A single-point mooring floating body experimental device and method for a one-way wave pool

Abstract

The present invention discloses a single-point mooring floating body experimental device and method for a one-way wave-making pool. The device comprises a test pool and a ship model in the pool. The side walls of the test pool are fixed with support rods. A pull rope connected to the ship model is suspended by the support rods and a weight is provided at the end of the pull rope. Temporary mooring points are evenly distributed on the side walls of the test pool. Anchor blocks are fixedly provided on the bottom wall of the test pool around the ship model. An inner turret is provided at the bottom of the ship model. Two anchor blocks are provided along the length and width of the ship model, and four anchor blocks are provided between adjacent anchor blocks and are symmetrically distributed around the center of the ship model. A steel wire connected to a mooring cable is provided on the inner turret. A convenient cable replacement structure is connected between the mooring cable and the steel wire. The present invention aims to provide an experimental device and method that can test the motion response of an offshore floating body under the action of multi-directional wind, waves and currents, and realize convenient replacement of the floating body between different mooring conditions.

Description

Technical Field

[0001] The present invention relates to the field of ship and ocean engineering water tank experiments, and in particular to a single-point mooring floating body experimental device and method for a one-way wave-making flow pool. Background Art

[0002] Single-point mooring refers to the fixing of floating objects such as ships or offshore platforms to the seabed through a single-point mooring method. The floating object can rotate 360 ​​degrees with the wind and wave currents. Due to the weather vane effect, the floating object will be moored in the direction with the smallest environmental force, which can extend the service life of the mooring cable and thus ensure that the floating object can work continuously for a long time.

[0003] In order to more accurately study the motion characteristics of a single-point moored float, it is necessary to conduct experiments on the model in a large experimental pool with the ability to simulate environmental loads in multiple directions, that is, equipped with a multi-directional wave generator and flow-generating equipment. However, there are few experimental pools that meet the above conditions. Most existing experimental pools are only capable of generating waves in one direction, which is difficult to meet the experimental needs. In addition, in order to study the motion characteristics and mooring tension of a single-point moored float under different mooring conditions, it is necessary to change the mooring cable and mooring point of the float model in the experiment, which greatly increases the complexity of the experiment compared to a single mooring condition. Moreover, each time the mooring cable is connected to the float, the experimenter needs to calibrate the pre-tension of the mooring cable in the pool. The process of adjusting the mooring cable using conventional techniques is relatively cumbersome. Therefore, changing the mooring condition will greatly affect the experimental progress, and each change of the mooring condition will consume a lot of time. Therefore, there is an urgent need for an experimental device and method that can test the motion response of an offshore float under the action of multi-directional wind, waves and currents in an experimental pool with unidirectional wave generation, and can easily switch between different mooring conditions for various floats. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and to provide an experimental device and method for testing the motion response of an offshore floating body under the action of multi-directional wind, wave and current in an experimental pool with unidirectional wave-generating capability, and for realizing convenient replacement of the floating body between different mooring conditions.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A single-point mooring floating body experimental device for a one-way wave-making pool comprises an experimental pool and a ship model in the pool. Support rods are fixedly provided on the side walls of the experimental pool. A pull rope connected to the ship model is hoisted by the support rods, and a weight is provided at the end of the pull rope. Temporary mooring points are evenly distributed on the side walls of the experimental pool. Anchor blocks are fixedly provided on the bottom wall of the experimental pool around the ship model. An inner turret is provided at the bottom of the ship model. Each anchor block is provided with multiple anchor points for connecting mooring cables to the temporary mooring points and the inner turret. Two anchor blocks are respectively provided along the length and width directions of the hull model, and four anchor blocks are provided between the adjacent anchor blocks and are symmetrically distributed around the center of the hull model; a steel wire connected to the mooring cable is provided on the inner turret, and a tension sensor is provided on the steel wire, and a convenient cable-changing structure is connected between the mooring cable and the steel wire; the convenient cable-changing structure includes a wire locker and a spare cable, one end of the spare cable is connected to the steel wire by a spring buckle, and the other end of the spare cable is passed through the wire locker and connected to the spring buckle at the end of the mooring cable.

[0007] Furthermore, a buoy is provided on the spare cable.

[0008] Furthermore, fixed pulleys are vertically distributed on the support rod, and the pull rope passes around each fixed pulley from bottom to top.

[0009] Also included is a single-point mooring floating body experimental method for a one-way wave pool, comprising the following steps:

[0010] (1) According to the positional relationship between the hull model and the mooring cable under different wave direction conditions, the bow is facing the wave position, all mooring cables, convenient cable replacement structures and their corresponding tension sensors are numbered, and the mooring cables to be used in the experiment are pre-connected between the anchor blocks and the temporary mooring points. Each anchor block is placed at the predetermined position in the experimental pool. The mooring cable located in the length and width direction of the hull model is the In Line condition, and the other four are Between Line conditions.

[0011] (2) The inner turret of the hull model is connected to the tension sensor and the convenient cable replacement structure in sequence using steel wire and spring buckle, so that they correspond one to one;

[0012] (3) Remove the mooring cables under the In Line working condition from the temporary securing points and use spring hooks to connect each mooring cable to the corresponding convenient cable replacement structure on the inner turret according to the number;

[0013] (4) Conduct a tank test on the hull model under conditions simulating wind, wave and current loads. Turn on the wave maker in the experimental tank to simulate the wave loads applied to the hull model, or add weights to the pull rope to simulate the flow load and wind load applied to the hull model. The experimental data are measured by the tension sensors on the steel wires of the inner turret.

[0014] (5) The mooring cable under the In Line working condition is quickly unfastened from the inner turret through the convenient cable-changing structure, and then the mooring cable under the Between Line working condition is connected to the corresponding convenient cable-changing structure on the inner turret. The above steps are repeated to conduct a water tank test under simulated wind, wave and current load conditions.

[0015] Furthermore, in step (3), after each mooring cable connection, the spare cable is stretched or tightened according to the pre-tension of the mooring cable in the hydrostatic state transmitted by the tension sensor, and the length of the spare cable is fixed using a wire lock, and the pre-tension of the mooring cable in this working condition is calibrated by adjusting the overall length of the mooring cable.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention can solve the problem that a one-way wave-making pool test pool is difficult to simulate the motion response of a single-point moored floating body under complex wind, wave and current loads. The present invention can simply and conveniently dismantle the mooring cable and realize the replacement of the mooring working condition. It enriches the test method for simulating single-point moored floating body model tests under complex sea conditions. It can accurately simulate and predict the motion and force of a single-point moored floating body under different wind, wave and current direction combinations, and provide a scientific basis for the design, construction and safe production operation of single-point moored oil and gas equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention;

[0019] Figure 2 is a distribution diagram of anchor blocks and mooring cables in the present invention;

[0020] Figure 3 Schematic diagram of the position of the hull model and mooring cable under the simulated In Line working condition of the present invention;

[0021] Figure 4 Schematic diagram of the position of the hull model and the mooring cable under the Between Line working condition simulated by the present invention;

[0022] Figure 5 Schematic diagram of the convenient cable replacement structure of the present invention;

[0023] Figure 6 Schematic diagram of the pull rope and hull model when simulating wind, wave and current loads in different directions according to the present invention;

[0024] Figure 7 It is a flowchart of the experimental process of the present invention.

[0025] Reference numerals:

[0026] 1- Experimental pool, 2- Temporary mooring point, 3- Anchor block, 4- Mooring cable, 5- Hull model, 6- Inner turret, 7- Convenient cable replacement structure, 8- Tension sensor, 9- Pull rope, 10- Fixed pulley, 11- Support rod, 12- Weight, 71- Line locker, 72- Spare cable, 73- Buoy, 74- Spring buckle. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0028] like Figures 1 to 6 As shown, a single-point mooring floating body experimental device for a one-way wave-making pool includes an experimental pool 1 and a hull model 5 in the pool. The side walls of the experimental pool 1 are fixedly provided with support rods 11. A pull rope 9 connected to the hull model 5 is hoisted by the support rods 11, and a weight 12 is provided at the end of the pull rope 9. Temporary mooring points 2 are evenly distributed on the side walls of the experimental pool 1. Anchor blocks 3 are fixedly provided on the bottom wall of the experimental pool 1 around the hull model 5. An inner turret 6 is provided at the bottom of the hull model 5. Each anchor block 3 is provided with multiple anchor points for connecting a mooring line 4 between the temporary mooring points 2 and the inner turret 6. Two anchor blocks 3 are respectively provided along the length and width directions of the hull model 5, and four anchor blocks 3 are provided between the adjacent anchor blocks 3 and are symmetrically distributed around the center of the hull model 5; a steel wire connected to the mooring cable 4 is provided on the inner turret 6, and a tension sensor 8 is provided on the steel wire, and a convenient cable-changing structure 7 is connected between the mooring cable 4 and the steel wire; the convenient cable-changing structure 7 includes a wire locker 71 and a spare cable 72, one end of the spare cable 72 is connected to the steel wire by a spring buckle 74, and the other end of the spare cable 72 is passed through the wire locker 71 and is connected to the spring buckle 74 at the end of the mooring cable 4.

[0029] The spare cables 72 are provided with buoys 73 to facilitate recording the positions of the spare cables 72 during the experiment and facilitate experimental observation.

[0030] The support rod 11 is vertically provided with fixed pulleys 10, and the pull rope 9 is passed through each fixed pulley 10 from bottom to top. The fixed pulleys 10 can smoothly pull the pull rope 9 to the top of the support rod 11, making it convenient to connect a weight 12 to the end of the pull rope 9. The tension exerted by the weight 12 on the pull rope 9 simulates wind, wave and current loads.

[0031] like Figure 7 As shown, the experimental method steps of the present invention are as follows:

[0032] (1) According to the positional relationship between the hull model 5 and the mooring cables 4 under different wave direction conditions, the bow of the ship is facing the wave position. All mooring cables 4, convenient cable replacement structures 7, and their corresponding tension sensors 8 are numbered. The mooring cables 4 to be used in the experiment are pre-connected between the anchor blocks 3 and the temporary mooring points 2. Each anchor block 3 is placed in a predetermined position in the experimental pool 1. The mooring cables 4 located in the length and width direction of the hull model 5 are in the In Line working condition, and the remaining four are in the Between Line working condition. In this embodiment, each anchor block 3 has four mooring cables 4, for a total of 32 mooring cables.

[0033] (2) The inner turret 6 of the hull model 5 is connected to the tension sensor 8 and the convenient cable replacement structure 7 in sequence using steel wires and spring hooks 74, so that they correspond one to another. The hull model 5 and the inner turret 6 can be designed and constructed in accordance with the upper assembly 4 and the inner turret model 5 disclosed in the utility model patent application number 2021222677698, an inner turret device suitable for FPSO tank model testing.

[0034] (3) If Figure 3 As shown, in the In Line condition, the mooring cables 4 are removed from the temporary anchoring points 2. Each mooring cable 4 is connected, according to its number, to the corresponding convenient cable-changing structure 7 on the inner turret 6 using a spring hook 74. Tension sensors 8 are installed on each steel wire connecting the mooring cables 4 to the inner turret 6, and a data transmission line is pre-set. After each mooring cable 4 connection, the standby cable 72 is stretched or tightened based on the hydrostatic pretension measured by the tension sensors 8. The length of the standby cable 72 is then fixed using a wire lock 71. The mooring pretension for that condition is calibrated by adjusting the overall length of the mooring cables 4.

[0035] (4) A water tank test is conducted on the hull model 5 under conditions simulating wind, wave and current loads. The wave maker of the experimental water tank is turned on to simulate the wave load applied to the hull model 5, or a weight 12 is applied to the pull rope 9 to simulate the flow load and wind load applied to the hull model 5. The experimental data are measured by the tension sensors 8 on the steel wires of the inner turret 6.

[0036] (5) If Figure 4 As shown, the mooring cable 4 in the In Line working condition is quickly unfastened from the inner turret 6 through the convenient cable-changing structure 7, and then the mooring cable 4 in the Between Line working condition is connected to the corresponding convenient cable-changing structure 7 on the inner turret 6. The above steps are repeated to conduct a water tank test under simulated wind, wave and current load conditions.

[0037] like Figure 6 As shown, when the directions of the simulated wind, wave and current loads are different, the experimental water pool 1 can be correspondingly increased with support rods 11 and fixed pulleys 10 , thereby connecting multiple pull ropes 9 to the hull model 5 .

[0038] The method and calculation formula for equivalent simulation of wind, wave and current loads can be calculated according to the formula disclosed in the invention patent application number 2021111132644, "An Equivalent Simulation Method for Flow Loads on a Single Point Mooring System in a Wind and Wave Environment." When simulating a floating body subjected to steady wind loads, the principles, components, and experimental setup of the equivalent wind load simulation device are the same as those for the equivalent flow load simulation device.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A single-point mooring floating body experimental device for a one-way wave-making pool, comprising an experimental pool (1) and a hull model (5) in the pool, characterized in that: The side wall of the experimental water tank (1) is fixedly provided with a support rod (11), a pull rope (9) connected to the hull model (5) is lifted by the support rod (11) and a weight (12) is provided at the end of the pull rope (9), and temporary fastening points (2) are evenly distributed on the side wall of the experimental water tank (1), and anchor blocks (3) are fixedly provided around the hull model (5) on the bottom wall of the experimental water tank (1), and an inner rotating tower (6) is provided at the bottom of the hull model (5), and each anchor block (3) is provided with a plurality of anchor points for connecting the mooring cable (4) between the temporary fastening point (2) and the inner rotating tower (6); the anchor blocks (3) are respectively arranged along the length direction and the length direction of the hull model (5) Two anchor blocks (3) are provided in the width direction, and four anchor blocks (3) are provided between the adjacent anchor blocks (3) and are symmetrically distributed around the center of the hull model (5); a steel wire connected to the mooring cable (4) is provided on the inner turret (6), and a tension sensor (8) is provided on the steel wire. A convenient cable-changing structure (7) is connected between the mooring cable (4) and the steel wire; the convenient cable-changing structure (7) includes a wire lock (71) and a spare cable (72), one end of the spare cable (72) is connected to the steel wire through a spring buckle (74), and the other end of the spare cable (72) is passed through the wire lock (71) and is connected to the spring buckle (74) at the end of the mooring cable (4).

2. The single-point mooring floating body experimental device for a one-way wave pool according to claim 1, characterized in that: A buoy (73) is provided on the spare cable (72).

3. The single-point mooring floating body experimental device for a one-way wave pool according to claim 1, characterized in that: Fixed pulleys (10) are vertically distributed on the support rod (11), and the pull rope (9) passes around each fixed pulley (10) from bottom to top.

4. A method for testing a single-point mooring float for a one-way wave-making pool, based on the single-point mooring float testing device for a one-way wave-making pool according to any one of claims 1 to 3, characterized in that: Here are the steps: (1) According to the positional relationship between the hull model (5) and the mooring cable (4) under different wave direction conditions, the bow is directed toward the wave-facing position, all the mooring cables (4), the convenient cable replacement structure (7) and their corresponding tension sensors (8) are numbered, and the mooring cables (4) to be used in the experiment are pre-connected between the anchor block (3) and the temporary mooring point (2), and each anchor block (3) is placed at a predetermined position in the experimental pool (1). The mooring cable (4) located in the length and width direction of the hull model (5) is the In Line working condition, and the other four are Between Line working conditions; (2) The inner turret (6) of the hull model (5) is connected to the tension sensor (8) and the convenient cable replacement structure (7) in sequence using steel wire and spring buckle (74) so ​​that they correspond one to another; (3) Remove the mooring cables (4) under the In Line working condition from the temporary fastening point (2), and use the spring buckle (74) to connect each mooring cable (4) to the corresponding convenient cable replacement structure (7) on the inner turret (6) according to the number; (4) Conducting a water tank test on the hull model (5) under conditions simulating wind, wave and current loads, turning on the wave maker of the experimental water tank to simulate the wave load applied to the hull model (5), or adding weights (12) to the pull rope (9) to simulate the flow load and wind load applied to the hull model (5), and measuring the experimental data through the tension sensors (8) on each steel wire of the inner turret (6); (5) The mooring cable (4) under the In Line working condition is quickly unfastened from the inner rotating tower (6) through the convenient cable-changing structure (7), and then the mooring cable (4) under the Between Line working condition is connected to the corresponding convenient cable-changing structure (7) on the inner rotating tower (6). The above steps are repeated to conduct a water tank test under the simulated wind, wave and current load conditions.

5. The single-point mooring floating body experimental method for a one-way wave-making pool according to claim 4, characterized in that: In step (3), after each connection of the mooring cable (4), the spare cable (72) is stretched or tightened according to the pre-tension of the mooring cable in the hydrostatic state transmitted by the tension sensor (8), and the length of the spare cable (72) is fixed using the wire lock (71), and the pre-tension of the mooring cable in the working condition is calibrated by adjusting the overall length of the mooring cable (4).

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