阅读说明：本技术 一种适用于超低流速条件下的走航式adcp河流流量测验方法 (Walking type ADCP river flow testing method suitable for ultralow flow speed condition ) 是由 梅军亚 周波 赵昕 张莉 陈超 胡立 张生稳 于 2020-06-30 设计创作，主要内容包括：本发明公开了一种适用于超低流速条件下的走航式ADCP河流流量测验方法,包括：布设多条垂线,每条垂线上布设多个测点；将ADCP从断面的一岸运行至另一岸,记录岸别,并采用正常船速运行至相应垂线处开始测流；测船停在每条测速垂线,通过ADCP直接测量垂线的平均流速,并记录测速开始、结束时间；利用流速面积法计算断面流量。本发明的走停法ADCP流量测验方法采用1次测流即可完成流量测验,工作量小,精度可靠；可解决在超低流速条件下采用走航式ADCP测流工作量大、精度不高的技术难题,为超低流速下河流流量的测验提供解决方案。(The invention discloses a sailing type ADCP river flow testing method suitable for an ultralow flow speed condition, which comprises the following steps: laying a plurality of vertical lines, and laying a plurality of measuring points on each vertical line; the method comprises the following steps of (1) running the ADCP from one bank to the other bank of a section, recording the bank difference, and starting flow measurement when the ADCP runs to a corresponding vertical line at a normal ship speed; the ship is stopped at each speed measuring vertical line, the average flow speed of the vertical line is directly measured through the ADCP, and the starting time and the ending time of the speed measurement are recorded; and calculating the cross-section flow by using a flow velocity area method. The ADCP flow test method adopting the stop-and-go method can complete the flow test by adopting 1-time flow measurement, and has small workload and reliable precision; the technical problems of large workload and low precision of the sailing ADCP flow measurement under the condition of the ultra-low flow velocity can be solved, and a solution is provided for the river flow test under the ultra-low flow velocity.)

1. A method for testing river flow of an aerial ADCP (advanced digital content control channel) suitable for an ultralow flow speed condition is characterized by comprising the following steps:

laying a plurality of vertical lines, and laying a plurality of measuring points on each vertical line;

the method comprises the following steps of (1) running the ADCP from one bank to the other bank of a section, recording the bank difference, and starting flow measurement when the ADCP runs to a corresponding vertical line at a normal ship speed;

the ship is stopped at the speed measurement vertical line, the average flow velocity of the vertical line is directly measured through the ADCP, and the start time and the end time of the speed measurement are recorded;

and calculating the cross-section flow by using a flow velocity area method.

2. The marching type ADCP river discharge testing method according to claim 1, wherein the number m of speed measuring vertical lines is selected according to the requirements of river discharge testing regulations, and each vertical line is tested for Δ t.

3. The method for navigable ADCP river traffic testing according to claim 2, wherein the time period between the start and end times of the speed measurement is not less than the required testing duration Δ t.

4. The navigable ADCP river discharge test method of claim 2, further comprising:

repeating the steps to complete the measurement of the flow velocity of the m vertical lines on the section;

and extracting the flow velocity of each vertical line from the ADCP flow measurement data file, averaging the flow velocity of the test period to be used as the average flow velocity of the vertical lines, and calculating the section flow by using a flow velocity area method.

Technical Field

The invention relates to the technical field of river flow testing, in particular to a sailing type ADCP river flow testing method suitable for an ultralow flow speed condition.

Background

River flow is one of the most important elements of hydrology, and with the progress of technology, the underway ADCP (acoustic doppler current profiler) method has become one of the main means of hydrology traffic testing. The method has the advantages of high automation level and strong timeliness.

In order to ensure the test precision, the ship speed V needs to be adjusted in the test process_bAverage velocity V of water flow_W(hereinafter referred to as ship speed ratio)) The accuracy is higher when the ship speed is lower than the flow speed. The current technical standard acoustic doppler flow testing specification (SL337-2006) stipulates that 2 round-trip measurements (4 times in total) should be carried out for ADCP flow measurement, when the relative error of the mean value of each single flow and 4 flows is not more than 5%, the mean value is taken as a test result, and if the requirement is not met, the measurement should be retested.

In water bodies with great water depth and small flow speed, such as reservoir areas and the like, the traditional mechanical type flow velocity meter cannot be used due to the factors that the flow velocity is too low to reach the starting flow velocity, or the flow velocity and the flow direction of a vertical line are complex in distribution, and the like, and the technical difficulty can be overcome by using an ADCP flow measurement technology. However, because the water flow is very slow and the flow state is very complex, the ADCP result of each flow measurement is unstable and the variation is very large. In order to meet the requirement that the relative error between 4 single flows and the average flow specified in acoustic Doppler flow test Specification (SL337-2006) is not more than 5%, hydrologic testers need to repeatedly measure the flow (hereinafter referred to as a repeated flow measurement method) on the same cross section, adopt a trial-and-error method to select 4 flows meeting the precision requirement in multiple flow measurement results, and use the average value of the selected 4 flows as the flow measurement result.

The repeated flow measurement method has two disadvantages:

1. the workload is very large: because the repeated flow measurement method needs to test the section repeatedly, a large amount of time is consumed; for example, for a cross section with the width of 200 meters, the flow measurement only needs 1 hour under the condition of normal water flow; and a repeated flow measurement method is adopted, the flow measurement time is 3-4 hours, and the longest time is 8 hours.

2. The precision is unreliable: the ADCP flow theoretically requires that the ship speed ratio k is less than or equal to 1, the ship speed is generally greater than the flow speed in practical application, and the ship speed is difficult to be smaller than the flow speed completely, but the ship speed ratio is controlled within a certain range, and engineering application shows that the flow measurement precision can meet the requirement when k is less than or equal to 5. When the flow velocity is ultra-low (the flow velocity is 0.002-0.005 m/s), and the ship speed is controlled to be 0.1m/s, the ship speed ratio k is 20-50, so that the requirement that k is less than or equal to 5 can not be met, and the requirement that k is less than or equal to 1 can not be met, the uncertainty of ADCP flow measurement is very high, and the flow measurement precision can not meet the standard requirement. Therefore, even if 4 flows are picked to meet the accuracy requirement, the accuracy is inherently unreliable.

In summary, it is very difficult to perform river discharge tests at ultra low flow rates using the prior art.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a sailing type ADCP river flow testing method suitable for the condition of ultralow flow rate.

The invention discloses a sailing type ADCP river flow testing method suitable for an ultralow flow speed condition, which comprises the following steps:

laying a plurality of vertical lines, and laying a plurality of measuring points on each vertical line;

the method comprises the following steps of (1) running the ADCP from one bank to the other bank of a section, recording the bank difference, and starting flow measurement when the ADCP runs to a corresponding vertical line at a normal ship speed;

the ship is stopped at the speed measurement vertical line, the average flow velocity of the vertical line is directly measured through the ADCP, and the start time and the end time of the speed measurement are recorded;

and calculating the cross-section flow by using a flow velocity area method.

As a further improvement of the invention, the number m of speed measuring vertical lines is selected according to the requirements of river flow test regulations, and each vertical line is tested for delta t.

As a further improvement of the invention, the time period between the start time and the end time of the speed measurement is not less than the required test duration delta t.

As a further improvement of the invention, the method also comprises the following steps:

repeating the steps to complete the measurement of the flow velocity of the m vertical lines on the section;

and extracting the flow velocity of each vertical line from the ADCP flow measurement data file, averaging the flow velocity of the test period to be used as the average flow velocity of the vertical lines, and calculating the section flow by using a flow velocity area method.

Compared with the prior art, the invention has the beneficial effects that:

the ADCP flow test method adopting the stop-and-go method can complete the flow test by adopting 1-time flow measurement, and has small workload and reliable precision; the technical problems of large workload and low precision of the sailing ADCP flow measurement under the condition of the ultra-low flow velocity can be solved, and a solution is provided for the river flow test under the ultra-low flow velocity.

Drawings

Fig. 1 is a flowchart of an embodiment of the present invention, which discloses a method for measuring river discharge of an underway ADCP under an ultra-low flow rate condition.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The invention is described in further detail below with reference to the attached drawing figures:

the invention aims to provide a sailing type ADCP river flow testing method suitable for the condition of ultralow flow velocity on the premise of utilizing the existing testing facilities and equipment, which is used for solving the technical problems of large workload and low precision of sailing type ADCP flow measurement under the condition of ultralow flow velocity and provides a solution for river flow testing under the condition of ultralow flow velocity.

The principle of the walking-stopping ADCP flow testing method is as follows:

the 'stop-and-go method' is a flow testing method suitable for ultralow flow rate by combining the advantages of the traditional flow measuring method and the ADCP flow measuring technology; a plurality of vertical lines are arranged in a traditional flow measuring method, a plurality of measuring points are arranged on each vertical line, flow velocity in a certain period of time is collected on the measuring points by a mechanical type current meter, and finally flow is obtained by a flow velocity area method. The flow test principle of the 'walking and stopping method' is that an ADCP is used for replacing a mechanical type flow velocity meter, the average flow velocity of a vertical line is directly measured, and the flow of the cross section is finally calculated; because of the limitations of the ADCP speed measurement working principle, when the flow direction is not set, the positive and negative flow directions cannot be distinguished by the speed measurement vertical line profile, and the flow direction needs to be set artificially. The step in the step-stop method is to run the ADCP from one bank to the other bank for explicitly setting the positive and negative flow directions for ADCP speed measurement; stopping is to directly measure the average flow velocity of the vertical line on the corresponding speed measuring vertical line; and finally, calculating the cross-section flow by using a traditional flow calculation method.

To achieve the above purpose, as shown in fig. 1, based on the above principle, the present invention is applicable to a method for measuring river discharge of an underway ADCP under ultra-low flow rate conditions, including:

step 1, selecting a test scheme: laying a plurality of vertical lines, laying a plurality of measuring points on each vertical line, and arranging ADCP on the vertical lines; wherein the content of the first and second substances,

selecting a test scheme according to the requirements of river flow test specification (GB50179-2015) and the characteristics of the station, and selecting the number m of speed measuring vertical lines and the test duration delta t of each vertical line;

step 2, "walk" and decide the flow direction: the ADCP is operated from one bank of the section to the other bank, and the positive and negative flow directions are set for ADCP speed measurement; recording the shore classification, and starting flow measurement when the ship runs to a corresponding vertical line at normal ship speed;

step 3, stopping to measure the flow rate: the ship is stopped at the speed measurement vertical line, the average flow velocity of the vertical line is directly measured through the ADCP, and the start time and the end time of the speed measurement are recorded; wherein the content of the first and second substances,

the time period between the start time and the end time of the speed measurement is not less than the required testing duration delta t.

Step 4, multi-vertical line test: repeating the steps 2 and 3 to complete the measurement of the flow velocity of the m vertical lines on the section;

step 5, calculating the section flow: calculating the section flow by using a traditional method (flow velocity area method); wherein the content of the first and second substances,

extracting the flow velocity of each vertical line from the ADCP flow measurement data file, taking the average flow velocity of the test period as the average flow velocity of the vertical lines, and completing the cross-section flow calculation by utilizing a traditional method flow calculation program;

step 6, result inspection: and (5) finishing the inspection of the test result according to the related quality control program.

The invention has the advantages that:

the ADCP flow test method of the walking-stopping method controls the precision according to the requirement of river flow test specification (GB50179-2015), and the flow test can be completed by adopting the flow measurement for 1 time; the workload is small, and the precision is reliable.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.