A method and system for analyzing the wake of a ship in a navigable tunnel on the safety of navigation

Abstract

The application provides a method and system for analyzing the wake of a ship in a navigation tunnel and affecting the safety of navigation, and belongs to the technical field of shipping safety. First, basic data for analyzing the wake of the ship in the navigation tunnel are obtained, then an initial wave height of the ship wake is calculated based on the running speed, the width of the ship and the draft, a navigation tunnel influence factor is calculated based on the section diameter and the width of the ship, and a kelvin wake term KT is calculated based on the section diameter and the width of the ship; finally, a final wave height of the ship wake is calculated based on the initial wave height of the ship wake, the navigation tunnel influence factor and the kelvin wake term, and the safety of navigation is analyzed. In the calculation of the wave height of the ship wake, the section of the navigation tunnel and the ship type are comprehensively considered, and compared with the prior art, the physical analysis model completeness of the wave height of the ship wake in the navigation tunnel is improved, and the accuracy of the analysis result of the wave height is improved objectively.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of shipping safety, and particularly relates to a method and system for analyzing the influence of ship wake in a navigation tunnel on navigation safety. BACKGROUND

[0002] A navigation tunnel is an engineering facility used for crossing mountains or complex terrain in shipping, which can shorten the voyage and meet the shipping requirements of high-fall terrain. However, the high wave wake and bubbles formed by the navigation ship running in the navigation tunnel will inevitably change the local flow state of the tunnel, leading to difficult operation of the subsequent ship and easy collision in the narrow tunnel. Therefore, it is necessary to analyze the ship wake in the navigation tunnel, especially the wave height of the ship wake in the navigation tunnel, to ensure the safe running of the ship in the navigation tunnel. In the prior art, the influence of the cross section of the navigation tunnel and the ship type on the wave height of the ship wake is ignored, resulting in an incomplete physical analysis model of the wave height of the ship wake in the navigation tunnel and inaccurate analysis results. SUMMARY

[0003] In order to solve the above problems existing in the prior art, the present application provides a method and system for analyzing the influence of ship wake in a navigation tunnel on navigation safety, which can improve the accuracy of the analysis results of the wave height of the ship in the navigation tunnel.

[0004] In order to achieve the above purpose, the present application adopts the following technical scheme: a method for analyzing the influence of ship wake in a navigation tunnel on navigation safety, comprising the following steps: step S1: obtaining the average water depth h and the cross section diameter D in the navigation tunnel; real-time monitoring the ship length L, the ship waterline length LL, the ship width B, the draft T, the displacement CUB and the running speed V in the navigation tunnel; step S2: calculating the initial ship wake wave height H0 based on the running speed V, the ship width B and the draft T; step S3: calculating the navigation tunnel influence factor TUN based on the cross section diameter D and the ship width B; step S4: calculating the kelvin wake term KT according to the ship length L and the ship width B; step S5: calculating the final ship wake wave height based on the initial ship wake wave height H0, the navigation tunnel influence factor TUN and the kelvin wake term KT, and performing the safety level analysis of the following ship navigation according to the final ship wake wave height; the initial ship wake wave height H0, the navigation tunnel influence factor TUN and the kelvin wake term KT are multiplied to obtain the final ship wake wave height in step S5; when the final ship wake wave height is greater than or equal to the preset wave height reference value, it is determined that the safety level of the following ship navigation is high risk, and when the final ship wake wave height is less than the preset wave height reference value, it is determined that the safety level of the following ship navigation is low risk.

[0005] Further, the step S2 calculates the initial ship wake wave height H0, specifically: step S21: calculate the ratio of the average water depth h in the navigation tunnel to the ship length L, denoted as K1; step S22: determine whether K1 is less than a first preset threshold, when K1 is less than the first preset threshold, the first formula is used to calculate the initial ship wake wave height H0; when K1 is not less than the first preset threshold, step S23 is executed; step S23: determine whether K1 is less than a second preset threshold, when K1 is less than the second preset threshold, the second formula is used to calculate the initial ship wake wave height H0; otherwise, the third formula is used to calculate the initial ship wake wave height H0.

[0006] Further, the first formula in the step S22 is:

[0007] ;

[0008] Wherein H0 represents the initial ship wake wave height, A1 represents the first adjustment coefficient, V represents the ship speed in the navigation tunnel, g represents the acceleration of gravity, B represents the ship width in the navigation tunnel, T represents the ship draft in the navigation tunnel, and ST represents the ship type correction coefficient.

[0009] The second formula in the step S23 is:

[0010] ;

[0011] Wherein A2 represents the second adjustment coefficient.

[0012] The third formula in the step S23 is:

[0013] ;

[0014] Wherein A3 represents the third adjustment coefficient.

[0015] Further, the step S3 calculates the navigation tunnel influence factor, specifically:

[0016] ;

[0017] Wherein TUN represents the navigation tunnel influence factor, and A4 represents the fourth adjustment coefficient.

[0018] Further, the step S4 of calculating the Kelvin wake term KT specifically comprises the following steps: step S41: defining a ship type coefficient SF, calculating a ratio of the displacement volume CUB and a ship coefficient, denoted as K2; the ship coefficient is a product of the ship waterline length LL, the draught T and the ship width B; step S42: judging whether K2 is less than a third preset threshold value, when K2 is less than the third preset threshold value, assigning SF as a first value; otherwise, executing step S43; step S43: judging whether K2 is less than a fourth preset threshold value, when K2 is less than the fourth preset threshold value, assigning SF as a second value; otherwise, assigning SF as a third value; step S44: generating 1000 equidistant angle values from negative pi / 2 to positive pi / 2 by using a linspace function, defining the angle value number as i, for each angle value θi i , calculating the degree value θi based on the following formula: i The corresponding integral element IGi i :

[0019] ;

[0020] Step S45: calculating the Kelvin wake term KT based on the integral element IGi:

[0021] ;

[0022] Wherein, trapz() represents a numerical integration function.

[0023] The application further provides a ship wake in a navigation tunnel affecting navigation safety analysis system for executing the ship wake in the navigation tunnel affecting navigation safety analysis method, the ship wake in the navigation tunnel affecting navigation safety analysis system comprising a data acquisition unit, a navigation safety level analysis unit and an analysis result output unit, the data acquisition unit being connected with the navigation safety level analysis unit, and the navigation safety level analysis unit being connected with the analysis result output unit.

[0024] The application has the beneficial technical effects compared with the prior art that the navigation tunnel section and the ship type are comprehensively considered when calculating the ship wake wave height, the physical analysis model completeness of the ship wake wave height in the navigation tunnel is improved compared with the prior art, and the wave height analysis result accuracy is improved objectively. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can also be obtained according to the provided drawings without creative labor.

[0026] Figure 1 Flowchart of the method for analyzing the wake of a ship in a navigation tunnel on the navigation safety in the application;

[0027] Figure 2 Flowchart of the method for calculating the initial ship wake wave height H0 in the application;

[0028] Figure 3 Flowchart of the method for calculating the Kelvin wake term KT in the application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the application will be apparently and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0030] The concepts involved in the application will be described below in combination with the drawings. It should be noted that the following descriptions of the concepts are only for the purpose of making the content of the application easier to understand, and do not represent the limitation on the protection scope of the application. Meanwhile, the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0031] The drawings in the specification Figure 1The application relates to an analysis method for the tail flow of a ship in a navigation tunnel and the influence of the tail flow on navigation safety, which comprises the following steps: step S1: obtaining the average water depth h and the section diameter D in the navigation tunnel; real-time monitoring of the ship length L, the ship waterline length LL, the ship width B, the draught T, the displacement CUB and the running speed V in the navigation tunnel; the above variables are basic data for analyzing the tail flow of the ship in the navigation tunnel, which can be measured in real time through sensors or can be corresponding simulation parameters obtained when the ship is simulated to sail in the navigation tunnel; step S2: calculating the initial ship tail flow wave height H0 based on the running speed V, the ship width B and the draught T; step S3: calculating the navigation tunnel influence factor TUN based on the section diameter D and the ship width B; step S4: calculating the kelvin tail flow term KT according to the ship length L and the ship width B; step S5: multiplying the H0, TUN and KT to obtain the final ship tail flow wave height based on the initial ship tail flow wave height H0, the navigation tunnel influence factor TUN and the kelvin tail flow term KT, and performing the navigation safety level analysis of the following ship according to the final ship tail flow wave height; when the final ship tail flow wave height is greater than or equal to the preset wave height reference value, the navigation safety level of the following ship is determined as high risk; when the final ship tail flow wave height is less than the preset wave height reference value, the navigation safety level of the following ship is determined as low risk; it can be understood that a plurality of preset wave height reference values can be set, and different navigation safety levels of the following ship correspond to different final ship tail flow wave heights between different preset wave height reference values.

[0032] The application is illustrated by the accompanying drawings Figure 2 In the step S2, the initial ship tail flow wave height H0 is calculated, and the calculation specifically comprises the following sub-steps: step S21: calculating the ratio of the average water depth h in the navigation tunnel to the ship length L, denoted as K1, to determine the water depth condition of the specific ship in the water area in the navigation tunnel; step S22: determining whether K1 is less than a first preset threshold (0.3 in the simulation code program of the application, as the determination threshold of the shallow water area); when K1 is less than the first preset threshold, the first formula is used to calculate the initial ship tail flow wave height H0; when K1 is not less than the first preset threshold, step S23 is performed; step S23: determining whether K1 is less than a second preset threshold (0.5, as the determination threshold of the medium water depth area); when K1 is less than the second preset threshold, the second formula is used to calculate the initial ship tail flow wave height H0; otherwise, that is, when K1 is greater than or equal to the second preset threshold (at this time, the condition of the deep water area is determined), the third formula is used to calculate the initial ship tail flow wave height H0.

[0033] The first formula in the step S22 is:

[0034] ;

[0035] Wherein H0 represents the initial ship wake wave height, A1 represents the first adjustment coefficient (which can be taken as 0.28), V represents the ship running speed in the navigation tunnel, g represents the gravity acceleration, B represents the ship width in the navigation tunnel, T represents the ship draft in the navigation tunnel, and ST represents the ship type correction coefficient.

[0036] The second formula in the step S23 is:

[0037] ;

[0038] Wherein A2 represents the second adjustment coefficient (which can be taken as 0.25).

[0039] The third formula in the step S23 is:

[0040] ;

[0041] Wherein A3 represents the third adjustment coefficient (which can be taken as 0.2).

[0042] Through the above ratio of the average water depth h and the ship length L and the calculation mode selected according to the ratio, the sinking amount of the ship body in the navigation tunnel can be simulated more accurately, and the calculation accuracy of the wake wave height is improved. The first adjustment coefficient A1, the second adjustment coefficient A2 and the third adjustment coefficient A3 respectively represent the ship wake wave height empirical coefficient under different water depth conditions, which is used to reflect the concentration degree of wave energy under different water depth conditions.

[0043] The navigation tunnel influence factor is calculated in the step S3, which is specifically:

[0044] ;

[0045] Wherein TUN represents the navigation tunnel influence factor, and A4 represents the fourth adjustment coefficient (which can be taken as 0.85). By setting the navigation tunnel influence factor, the enhancement or superposition effect of the tunnel diameter on the wave height can be reflected, so that the above physical model is more complete. The fourth adjustment coefficient A4 is an empirical proportion coefficient for adjusting the influence strength of the ratio of the tunnel width B and the water depth D on the tunnel constraint effect.

[0046] The accompanying drawings are combined with the specification Figure 3, the step S4 of calculating the Kelvin wake term KT specifically comprises the following steps: a step S41 of defining a ship type coefficient SF, calculating a ratio of the displacement volume CUB and a ship coefficient, denoted as K2; the ship coefficient is a product of the ship waterline length LL, the draught T and the ship width B; a step S42 of judging whether K2 is less than a third preset threshold (which can be 0.6), when K2 is less than the third preset threshold, assigning SF as a first value; otherwise, executing a step S43; the step S43 of judging whether K2 is less than a fourth preset threshold (which can be 0.8), when K2 is less than the fourth preset threshold, assigning SF as a second value; otherwise, assigning SF as a third value; the first value is less than the second value, and the second value is less than the third value. The third preset threshold and the fourth preset threshold are used to divide the ship body of the navigation ship in the navigation tunnel into three types of conventional, small and large ship bodies, so as to distinguish the fluid dynamic characteristic differences of different ship types or ship bodies; a step S44 of generating 1000 equidistant angle values from negative π / 2 to positive π / 2 by using a linspace function (used to generate a uniformly distributed numerical sequence in a specified interval), defining the angle value number as i, for each angle value θ i , the degree value θ i is calculated based on the following formula: i

[0047] ;

[0048] The former half of the multiplication sign in the above formula is used to calculate the wave attenuation caused by the inner wall of the navigation tunnel, and the latter half of the multiplication sign simulates the interaction between the wave and the ship body, which is used to analyze the wave interference phenomenon of the ship in the navigation tunnel, and it needs to be noted that the multiplication sign can represent the vector dot product operation in the simulation program code.

[0049] A step S45 of calculating the Kelvin wake term KT based on the integral element IG i :

[0050] ;

[0051] Wherein, trapz() represents a numerical integration function, and the trapz() function can calculate the definite integral approximation value of discrete data based on the trapezoidal rule.

[0052] ​The application further provides a ship wake in a navigation tunnel analysis system for analyzing the influence of ship wake on navigation safety, which is used for executing the ship wake in a navigation tunnel analysis method. The ship wake in a navigation tunnel analysis system comprises a data acquisition unit, a navigation safety level analysis unit and an analysis result output unit. The data acquisition unit is connected with the navigation safety level analysis unit. The navigation safety level analysis unit is connected with the analysis result output unit. The data acquisition unit is used for acquiring basic data for ship wake analysis in a navigation tunnel, which comprises but is not limited to a plurality of sensors, a range finder, a CCD camera, a video transmission line, a video distributor, a video capture card, a rudder angle measuring instrument and a computer equipped with a ship model real-time measurement system and the like. The navigation safety level analysis unit is used for calculating the final ship wake wave height and performing navigation safety level analysis. The analysis result output unit is used for outputting the analysis result, so that different ship scheduling strategies are executed when subsequent ships navigate, for example, when the navigation safety level of a rear ship is determined to be high risk, the rear ship should be switched to a radar ARPA mode to dynamically monitor the distance from a front ship and perform a speed gradient management strategy. If necessary, a warning is issued to make the rear ship anchor and wait. When the navigation safety level of the rear ship is determined to be low risk, a sufficient safety distance (for example, 3 times the length of the front ship) is maintained from the front ship and the speed is reduced (at least less than 8 knots), which is recorded as a navigation log. Of course, a visual tool can also be used to display the relative position of the ship, and arrows and the like are used to mark the potential collision position and collision probability, and Dijkstra algorithm and the like are used to generate a possible avoidance path of the rear ship.

[0053] The ship wake in a navigation tunnel analysis system can improve the ship navigation management efficiency, scientifically allocate the navigation tunnel resources, intelligently realize the ship collision risk prevention and control to ensure the navigation safety. Meanwhile, the ship wake in a navigation tunnel analysis system provides reference data for the construction and optimization of the navigation tunnel.

[0054] The above-described embodiments and / or implementations are only used to illustrate the preferred embodiments and / or implementations of the present application, and do not limit the embodiments of the present application in any form. Any person skilled in the art can make some changes or modifications to other equivalent embodiments without departing from the technical means disclosed in the present application, but the changes or modifications should be regarded as the same technology or embodiment as the present application.

[0055] The principles and implementation manners of the present application are described herein by using specific examples, and the above example descriptions are only used to help understand the method of the present application and its core idea. The above descriptions are only preferred embodiments of the present application, and it should be pointed out that, due to the limited nature of the language expression, there are objectively infinite specific structures, and for ordinary skilled persons in the technical field, some improvements, refinements or changes can be made without departing from the principles of the present application, and the above technical features can also be combined in an appropriate manner; these improvements, refinements, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, shall be regarded as the protection scope of the present application.

Claims

1. A method of analyzing the effect of ship wake in a navigable tunnel on navigational safety, characterized in that, The method comprises the following steps: Step S1: obtaining the average water depth h and the cross-sectional diameter D in the navigation tunnel; and real-time monitoring the ship length L, the ship waterline length LL, the ship width B, the draft T, the displacement CUB and the running speed V in the navigation tunnel; Step S2: calculating the initial ship wake wave height H0 based on the running speed V, the ship width B and the draft T; Step S3: calculating the navigation tunnel influence factor TUN based on the cross-sectional diameter D and the ship width B; Step S4: calculating the kelvin wake term KT according to the ship length L and the ship width B; Step S5: calculating the final ship wake wave height based on the initial ship wake wave height H0, the navigation tunnel influence factor TUN and the kelvin wake term KT, and performing the following-ship navigation safety level analysis according to the final ship wake wave height; The initial ship wake wave height H0, the navigation tunnel influence factor TUN and the kelvin wake term KT are multiplied to obtain the final ship wake wave height in the step S5; When the final ship wake wave height is greater than or equal to a preset wave height reference value, it is determined that the following-ship navigation safety level is high risk; and when the final ship wake wave height is less than the preset wave height reference value, it is determined that the following-ship navigation safety level is low risk.

2. The method of claim 1, wherein the method is characterized by: The initial ship wake wave height H0 is calculated in the step S2, and specifically: Step S21: calculating the ratio of the average water depth h to the ship length L, denoted as K1; Step S22: determining whether K1 is less than a first preset threshold value; when K1 is less than the first preset threshold value, the initial ship wake wave height H0 is calculated by using a first formula; When K1 is not less than the first preset threshold value, step S23 is performed; Step S23: determining whether K1 is less than a second preset threshold value; when K1 is less than the second preset threshold value, the initial ship wake wave height H0 is calculated by using a second formula; Otherwise, the initial ship wake wave height H0 is calculated by using a third formula.

3. The method of claim 2, wherein the method is characterized by: The first formula in the step S22 is: ； wherein H0 represents the initial ship wake wave height, A1 represents a first adjustment coefficient, V represents the ship running speed in the navigation tunnel, g represents the gravitational acceleration, B represents the ship width in the navigation tunnel, T represents the ship draft in the navigation tunnel, and ST represents a ship type correction coefficient.

4. The method of claim 3, wherein the method is characterized by: The second formula in the step S23 is: ； wherein A2 represents a second adjustment coefficient.

5. A method of analyzing the wake of a vessel in a navigable tunnel on navigational safety according to claim 4, characterized in that, The third formula in the step S23 is: ； wherein A3 represents a third adjustment coefficient.

6. The method of claim 1, wherein the method is characterized by: The navigation tunnel influence factor is calculated in the step S3, and specifically: ； wherein TUN represents the navigation tunnel influence factor, and A4 represents a fourth adjustment coefficient.

7. The method of claim 2, wherein the method is characterized by: The kelvin wake term KT is calculated in the step S4, and specifically includes the following steps: Step S41: defining a ship type coefficient SF, calculating the ratio of the displacement CUB to a ship coefficient, denoted as K2; the ship coefficient is the product of the ship waterline length LL, the draft T and the ship width B; Step S42: determining whether K2 is less than a third preset threshold value; when K2 is less than the third preset threshold value, SF is assigned a first value; Otherwise, step S43 is performed; Step S43: judging whether K2 is less than a fourth preset threshold value, and assigning SF as a second value when K2 is less than the fourth preset threshold value; Otherwise, assigning SF as a third value; Step S44: Generate 1000 equidistant angle values from negative π / 2 to positive π / 2 using linspace function, define the angle value as θi, for each angle value θi i , calculate the angle value θi based on the following formula i The corresponding integral element IGi i : ； Step S45: Based on the integral element IG i Compute Kelvin wake term KT: ； Wherein, trapz() represents a numerical integration function.

8. A system for analyzing the effect of ship wake in a navigable tunnel on the safety of navigation, for performing a method of analyzing the effect of ship wake in a navigable tunnel on the safety of navigation according to any one of claims 1 to 7, characterized in that, The system for analyzing the wake of a ship in a navigable tunnel on the safety of navigation comprises a data acquisition unit, a navigation safety level analysis unit and an analysis result output unit, the data acquisition unit is connected with the navigation safety level analysis unit, and the navigation safety level analysis unit is connected with the analysis result output unit.

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