Vertical multi-layer current measurement method

Abstract

The vertical multi-layer ocean current measurement method described in the present invention proposes a measurement technology of a double-jet intersection fixed point, in order to complete the efficient, accurate and continuous ocean current measurement of different ocean current layers in the vertical direction by changing the jet angle, avoiding the interference and influence of the underwater environment caused by the emission of light, sound waves and other signals, and having outstanding environmental friendliness. A double-water jet device is used, which is installed on two groups of nozzles on the underwater exploration equipment. The two groups of nozzles have the same vertical installation height, and each group of nozzles can reciprocate horizontally around its fixed axis in the horizontal plane; the two groups of nozzles respectively eject a group of water flow with the same water pressure and direction, and the two groups of water flow form an intersection point on the target to be measured; by changing the jet angle of the two groups of water flow to form an intersection point on the bottom plane of the multi-layer ocean current layer, the following n-th layer of ocean current data is continuously measured.

Description

Technical Field

[0001] The present application relates to the field of marine engineering and underwater exploration, and specifically to a new method for vertical multi-layer current measurement based on the intersection of two underwater currents. Background Art

[0002] Ocean current measurement technology is a key topic in the fields of marine engineering and environmental observation, as well as underwater exploration and research. Existing current measurement methods generally use a variety of equipment such as mechanical current meters, electromagnetic current meters, Doppler current meters, and sound propagation time current meters. The above existing technologies have the disadvantages of high maintenance costs, complex operations, and susceptibility to complex seabed environmental conditions when measuring ocean currents.

[0003] For example, the most commonly used ADCP (Acoustic Doppler Current Profiler) has a complex instrument structure and operation, and is difficult to adapt to underwater measurement requirements under different environmental conditions in terms of measurement time and efficiency. Equipment such as hydroacoustic transducers and electronic signal processors are not only extremely expensive, but also rely on acoustic signals to collect data information during the measurement process, which is more likely to cause ultrasonic noise pollution, causing obvious adverse effects on the physical and mental health of the measurement personnel.

[0004] In view of this, this patent application is proposed. Summary of the invention

[0005] The vertical multi-layer ocean current measurement method described in the present application aims to solve the problems existing in the above-mentioned prior art and proposes a dual-jet intersection fixed point measurement technology, so as to complete the efficient, accurate and continuous ocean current measurement of different ocean current layers in the vertical direction by changing the jet angle, avoiding the interference and influence of the underwater environment caused by the emission of light, sound waves and other signals, and has more outstanding environmental friendliness.

[0006] In order to achieve the above-mentioned design objectives, the vertical multi-layer current measurement method adopts a dual-flow jet device, which is installed on two groups of nozzles on the underwater exploration equipment. The two groups of nozzles have the same vertical installation height, and each group of nozzles can reciprocate in the horizontal direction around its fixed axis in the horizontal plane; the two groups of nozzles respectively eject a group of water flow with the same water pressure and direction, and the two groups of water flow form an intersection point on the target to be measured;

[0007] By changing the jet angles of the two sets of water currents to form a junction point on the bottom plane of the multi-layer current layer, the following n-th layer current data are continuously measured;

[0008] The velocity of the current in the X-axis direction is v xn ,

[0009]

[0010] The velocity of the current in the Y direction is vyn： ,

[0011]

[0012] The direction of the ocean current is, if X n >0, the jet flows along the positive direction of the X-axis of the ocean current; otherwise, it flows along the negative direction of the X-axis;

[0013] like Then the jet flows along the positive Y-axis direction of the ocean current; otherwise, it flows along the negative Y-axis direction;

[0014] Among them, X n , Y n are the coordinates of the jet intersection point on the bottom plane of the nth current layer actually measured by the binocular camera; t n is the time required for two sets of jets to converge;

[0015] h z is the vertical downward displacement distance of the jet intersection point along the Z axis;

[0016] h is the movement distance of each group of jets from the nozzle to the intersection point;

[0017] α n is the angle of rotation of each group of nozzles in the horizontal direction;

[0018] g is the acceleration due to gravity.

[0019] As mentioned above, the advantage of the vertical multi-layer current measurement method of the present application is that it proposes a complete set of efficient underwater current measurement methods, which can cope with the complexity and challenges of the underwater environment based on the dual water current intersection point, improve the efficiency and reliability of underwater current measurement, and meet the needs of different application fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present application is now further described in conjunction with the following drawings;

[0021] Figure 1 is a schematic diagram of a dual water jet device;

[0022] Figure 2 Schematic diagram of jet intersection not affected by ocean current conditions;

[0023] Figure 3 Schematic diagram of jet intersection affected by ocean current conditions;

[0024] Figure 4 Schematic diagram for measuring the ocean current layer;

[0025] Figure 5 This is the measurement principle diagram based on the X-axis direction; DETAILED DESCRIPTION

[0026] In order to further explain the technical means adopted by the present application to achieve the predetermined design objectives, the following preferred implementation scheme is proposed in conjunction with the accompanying drawings.

[0027] In the following description, specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] like Figure 1 As shown, the vertical multi-layer ocean current measurement method of the present application completes the continuous measurement of different ocean current layers in the vertical direction by changing the jet angles of two groups of water currents.

[0029] The dual water jet device used in the method includes two groups of nozzles installed on the underwater exploration equipment. The two groups of nozzles have the same vertical installation height, and each group of nozzles can reciprocate horizontally (swing left and right) around its fixed axis in the horizontal plane. When the two groups of nozzles respectively eject a group of water streams with the same water pressure and direction, the two groups of water streams form an intersection on the target to be measured.

[0030] When measuring underwater currents, the flow pattern of the currents is relatively complex, including horizontal currents and vertical currents. The movement scale of the vertical current is much smaller than that of the horizontal current. Therefore, it can be approximately assumed that the flow of the current has no obvious effect on the vertical displacement of the water flow ejected from the nozzle.

[0031] Under the premise of only considering the influence of horizontal flow and gravity acceleration on the ejected water flow, the vertical multi-layer current measurement method proposed in this application includes the following two situations: First, it is not affected by the current, such as Figure 2 As shown; secondly, affected by ocean currents, such as Figure 3 As shown; regardless of the above situation, the present application uses the jet angles of the two groups of nozzles of the above-mentioned double-flow jet device to control the two groups of water flows to form an intersection on the bottom plane of the layer of ocean current.

[0032] For the first case, mathematical and physical simulation calculations are performed based on the position of the intersection point P. The position of the intersection point P obtained from the calculation results under such ideal conditions without the influence of external factors can serve as a reference point.

[0033] For the second case, the actual position of the intersection point P' can be determined based on the binocular camera, and then the distance change relative to P can be determined. The difference in the distance between the virtual point P and the real point P' in the XY axis direction determined in the two cases is calculated, which is the component velocity v of the current in the XY axis direction. x 、v y The product of the jet intersection time t;

[0034] Based on this, by changing the jet intersection point multiple times so that each intersection point is at a vertical depth of a different layer of ocean current, the ocean current data of multiple different ocean current layers can be continuously measured.

[0035] Embodiment 1, as Figures 2 to 5 As shown, when the underwater exploration equipment equipped with the above-mentioned dual-flow jet device reaches the vicinity of the ocean current layer to be measured, it is assumed that the distribution and layer thickness data of different ocean current layers are measured in advance.

[0036] Using the above-mentioned dual-flow jet device, two groups of nozzles at the same vertical installation height respectively eject a group of water flows forward at the same water pressure and at the same time. The two groups of nozzles 2 rotate inward at the same angle and cooperate with the visual binocular camera for identification. When the intersection point of the two groups of water flows is located on the plane at the bottom of the first layer of ocean current layer, the nozzle stops rotating and the angle sensor and other methods measure the rotation angle of the nozzle as α1, determine the actual intersection point P' at this time, and then obtain the deviation from the position of the intersection point P that is not affected by the ocean current calculated in advance, and finally calculate the speed and direction of the first layer of ocean current layer;

[0037] Subsequently, the two groups of nozzles are controlled to rotate inward or outward at the same time, and a group of water flows are ejected forward at the same time. When the intersection point of the two groups of water flows is located on the plane where the bottom of the second layer of ocean current layer is located, the nozzles stop rotating and the rotation angle of the nozzles is measured as α2 by an angle sensor or other methods. The above steps are repeated to complete the calculation of the speed and direction of the second layer of ocean current layer.

[0038] And so on, the continuous measurement of the speed and direction of n layers of ocean current is completed in sequence.

[0039] Specifically, it is assumed that each current layer flows only in the horizontal plane, and only the influence of the vertically downward gravity on the water flow ejected by the above-mentioned double-flow jet device is considered.

[0040] According to the measurement requirements, it is assumed that the thickness of the current layer to be measured is h z , find the position of the jet intersection at h z , 2h z 、…、nh z The nozzle rotation angle required by the jet device when the pressure is constant. When the pressure is constant, the jet is ejected with a certain initial velocity v0. Let the vertical downward displacement distance of the intersection point in the Z-axis direction be h z When the time required for the intersection is t1. The Z-axis direction can be approximated as free fall motion, and the displacement formula is

[0041]

[0042] The time t1 required to solve

[0043]

[0044] Similarly, when the intersection point is on the plane at the bottom of the nth layer of ocean current, the vertical downward displacement distance in the Z direction is nh z The time t required for the jets to just meet is n

[0045]

[0046] Assume that the distance between the two nozzles of the above-mentioned double water flow injection device is 2h.

[0047] Assuming that the intersection point is on the plane at the bottom of the first layer of ocean current, the inward rotation angle of the jet device is α1, so the initial velocity in the X direction can be approximated to be v X0 =v0·sinα1 uniform linear motion. Since the jets have just intersected, the distance between the two nozzles is 2h, so the jet movement distance at this time is h.

[0048] From the uniform motion displacement formula we get

[0049]

[0050] The inward rotation angle α1 of the nozzle can be solved as

[0051]

[0052] Similarly, the intersection point is at the bottom of the nth layer of ocean current, that is, the vertical downward displacement distance in the Z direction is nh z When the nozzle rotates inwards, the angle should be α n ,but

[0053] When the intersection point is at the bottom of the first layer of ocean current, first calculate the coordinates of the jet intersection point P in the XY axis horizontal plane in the first case without the influence of ocean current:

[0054] The displacement in the Y-axis direction is shown in the figure. In Rt△ACD, according to the trigonometric function relationship

[0055]

[0056] The displacement distance in the Y direction is solved as

[0057]

[0058] Similarly, the displacement distance in the Y direction at the bottom of the nth layer of ocean current at the intersection point can be obtained as

[0059]

[0060] So the coordinates of the intersection point P at the first level are Similarly, the P coordinate of the intersection point at the nth layer can be obtained as

[0061] In the second actual situation, that is, under the influence of ocean current and gravity, when the intersection point is measured by the binocular camera at the bottom of the first layer of ocean current, the coordinates of the intersection point are (X1, Y1). Due to the influence of ocean current, the displacement deviation d in the X direction of the jet intersection point P and P' in the horizontal plane x1 and the displacement in the Y direction d y1 For: x1 =|X1-0|,

[0062]

[0063] Similarly, when the intersection point is at the bottom of the nth layer of ocean current, the jet is displaced d in the X-axis direction of the horizontal plane due to the influence of the ocean current. xn and the displacement d in the Y-axis direction yn They are: d xn =|X n -0|,

[0064] Among them, the above X1, Y1, and X n , Y n These are the coordinate values ​​actually measured by the binocular camera.

[0065] Determination of ocean current speed:

[0066] The first layer of ocean current, the velocity of the ocean current in the X-axis direction is v x , we get d from the displacement formula x1 =v x1 t1,

[0067] D x1 =|X1|, Substituting into the equation, we can get the velocity of the first layer of ocean current in the X-axis direction as v x1 ,

[0068]

[0069] The velocity of the current in the Y direction is v y1 , we get d from the displacement formula y1 =v y1 t1;

[0070] Will Substituting in, we can get the velocity of the first layer of ocean current in the Y-axis direction as v y1

[0071]

[0072] Determination of the direction of ocean current speed:

[0073] If X1>0, the jet flows along the positive direction of the X axis; otherwise, it flows along the negative direction of the X axis;

[0074] like The jet flows along the positive direction of the Y axis; otherwise, it flows along the negative direction of the Y axis.

[0075] The speed and direction of the nth layer of ocean current:

[0076] When the intersection point is at the bottom of the second current layer, due to the influence of the current, the displacement deviation of the jet intersection point P and P' in the X-axis direction of the horizontal plane is d x2 , the displacement deviation in the Y-axis direction is d y2 ,but:

[0077] d x2 =|X2-0|

[0078]

[0079] Because the displacement deviation of the second layer is the superposition of the influence of the first layer current velocity and the second layer current velocity, the displacement formula is:

[0080] In the X-axis direction, d x2 =|X2|=v x1 t1+v x2 (t2-t1); v x1 t1=d x1 =|X1|Substituting into the above formula, we can obtain the velocity of the second layer of ocean current in the X-axis direction as v x2 ,but

[0081] In the Y-axis direction,

[0082] Will Substituting into the above formula, we can obtain the current velocity of the second layer of current in the Y-axis direction as v y2 ,but

[0083] By analogy, the displacement deviation of the third layer is affected by the superposition of the current velocity of the first layer, the current velocity of the second layer and the current velocity of the third layer. According to the displacement formula:

[0084] In the X-axis direction:

[0085] d x3 =|X3|=v x1 t1+v x2 (t2-t1)+v x3 (t3-t2)

[0086] D x2 =|X2|=v x1 t1+v x2 Substituting (t2-t1) into the above formula, we can obtain the current velocity of the third layer of ocean current in the X direction as v x3 ,but

[0087] In the Y-axis direction:

[0088]

[0089] Will Substituting into the above formula, we can obtain the current velocity of the third layer of current in the Y-axis direction as v y3 ,but

[0090] From this conclusion, we can conclude that the velocity of the nth layer of ocean current in the X-axis direction is v xn ,

[0091] but

[0092] The velocity of the nth layer of ocean current in the Y-axis direction is v yn： ,

[0093] but

[0094] The direction of the nth layer of ocean current is, if X n >0, the jet flows along the positive direction of the X-axis of the ocean current; otherwise, it flows along the negative direction of the X-axis;

[0095] like The jet flows along the positive direction of the Y axis of the ocean current; otherwise, it flows along the negative direction of the Y axis.

[0096] As described above, similar technical solutions can be derived from the solutions given in the drawings and descriptions. However, any solution content that does not deviate from the structure of the present invention still belongs to the scope of rights of the technical solution of this application.

Claims

1. A method for measuring vertical multi-layer ocean currents, characterized in that: A double water jet device is used, which includes two groups of nozzles installed on the underwater exploration equipment. The two groups of nozzles have the same vertical installation height, and each group of nozzles can rotate horizontally around its fixed axis in the horizontal plane. The two groups of nozzles emit a group of water streams at the same water pressure and rotate at the same angle respectively, and the two groups of water streams form an intersection on the target to be measured; By changing the jet angles of the two sets of water currents to form a junction point on the bottom plane of the multi-layer current layer, the following n-th layer current data are continuously measured; The velocity of the current in the X-axis direction is v xn , The velocity of the current in the Y direction is v yn , The direction of the ocean current is, if X n >0, the jet flows along the positive direction of the X-axis of the ocean current; otherwise, it flows along the negative direction of the X-axis; like Then the jet flows along the positive Y-axis direction of the ocean current; otherwise, it flows along the negative Y-axis direction; Among them, X n , Y n are the coordinates of the jet intersection point on the bottom plane of the nth current layer actually measured by the binocular camera; t n is the time required for two sets of jets to converge; h z is the vertical downward displacement distance of the jet intersection point along the Z axis; h is the straight-line distance from the nozzle to the intersection point of each group of jets on the x-axis; α n is the angle of rotation of each group of nozzles in the horizontal direction; g is the acceleration due to gravity.

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