阅读说明：本技术 一种用于船艏气泡下扫现象测量的方法及装置 (Method and device for measuring bow bubble sweep phenomenon ) 是由 郭春雨 薛嵘 孙聪 胡健 赵大刚 王于 于 2019-11-14 设计创作，主要内容包括：本发明提供一种用于船艏气泡下扫现象测量的方法及装置,拖曳水池的两侧安装拖车轨道,拖车轨道上分别有拖车和辅助小车,造波机安装在拖曳水池一侧,船模和PIV相机通过连接架连接到所述拖车上,PIV相机的镜头对准船模的船艏部位,气泡产生器、浪高仪和PIV激光器安装在所述辅助小车上,PIV激光器对准船模的船艏部位。启动气泡产生器,待微气泡布满拖曳水池表面时停止气泡产生器工作；启动造波机,输入给定试验工况,生成所需波形；当拖车进入匀速段时,PIV系统的PIV相机开始拍摄记录船艏周围气泡场；PIV相机拍摄的照片导入后处理软件中,计算船艏周围气泡绕流场的流场信息。本发明在一定程度上提升了试验的简便性,易于维护,操作简便,使用效率高。(The invention provides a method and a device for measuring the downward sweeping phenomenon of bubbles on a ship bow. Starting the bubble generator, and stopping the bubble generator when micro bubbles are fully distributed on the surface of the towing tank; starting a wave generator, inputting a given test working condition, and generating a required waveform; when the trailer enters a constant-speed section, a PIV camera of the PIV system starts to shoot and record a bubble field around the bow; and (4) importing the pictures shot by the PIV camera into post-processing software, and calculating flow field information of bubbles around the flow field around the bow. The invention improves the test simplicity to a certain extent, is easy to maintain, is simple and convenient to operate and has high use efficiency.)

1. A method for measuring a bow bubble sweep phenomenon is characterized by comprising the following specific implementation steps:

step 1, performing paint spraying treatment on the surface of a bow of a ship model (7);

step 2, trailer tracks (11) are arranged on two sides of the towing tank (1), a trailer and an auxiliary trolley (3) are arranged on the trailer tracks (11), a wave generator (2) is arranged on one side of the towing tank (1), a ship model (7) and a PIV camera (9) are connected to the trailer through a connecting frame (10), a lens of the PIV camera (9) is aligned to the bow part of the ship model (7), a bubble generator (4), a wave height gauge (5) and a PIV laser (6) are arranged on the auxiliary trolley (3), the PIV laser (6) is aligned to the bow part of the ship model (7), and weights are placed in the ship model (7) to enable the draught state and the floating state of the ship model to meet the test requirements;

step 3, calibrating the PIV system by using a calibration device, and debugging a PIV laser (6) of the PIV system;

step 4, starting the bubble generator (4), and stopping the operation of the bubble generator (4) when the micro bubbles are fully distributed on the surface of the towing tank; starting the wave generator (2), inputting a given test working condition, and generating a required waveform;

step 5, starting the trailer, when the trailer enters the constant speed section, starting a PIV camera (9) of the PIV system to shoot and record a bubble field around the bow, and when the trailer reaches the other end of the towing tank (1), starting a brake system and stopping the trailer;

step 6, changing the navigational speed, the wave height wavelength and the size and the thickness of the bubbles in the bubble layer, and repeating the operations from the step 4 to the step 5 until all given test working conditions are completed;

and 7, introducing pictures shot by a PIV camera (9) of the PIV system into post-processing software, and calculating flow field information of bubbles around the flow field around the bow.

2. The utility model provides a device for ship bow bubble is swept phenomenon measurement down, trailer track (11) are installed to the both sides of towing tank (1), have trailer and auxiliary trolley (3) on trailer track (11) respectively, and wave making machine (2) are installed in towing tank (1) one side, its characterized in that: the ship model (7) and the PIV camera (9) are connected to the trailer through a connecting frame (10), a lens of the PIV camera (9) is aligned to the bow part of the ship model (7), the bubble generator (4), the wave height gauge (5) and the PIV laser (6) are installed on the auxiliary trolley (3), and the PIV laser (6) is aligned to the bow part of the ship model (7).

3. The apparatus for measuring bow bubble sweep phenomenon according to claim 2, wherein: and orange-red fluorescent paint is sprayed on the bow part of the ship model (7).

4. The apparatus for measuring bow bubble sweep phenomenon according to claim 2, wherein: the PIV laser (6) can move horizontally on the auxiliary trolley (3).

5. The apparatus for measuring bow bubble sweep phenomenon according to claim 2, wherein: the auxiliary trolley (3), the wave generator (2) and the trailer are respectively connected with a control system of a computer.

Technical Field

The invention belongs to the technical field of ship hydrodynamic tests, and particularly relates to a method and a device for measuring a bow bubble sweep phenomenon.

Background

In a natural state, a part of air is dissolved in seawater due to wave breaking and rain impact, and therefore, a bubble layer exists in seawater near the sea level. In the sailing process of the ship, the interaction between the bow and the waves causes the vortex, so that the bubble layer on the surface of the ocean is sucked under the bow, and the phenomenon of downward sweeping of bubbles is formed. If there are air bubbles below the sonar area at the bottom of the ship, the sound waves may be strongly destroyed (reflected or absorbed). This phenomenon has affected the accuracy of acoustic surveys for many years and remains a significant problem to date. Therefore, the method has great significance for the research of the bubble sweep-down phenomenon. At present, when people test the phenomenon of downward air bubble sweeping, the traditional flow line analysis method is mostly adopted for measurement. Because the bubbles and the streamline have different physical characteristics, the streamline test has larger error, and the phenomenon of downward sweeping of the bubbles cannot be accurately measured. The invention improves the traditional streamline test method, and realizes the measurement of the phenomenon of downward sweeping of bubbles in the pool test by adding the bubbles into the pool.

Disclosure of Invention

The invention aims to provide a method for measuring a bow bubble sweep phenomenon.

The purpose of the invention is realized as follows:

a measuring method for a bow bubble sweep phenomenon comprises the following specific implementation steps:

step 1, performing paint spraying treatment on the surface of a bow of a ship model 7;

step 2, trailer track (11) are installed to the both sides of towing tank (1), have trailer and auxiliary trolley (3) respectively on trailer track (11), and wave generator (2) are installed in towing tank (1) one side, its characterized in that: the ship model (7) and the PIV camera (9) are connected to the trailer through a connecting frame (10), a lens of the PIV camera (9) is aligned to the bow part of the ship model (7), the bubble generator (4), the wave height gauge (5) and the PIV laser (6) are installed on the auxiliary trolley (3), the PIV laser (6) is aligned to the bow part of the ship model (7), and weights are placed in the ship model (7) to enable the draught and floating state of the ship model to meet the test requirements;

step 3, calibrating the PIV system by using a calibration device, and debugging a PIV laser 6 of the PIV system;

step 4, starting the bubble generator 4, and stopping the bubble generator 4 when the micro bubbles are fully distributed on the surface of the towing tank; starting the wave generator 2, inputting a given test working condition, and generating a required waveform;

step 5, starting the trailer, when the trailer enters the constant speed section, starting shooting and recording a bubble field around the bow by a PIV camera 9 of the PIV system, and when the trailer reaches the other end of the towing tank 1, starting a brake system and stopping the trailer;

step 6, changing the navigational speed, the wave height wavelength and the size and the thickness of the bubbles in the bubble layer, and repeating the operations from the step 4 to the step 5 until all given test working conditions are completed;

and 7, importing the pictures shot by the PIV camera 9 of the PIV system into post-processing software, and calculating flow field information of bubbles around the flow field around the bow.

The invention also aims to provide a device for measuring the bow bubble sweep phenomenon.

The purpose of the invention is realized by the following technical scheme:

a measuring device for a bow bubble downward-sweeping phenomenon is characterized in that trailer tracks 11 are arranged on two sides of a towing tank 1, a trailer and an auxiliary trolley 3 are arranged on the trailer tracks 11 respectively, a wave generator 2 is arranged on one side of the towing tank 1, a ship model 7 and a PIV camera 9 are connected to the trailer through a connecting frame 10, a lens of the PIV camera 9 is aligned to the bow part of the ship model 7, a bubble generator 4, a wave height indicator 5 and a PIV laser 6 are arranged on the auxiliary trolley 3, and the PIV laser 6 is aligned to the bow part of the ship model 7.

And orange-red fluorescent paint is sprayed on the bow part of the ship model 7.

The PIV laser 6 can move horizontally on the auxiliary trolley 3.

The auxiliary trolley 3, the wave generator 2 and the trailer are respectively connected with a control system of a computer.

The invention has the beneficial effects that: the invention adopts a water electrolysis mode to generate micro bubbles, and then uses the micro bubbles as tracer particles for PIV measurement; when a PIV camera is used for observing the downward sweeping phenomenon of bubbles on the bow, PIV post-processing software is used for measuring flow field information around the bow; the method can well observe the motion track of the lower scavenging bubble, simultaneously can save the process of particle scattering required by the conventional PIV test, improves the test simplicity to a certain extent, and can be used for researching various motion characteristics of the flow field around the bow of the ship by combining other auxiliary measurement systems; through observation of the lower scavenging bubble group, various characteristics of the micro bubbles in the water can be understood, and the method has important experimental significance; in addition, all related instruments are arranged on the trailer or the auxiliary trolley, so that each module is convenient to operate and easy to maintain, and each part can be conveniently replaced and maintained; has the advantages of simple operation and high use efficiency.

Drawings

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is an overall installation view of all the test devices.

FIG. 3 is a partial enlarged view of the wave generator and the auxiliary trolley.

Fig. 4 is a schematic view of a PIV camera observation ship model.

Detailed Description

The invention is further described with reference to the accompanying drawings in which: