compensate for these sea depth fluctuations by means of the well-known offshore hydrobarometric inverse parameter (1 [cm] sea level variation for ǃ [hPa] atmospheric pressure variation) underestimates the amplitude of the phenomenon. In the first years of 2000, the Italian Ministry of Transport launched a national project for the definition of thee-amplitude and time of these tidal anomalous waves. The measure of harbors hydrobarometric inverse factors showed a much more intense value than the theoretical one (computed for the offshore). These amplification factors are characteristic of each harbor and can be double (in exceptional cases even more) than offshore. The delay between the arrival times of these tidal waves (induced phenomenon) respect to the time of arrival of the atmospheric pressure variation (inducing phenomenon) depends on 1) morphology of the port basin sea floor and 2) harbor and off-shre water dynamics relationship (first approximation). For these reasons the hydro barometric inverse parameter is not effectiveness computable but it can be determined statistically.展开更多
Ported wall extensions are important hydraulic structures used to reduce crosscurrents in upper approaches to locks.The effect of such extensions located upstream of a solid guard wall on flow characteristics depends ...Ported wall extensions are important hydraulic structures used to reduce crosscurrents in upper approaches to locks.The effect of such extensions located upstream of a solid guard wall on flow characteristics depends on many factors,including geometric and hydraulic parameters.In this study,the hydraulic performance of ported wall extensions was experimentally investigated in terms of the permeability coefficient,expanding angle,extension length,and flow depth.The results demonstrate that the dimensionless maximum transverse velocity is closely related to the permeability coefficient,expanding angle,and flow depth.By contrast,the dimensionless eddy length mainly depends on the permeability coefficient,expanding angle,and extension length.Furthermore,the optimum permeability coefficient increases with the expanding angle or flow depth,and it is approximately constant for different extension lengths.These results have the potential to provide direct guidance for the design of effective ported wall extensions in upper approaches to locks.展开更多
文摘According to the passage rules of ships in the bidirectional channel,the realistic conditions of the limited number of tugboats in the port are taken into account.This paper studies the problems faced in the integrated scheduling optimization in terms of ship arrival and departure and tugboat allocation in two-way channel.A mixed integer programming model with minimum waiting time was established,and a heuristic algorithm was designed to solve the problem.Experimental results show that the model and algorithm in this paper can effectively solve such problems and provide support for port management.
文摘Starting from the end of the 90s not perodic and unpredictable variations in the depth of harbor waters were observed. Long period (from 24 hours to a few days) and wide amplitude are their main features. Experience showed that this phenomenon is a risk for harbor navigation and mooring. It may be a serious obstacle to waterside port activities. The first observation of the data does not link the super-highs and the super-dry tides to the meteorological dynamic of sea-atmosphere interaction (i.e. Storm Effect). More, the attempt to compensate for these sea depth fluctuations by means of the well-known offshore hydrobarometric inverse parameter (1 [cm] sea level variation for ǃ [hPa] atmospheric pressure variation) underestimates the amplitude of the phenomenon. In the first years of 2000, the Italian Ministry of Transport launched a national project for the definition of thee-amplitude and time of these tidal anomalous waves. The measure of harbors hydrobarometric inverse factors showed a much more intense value than the theoretical one (computed for the offshore). These amplification factors are characteristic of each harbor and can be double (in exceptional cases even more) than offshore. The delay between the arrival times of these tidal waves (induced phenomenon) respect to the time of arrival of the atmospheric pressure variation (inducing phenomenon) depends on 1) morphology of the port basin sea floor and 2) harbor and off-shre water dynamics relationship (first approximation). For these reasons the hydro barometric inverse parameter is not effectiveness computable but it can be determined statistically.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2018YFB1600403)the Natural Science Foundation of Chongqing,China(Grant No.cstc2020jcyj-bshX0043).
文摘Ported wall extensions are important hydraulic structures used to reduce crosscurrents in upper approaches to locks.The effect of such extensions located upstream of a solid guard wall on flow characteristics depends on many factors,including geometric and hydraulic parameters.In this study,the hydraulic performance of ported wall extensions was experimentally investigated in terms of the permeability coefficient,expanding angle,extension length,and flow depth.The results demonstrate that the dimensionless maximum transverse velocity is closely related to the permeability coefficient,expanding angle,and flow depth.By contrast,the dimensionless eddy length mainly depends on the permeability coefficient,expanding angle,and extension length.Furthermore,the optimum permeability coefficient increases with the expanding angle or flow depth,and it is approximately constant for different extension lengths.These results have the potential to provide direct guidance for the design of effective ported wall extensions in upper approaches to locks.
