JP4009696B2 - Fluid flow rate calculation method - Google Patents

Description

  The present invention relates to a fluid flow velocity calculation method, and more particularly to a fluid flow velocity calculation method for measuring a flow velocity by installing a sensor structure in the fluid.

  The need for detection and monitoring of water flow in rivers has increased due to the frequent occurrence of disasters in recent years. Conventional river flow detection and monitoring techniques usually use the “floating method”, which measures the time it takes for a float to float over the river and flow over a certain distance. However, in the “Floating Method”, 1) difficulty in securing specialized observers, 2) delays and difficulties in emergency response due to delays in arrival of observers due to floods, etc., 3) difficulties in continuous observation, and 4 ) There are many problems such as possible errors.

  Especially in recent disasters, torrential rains have occurred more frequently than ever before, and the time until rivers are flooded has become shorter, and real-time information has become increasingly necessary. Currently, the Ministry of Land, Infrastructure and Transport and prefectures use telemeters to publish real-time observations of rainfall and water levels. However, flooding downstream of rivers has a large influence on upstream flow, and real-time flow and flow velocity measurements are not possible. It has become very important.

  For this reason, as shown in Patent Document 1 to Patent Document 3, various non-contact type flow meters are being developed.

Patent Publication 2004-117119 Patent Publication 2003-344049 Patent Publication 2000-111375

  In Patent Document 1, a video camera and a water level meter are used to analyze the surface water flow image signal and the water level data to measure the surface flow velocity and flow rate. When it is unclear, it cannot be measured accurately.

  Patent Document 2 is a method in which a stepped portion of a river is photographed from the downstream side with a TV camera and digitally processed to obtain a water level and a flow rate on the higher step side. There is a problem.

  In Patent Document 3, a flow rate is continuously measured by simultaneously measuring a flow velocity, a water level, and a river bed level by an acoustic Doppler velocimeter, a water level meter, and an acoustic sounding instrument that measures a river bed shape. The flow velocity measurement by the Doppler effect has a problem that the sound wave is attenuated due to suspended sediment, bubbles, etc. during heavy rainfall and becomes impossible to measure.

  Furthermore, each of the above methods is expensive, and it is said that it costs 10 million yen per unit, and there is a problem in cost when applied to many rivers nationwide.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fluid flow velocity calculation method that is advantageous in cost and has high measurement reliability.

In order to achieve the above object, the invention according to claim 1 is a method for calculating the flow velocity of a fluid flowing parallel to the equator plane of a spherical body, which is on the equator of the spherical body and parallel to the fluid flow direction. Measure the pressure at two locations asymmetrically with respect to the central axis of the spherical body, determine the Reynolds number of the fluid from the measured pressure, and determine the kinematic viscosity coefficient and the spherical body of the fluid from the determined Reynolds number. The flow velocity of the fluid is calculated based on the diameter of the fluid.
With this configuration, the Reynolds number of the fluid is determined by two predetermined pressures on the equator of the spherical body.
According to a second aspect of the present invention, in the configuration of the first aspect of the invention, the spherical body is included in the sensor structure, and the sensor structure is mounted on the equator and can measure the pressure of the fluid at that position. At least two pressure sensors and a fixing means for fixing the attitude of the spherical body with respect to the fluid flow to a desired position are provided.

  With this configuration, pressures at different positions that are asymmetric with respect to the flow on the equator of the spherical body are measured.

  According to a third aspect of the present invention, in the configuration of the first aspect of the invention, the spherical body is included in the sensor structure, the sensor structure is mounted on the equator, and the pressure of the fluid at the position is measured. And at least three pressure sensors to be obtained.

  If comprised in this way, the pressure in the position of three different points on the equator of a spherical body will be measured.

  According to a fourth aspect of the present invention, in the configuration of the second or third aspect of the present invention, a three-dimensional acceleration sensor incorporated in a spherical body is further provided.

  If comprised in this way, the absolute position of a spherical body will be discriminate | determined.

  According to a fifth aspect of the present invention, in the configuration of the first aspect of the invention, the spherical body is included in the sensor structure, and the sensor structure is mounted on the equator and can measure the pressure of the fluid at that position. It comprises at least one pressure sensor and rotating means for rotating the spherical body about the direction passing through the spherical north pole and south pole as a rotation axis.

  If comprised in this way, the pressure in the desired different position on the equator of a spherical body will be measured with one pressure sensor.

The invention according to claim 6 is a method for calculating a flow velocity of a fluid flowing in parallel to a cross section orthogonal to the longitudinal direction of the cylindrical body, on a peripheral wall in one of the cross sections of the cylindrical body and parallel to the fluid flow direction. Measure the pressure at two locations asymmetric with respect to the central axis of the cylindrical body, determine the Reynolds number of the fluid from the measured pressure, and determine the kinematic viscosity coefficient and the spherical body of the fluid from the determined Reynolds number. The flow velocity of the fluid is calculated based on the diameter of the fluid.
With this configuration, the Reynolds number of the fluid is determined by two predetermined pressures on the peripheral wall of the cylindrical body.
In the invention according to claim 7, the cylindrical body is included in a sensor structure,
The sensor structure includes at least two pressure sensors that are attached to a position on the peripheral wall and asymmetric with respect to the flow and that can measure the pressure of the fluid at the position.

  If comprised in this way, the pressure in the asymmetrical and different position with respect to the flow on the specific surrounding wall of a cylinder will be measured.

As described above, according to the first aspect of the present invention, the Reynolds number of the fluid is determined by two predetermined pressures on the equator of the spherical body, so that the reliability of the flow velocity measurement is improved.
In addition to the effect of the first aspect, the invention according to the second aspect can efficiently measure the pressure on the equator of the spherical body.

  In the invention described in claim 3, in addition to the effect of the invention described in claim 1, since the pressure at three different positions on the equator of the spherical body is measured, the pressure required regardless of the posture of the spherical body. Is definitely available.

  In the invention according to claim 4, in addition to the effect of the invention according to claim 2 or 3, since the absolute position of the spherical body is discriminated, the flow of the fluid with respect to the reference direction is taken into consideration by adding the direction of the flow with respect to the spherical body. The direction is determined.

  In the invention according to claim 5, in addition to the effect of the invention according to claim 1, the pressure at a desired different position on the equator of the spherical body is measured by one pressure sensor.

  According to the sixth aspect of the present invention, since the Reynolds number of the fluid is determined by two predetermined pressures on the peripheral wall of the cylindrical body, the reliability of the flow velocity measurement is improved.

  FIG. 1 is a perspective view showing an external shape of a sensor structure according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG.

  Referring to these drawings, a sensor structure 101 is configured around a spherical body 1 made of, for example, stainless steel, and pressure sensors 3a to 3d are attached to the surface on the equator at intervals of 90 degrees from the center. It has been. Further, on the upper side, that is, the north pole side, a hollow columnar support 2 for supporting the spherical body 1 is attached. Further, a pressure sensor 3e similar to the pressure sensors 3a to 3d is attached to the lower side of the spherical body 1, that is, the south pole side.

  Each of the pressure sensors 3a to 3e is configured with a pressure-sensitive rubber sensor as a detection means. The pressure-sensitive rubber sensor is obtained by uniformly dispersing and compounding a conductive substance and a reinforcing material in a nano size in a soft rubber. When the rubber is pressurized and deformed by an external force from the fluid, the pressure is measured by utilizing the fact that the connection state of the internal conductive material changes to show a change in electrical resistance.

  A three-dimensional acceleration sensor 4 is attached to the center of the spherical body 1. Based on the output of the sensor 4, the absolute position and the absolute direction based on the initial installation position and installation direction of the sensor structure 101 are detected. Therefore, the absolute position of the sensor structure 101 can be grasped even in a use state where the sensor structure 101 is not fixed at a specific place. As a result, it is possible to correctly detect not only the flow velocity direction of the fluid flowing around the sensor structure 101 but also the absolute direction of the flow direction.

  Note that the support 2 not only supports the spherical body 1 but also accommodates therein conductors and the like for transmitting outputs from the pressure sensors 3a to 3e and the three-dimensional acceleration sensor 4 to the outside.

  FIG. 3 is an enlarged view of the “X” portion shown in FIG.

  Referring to the drawing, an opening reaching the center from the surface of spherical body 1 is formed, and sensor front cover 5 is attached to the surface side via O-ring 9 in a waterproof state. A rod guide 6 is attached to the inner surface side of the sensor front cover 5, and a waterproof rubber 11 is installed between the sensor front cover 5 and the rod guide 6. A sensor rod 10 is attached to the center of the waterproof rubber 11 so as to be slidable with respect to the rod guide 6.

  An end portion on the inner side of the sensor rod 10 has a flange shape, and a pressure-sensitive rubber sensor 14 for negative pressure is mounted between the outer side of the sensor rod 10 and the inner surface side of the rod guide 6. A sensor housing 7 is attached to the inner side of the rod guide 6. The sensor housing 7 is screwed into the sensor front cover 5 through the rod guide 6 by a plurality of fastening screws 8, and these are integrated.

  A sensor adjustment rod 12 is attached so as to penetrate the central portion of the sensor housing 7. The outer side of the sensor adjustment rod 12 is formed in a flange shape, and a pressure-sensitive rubber sensor 13 for positive pressure is mounted between the outer surface of the sensor adjustment rod 12 and the inner surface side of the sensor rod 10.

  In use, when a negative pressure is generated on the outer surface of the spherical body 1, the sensor rod 10 moves to the right side in the drawing, and as a result, the pressure sensitive rubber sensor 14 is compressed. The negative pressure can be measured by measuring the degree of compression. On the other hand, when a positive pressure is generated on the outer surface of the spherical body 1, the sensor rod 10 moves to the left in the drawing, and as a result, the pressure-sensitive rubber sensor 13 is compressed. The positive pressure can be measured by measuring the degree of compression.

  By adjusting the sensor adjustment rod 12, the degree of compression of the pressure-sensitive rubber sensor 13 and the pressure-sensitive rubber sensor 14 before measurement can be adjusted to a desired value.

  FIG. 4 is a view of the sensor structure shown in FIG. 1 installed in a fluid and viewed from above.

  Referring to the figure, pressure sensors 3 a to 3 d are arranged on the equator of spherical body 1, and pressure sensor 3 a is installed in a so-called facing state where the front side of spherical body 1 is located. In this embodiment, the fluid is assumed to flow parallel to the equator plane.

FIG. 5 shows an experimental pressure distribution actually appearing on the equator of the spherical body 1 placed in a stationary state in a fluid set to a predetermined Reynolds number (1.62 × 10 ⁵ ) in the state of FIG. (Experimental example A).

  Referring to the figure, this pressure distribution excludes the influence of static pressure, and describes only the dynamic pressure. Here, U∞ represents the flow velocity, ρ represents the density of the fluid, P represents the pressure that actually appears on the surface of the spherical body, and P∞ represents the static pressure applied to the surface of the spherical body. Therefore, (P−P∞) represents the dynamic pressure that actually appears on the surface of the spherical body.

  In the figure, the pressure distribution of the dynamic pressure is represented by a coefficient Cp where the pressure coefficient at the front branch point of the spherical body 1 is 1.

  At a certain Reynolds number around the critical Reynolds number, the pressure distribution along the surface of the sphere is positive (+) pressure in front of the sphere flow in the state excluding the static pressure, The pressure is negative (−) from an angle of 40 degrees from the front, and thereafter, the pressure is negative and the pressure distribution is as shown in the figure. If the pressure distribution is determined from the pressures at a plurality of asymmetric points on the surface of the sphere from such experimental data, the flow velocity, pressure and flow direction of the fluid in which the sensor structure is installed can be calculated.

FIG. 6 shows the experimental pressure distribution that actually appears on the equator of a spherical body placed stationary in a fluid set to another Reynolds number (3.18 × 10 ⁵ ) in the state of FIG. It is a schematic diagram (Experiment B). Also in the figure, the pressure distribution of the dynamic pressure is represented by a coefficient Cp where the pressure coefficient at the front branch point of the spherical body 1 is 1.

FIG. 7 shows the experimental pressure distribution actually appearing on the equator of a spherical body placed stationary in a fluid set to another Reynolds number (1.14 × 10 ⁶ ) in the state of FIG. (Experimental example C). Also in the figure, the pressure distribution of the dynamic pressure is represented by a coefficient Cp where the pressure coefficient at the front branch point of the spherical body 1 is 1.

  Next, a method for calculating the flow velocity using the sensor structure according to the first embodiment of the present invention will be described.

  First, the case where the sensor structure 101 is installed in a state of facing the flow will be described. The pressure ratio Pc at the points A and B corresponding to the mounting positions of the pressure sensor 3a and the pressure sensor 3b shown in FIG. It turns out that there is a difference depending on the Reynolds number. On the other hand, in the sensor structure 101 installed in the fluid, the outputs of the pressure sensor 3a and the pressure sensor 3b correspond to the pressures at the points A and B from the facing state. Therefore, these pressures are acquired and the pressure ratio Pc is calculated.

  Next, find out which experimental example the pressure ratio Pc corresponds to, ie, the corresponding Reynolds number. When the Reynolds number is determined, the flow velocity can be calculated from the kinematic viscosity coefficient of the fluid and the diameter of the spherical body 1.

  At this time, if there is no matching Reynolds number, the numerical value is sequentially increased or decreased based on the nearby Reynolds number, and the pressure ratio Pc at the changed Reynolds number is calculated and compared with the actual measurement example. By repeating this, the Reynolds number matching the actual measurement example is found. Based on the found Reynolds number, the flow velocity can be calculated from the kinematic viscosity coefficient of the fluid and the diameter of the spherical body 1.

  Therefore, if it is known that the sensor sphere is installed in a state of facing the flow, the pressure sensor can be attached at a position where the pressure ratio shows a different value depending on the Reynolds number. There should be at least two locations.

  Next, a case where the sensor structure 101 is not installed in a state of facing the flow will be described.

  FIG. 8 is a diagram showing measurement positions on the equator plane of the pressure sensor in such a state.

  Referring to the drawing, in this example, a state in which the sensor structure 101 is rotated counterclockwise by an angle α is shown. That is, the pressure sensor 3a outputs a pressure P0α instead of the pressure P0 at the front branch point, the pressure sensor 3d outputs a pressure P1α instead of the pressure P1, and the pressure sensor 3b outputs a pressure P2α instead of the pressure P2. To do.

  FIG. 9 shows the pressure difference (P1−P2) calculated from the pressure P1 and the pressure P2 shown in FIG. 8 on the vertical axis, and the displacement angle of the sensor structure relative to the flow on the horizontal axis. That is, the sensor structure 101 is rotated counterclockwise from the directly facing position, and the difference between the pressure P1 and the pressure P2 obtained in this state is plotted for each displacement angle. This plot is performed for the above experimental example, that is, for each different Reynolds number. It can be seen from the figure that this pressure difference becomes a different curve depending on each Reynolds number.

  Next, the difference between the actually measured pressure P1α output from the pressure sensor 3d and the pressure P2α output from the pressure sensor 3b is calculated. Based on this difference, three displacement angles are calculated from the intersection with the curve for each Reynolds number in this example. At this stage, the correct Reynolds number cannot be determined and there are three displacement angle candidates.

  FIG. 10 shows the pressure difference (P0−P1) calculated from the pressure P0 and the pressure P1 shown in FIG. 8 on the vertical axis, and the displacement angle of the sensor structure relative to the flow on the horizontal axis. That is, the sensor structure 101 is rotated counterclockwise from the directly facing position, and the difference between the pressure P0 and the pressure P1 obtained in this state is plotted for each displacement angle. This plot is performed for each of the above experimental examples, that is, for each Reynolds number. It can be seen from the figure that this pressure difference also has a different curve depending on each Reynolds number.

  Therefore, the difference between the actually measured pressure P0α output from the pressure sensor 3a and the pressure P1α output from the pressure sensor 3d is calculated. Then, an experimental example passing through the intersection of this difference and the three displacement angles calculated above, that is, a Reynolds number that matches the actual measurement example is determined. Based on the determined Reynolds number, the flow velocity and the correct displacement angle α can be calculated from the kinematic viscosity coefficient of the fluid and the diameter of the spherical body 1.

  In the case where the output value is an intermediate value of the experimental result, the value may be increased / decreased repeatedly based on the close Reynolds number. Finally, the Reynolds number that matches the actual measurement example is found, and the flow velocity and the like are calculated.

  FIG. 11 is a perspective view showing the appearance of a sensor structure according to the second embodiment of the present invention.

  Referring to the figure, a sensor structure 101 is orthogonal to a longitudinal axis direction of a cylindrical body 120, and a horizontally extending cylindrical body 120 attached between a pair of support bodies 121a and 121b extending in a vertical direction. It comprises a plurality of pressure sensors 3 attached to the surfaces of a plurality of peripheral walls appearing on the cross section. The structure of the pressure sensor 3 is the same as that according to the first embodiment.

  Even in this embodiment, the pressure distribution generated on the surface of the cylindrical body 120 is determined from the properties of the fluid and the flow velocity similarly to the spherical body. Therefore, the flow velocity can be measured from the output of each pressure sensor 3. It becomes possible. In this embodiment, the pressure sensors 3 are arranged in a plurality of rows in the longitudinal axis direction of the cylindrical body 120, but the pressure sensors 3 may be arranged in a single row.

  Further, in this embodiment, two pressure sensors 3 are attached at positions asymmetric to the flow for each row, but if there are three or more, the position is any position on the same peripheral wall. There may be.

  FIG. 12 is a perspective view showing the appearance of a sensor structure according to the third embodiment of the present invention.

  Referring to the drawing, the sensor structure 101 includes a cylindrical body 123 extending in the vertical direction and a plurality of pressure sensors 3 attached to the surface of each peripheral wall. The structure of the pressure sensor 3 is the same as that according to the first embodiment.

  Even in this embodiment, the pressure distribution generated on the surface of the cylindrical body 123 is determined from the properties of the fluid and the flow velocity similarly to the spherical body. Therefore, the flow velocity can be measured from the output of each pressure sensor 3. It becomes possible. In this embodiment, the pressure sensors 3 are arranged in a plurality of rows in the longitudinal direction of the cylindrical body 123, but the pressure sensors 3 may be a single row.

  Further, in this embodiment, two pressure sensors 3 are attached at positions asymmetric to the flow for each row, but if there are three or more, the position is any position on the same peripheral wall. There may be.

  For example, when the sensor structure 101 is installed vertically in a river, it is possible to detect whether each of the pressure sensors 3 is in contact with water. Therefore, if the absolute position of each pressure sensor 3 in the vertical direction is determined in advance, the water level can be detected together with the flow velocity.

  FIG. 13 is a perspective view showing the appearance of a sensor structure according to the fourth embodiment of the present invention.

  Referring to the figure, a sensor structure 101 includes a pair of vertical plates 25a and 25b extending in parallel with each other in the vertical direction, a horizontal plate 26 extending in the horizontal direction attached so as to be stretched over the lower ends thereof, and a vertical plate. 25a and 25b and a plurality of pressure sensors 3 attached to the inner surface side of the horizontal plate 26. The structure of the pressure sensor 3 is the same as that according to the first embodiment.

  Even in this embodiment, the pressure distribution generated on the surface thereof is determined from the properties of the fluid and the flow velocity as in the case of the spherical body or the cylindrical body. Therefore, the flow velocity can be measured from the output of each pressure sensor 3. It becomes possible. It is also possible to detect whether each of the pressure sensors 3 attached to the vertical plates 25a and 25b is in contact with water. Therefore, if the absolute position in the vertical direction of each of these pressure sensors 3 is determined in advance, it is possible to detect the water level as well as the flow velocity.

  FIG. 14 is a schematic view showing a mounting state of the sensor structure according to the first embodiment.

  Referring to the drawing, a support body 2 protruding from a spherical body 1 extends vertically upward, and a fixed body 16 made of a steel pipe or the like is connected to the support body 2 via a flange. The fixed body 16 is attached to, for example, a bridge body as will be described later.

  In such an attached state, since the fixing portion 2 is located directly above the sensor structure 101, pressure data of the portion directly above the spherical body 1 cannot be detected. The pressure sensor 3 can obtain pressure data necessary for calculating the flow velocity.

  FIG. 15 is a schematic view showing another mounting state of the sensor structure according to the first embodiment.

  Referring to the drawing, a support body 2 protruding from a spherical body 1 extends horizontally rearward and then bends upward, and a fixed body 16 made of a steel pipe or the like extending vertically is connected to this via a flange. The fixed body 16 is attached to, for example, a bridge body as will be described later.

  In such an attached state, the pressure data of the rear part of the spherical body 1 cannot be detected because the fixing part 2 is in the rear part of the sensor structure 101, but the other parts are symmetrical with respect to the flow. Since it is in a state, accurate pressure detection is possible. In addition, it is preferable that the distance from the spherical body 1 of vertical parts, such as the fixing | fixed part 16, shall be about 5 times the diameter of the spherical body 1 so that a flow disturbance may not be caused.

  FIG. 16 is a diagram showing an example in which the sensor structure shown in FIG. 14 is applied to river flow velocity detection, and FIG. 17 is a diagram seen from the XVII-XVII line in FIG.

  With reference to these drawings, the sensor structure 101 is attached to a lifting device 15 fixed to a bridge 28 via a fixed body 16. As the installation position of the sensor structure 101, a portion of the river 46 where the flow is not disturbed is selected, and the pressure of the water flow is detected. In an abnormal state such as a flood exceeding the design specification, the lifting / lowering device 15 is actuated to raise the sensor structure 101 above the water surface to protect it.

  Although the figure shows an example in which the sensor structure is installed on the downstream side of the bridge, it may be installed on the upstream side. Moreover, you may comprise so that the sensor structure 101 may be flipped up instead of raising / lowering.

  18 is a view showing another example in which the sensor structure shown in FIG. 14 is applied to river flow velocity detection, and FIG. 19 is a view as seen from the XIX-XIX line in FIG.

  Referring to these drawings, the sensor structure 101 is attached without being completely fixed. The wire ropes 21a and 21b are stretched between the rope fixing devices 22a and 22b installed on the riverbanks 47a and 47b and the rope fixing device 23 installed on the river bed 33 side, and the wire ropes 21a and 21b. From the middle of the sensor structure 101, the sensor structure 101 is installed at a desired depth via rigid bodies 124a and 124b such as steel.

  Since the sensor structure 101 incorporates the three-dimensional acceleration sensor as described above, even if the sensor structure 101 itself moves, its absolute position is detected from the three-dimensional acceleration sensor. Then, by calculating and processing real-time data from the pressure sensor of the sensor structure 101 based on the absolute position, the flow velocity, the water pressure, and the flow direction can be detected.

  In this example, the two rope fixing devices 22a and 22b on the riverbanks 47a and 47b are installed at one location, but this device is installed at one location, and one wire rope is obliquely close to the opposite shore from that position. A sensor structure may be attached to the wire rope 33 via a rigid body.

  FIG. 20 is a view showing still another example in which the sensor structure shown in FIG. 14 is applied to river flow velocity detection, and FIG. 21 is a view seen from the XXI-XXI line of FIG.

  With reference to these drawings, the sensor structure 101 is attached to the lower surface of the floating body 24 floating on the river 46. One of the wire ropes 21 a is connected to the rope fixing device 22 installed on the riverbank 47 a side, and the other is connected to the floating body 24. Similarly, one of the wire ropes 21b is connected to the rope fixing device 22b installed on the opposite riverbank 47b side, and the other is connected to the floating body 24.

  A sensor structure 101 is attached below the floating body 24 and is installed at a desired water depth position such as a position of about 60% of the water depth close to the average flow velocity of the river 46. The sensor structure 101 is slightly moved back and forth and left and right under the influence of the flow, but correct data can be obtained by the action of the three-dimensional acceleration sensor incorporated in the sensor structure 101 as described above.

  FIG. 22 is a diagram showing still another example in which the sensor structure shown in FIG. 14 is applied to flow velocity detection of a river.

  Referring to the figure, sensor structure 101 is attached below floating body 24, and the flow velocity and the like are measured by sensor structure 101 while floating body 24 flows through river 46. This method is performed at a location where the distance between two points through which the floating body 24 is flowed is known. Since the timepiece function is incorporated in the sensor structure 101, the water surface flow velocity of the river 46 can be obtained from the passing time between two points. The average flow velocity of the river 46 is calculated from the flow velocity on the water surface. On the other hand, since the relative flow velocity at the water depth can be measured from the sensor structure 101, the absolute flow velocity at the position of the sensor structure 101 can be calculated from the water surface flow velocity obtained by the movement of the floating body 24 and the relative flow velocity. It becomes.

  A battery device may be mounted on the floating body 24, and the pressure data obtained by the sensor structure 101 may be wirelessly transferred to the river site management center. Alternatively, since it is necessary to connect a recovery rope to the floating body 24, a cabtyre cable is arranged to the floating body 24 using this rope and power is supplied, and the measurement data is wired from the sensor structure 101. A transfer method may be used.

  FIG. 23 is a diagram showing still another example in which the sensor structure shown in FIG. 14 is applied to flow velocity detection of rivers, lakes, oceans, and the like.

  Referring to the figure, the sensor structure 1 is suspended by a cabtyre cable 27 at a position deeper in the ocean 48 than from the case of a river from a ship, and the flow velocity and the flow direction are determined by a combination of a three-dimensional acceleration sensor and a pressure sensor. Can be detected. Such measurements are very useful for construction of bridges connecting the strait, construction of offshore structures, construction of submarine cables, search for submarine resources, and the like.

  If a temperature sensor is incorporated into the sensor structure 101 at the same time, it is possible to correctly detect the flow velocity, direction, and temperature information of the tide in the ocean 48 on the ship 31 in real time. As a result, it can contribute to fishery resource observation and prediction, fish school observation, red tide occurrence prediction and avoidance, and the like.

  FIG. 24 is a side view showing the appearance of a sensor structure according to the fifth embodiment of the present invention.

  Referring to the drawing, the sensor structure 101 is the same as that according to each of the previous embodiments in that the pressure sensor 3 is provided on the outer surface of the spherical body 1, but in this embodiment, The difference is that only one pressure sensor 3 is provided on the horizontal equator plane. The fixed body 16 fixed to the north pole side of the spherical body and connected to the support body 2 extending vertically upward via a flange is connected to a driving device (not shown) so as to be able to rotate around its axis.

  When the driving device is driven, the spherical body 1 rotates and the pressure sensor 3 moves on the horizontal equator plane. Therefore, it is possible to stop the pressure sensor 3 at a desired rotation angle and sequentially measure the pressure at that position. Although the time lag of measurement at each rotational position is about several tens of seconds, this time lag is not a practical problem because the time change of the flow of rivers and the like is usually more gradual. Therefore, according to this embodiment, the pressures at all points around the equator can be measured by only one pressure sensor 3. The flow velocity and the like can be calculated using the above-described method based on the plurality of pressure data thus measured.

  In this embodiment, one pressure sensor 3 is used. However, a plurality of pressure sensors may be attached to the spherical body 3 and rotated. Further, although the rotation axis is the vertical direction, the direction of the rotation axis may be set to a desired direction according to the application.

  FIG. 25 is a diagram showing an example in which the sensor structure shown in FIG. 24 is applied to river flow velocity detection.

  With reference to the figure, an acoustic sounding sensor 30 is attached to an obliquely lower part of the sensor structure 101. This sensor structure 101 is placed in the water at the center of the river 46, and is rotated around the vertical axis using the drive device (not shown). As a result, the acoustic depth sensor 30 irradiates the riverbed 33 with an ultrasonic beam over a wide range, and the reflected beam can be measured to specifically measure the cross-sectional shape of the riverbed 33.

  On the other hand, since the desired pressure data around the equator can be obtained from the sensor structure 101, the flow velocity of the river 46 is calculated. As a result, when combined with the cross-sectional shape of the riverbed 33 measured by the acoustic sounding sensor 30, a more accurate flow rate of the river 46 can be obtained.

  In the above description, only one acoustic depth sensor 30 is used. However, depending on the shape of the riverbed 33, a plurality of acoustic depth sensors 30 may be attached to the spherical body 1 in order to cover a necessary irradiation range.

  FIG. 26 is a diagram showing an example in which the sensor structure shown in FIG. 14 is applied to flow velocity detection in a water tank or the like.

  Referring to the drawing, sensor structure 101 is fixed to bottom surface 36 of tank 35 or aquarium water tank 35 with support 2 and fixed body 16 facing downward. Such a method of use is used when it is difficult to attach from above, or when the attachment length becomes long even if attachment is possible. According to this method, since the sensor structure 101 is attached to the bottom surface 36, there is little possibility of damaging the appearance, and since there is no structure above the sensor structure 101, it is easy to use. As described above, it is possible to detect a change in the water flow on the bottom surface 36 side of the retained water 49 in the water tank 35 based on the output of the sensor structure 101.

  FIG. 27 is a block diagram showing a configuration of a fluid measurement and fluid management system using the sensor structure described above.

  Referring to the figure, various data on pressure, water level and direction obtained by installing the sensor structure in a river or the like are promptly sent to a river management office using a line such as ISDN. Therefore, the analog value data is converted to digital values and calculated by the computer using the calculation algorithm that predicts the water flow from the surface pressure established from the numerical simulation and experimental results of the flow based on the fluid dynamics theory as described above. Is done. The data such as water pressure, flow velocity, flow rate, water level, direction, etc. obtained as a result are sent to the river management center such as a public entity over the Internet in real time, and the flow rate monitoring and management is accurately performed in real time. Done.

  FIG. 28 is a schematic sectional view of a sensor structure according to a sixth embodiment of the present invention, which corresponds to FIG. 2 according to the first embodiment, and FIG. 29 is shown in FIG. It is an enlarged view of "Y" part.

  Referring to these drawings, the structure of the pressure sensor 3 attached to the surface of the spherical body 1 is basically the same as that according to the first embodiment. However, this embodiment is greatly different in that a sensor holder 38 whose surface is aligned with the spherical body 1 is attached to the outer side of the pressure sensor 3c. An opening 39 is formed at the center of the sensor holder 38, and a fluid stagnation portion 40 having a size that exposes the sensor rod 10 is formed therein. The diameter of the fluid stagnation part 40 is set larger than the diameter of the opening 38. As a result, the detected pressure value is stabilized and the detection error is reduced as compared with the configuration according to the first embodiment in which the sensor rod 10 is directly exposed to the outside.

  Further, a fluid ejection hole 41 formed in a radial shape is connected to the fluid stagnation part 40, and the fluid supply hole 44 is connected to the fluid ejection hole 41 via a fluid holding part 43 formed in a ring shape. Depending on the fluid conditions, foreign matter may accumulate in the opening 39 or the fluid stagnation part 40. In such a case, a fluid such as air or water may be periodically ejected from the support 2 to the fluid supply hole 44. The fluid ejected into the fluid supply hole 44 is blown into the fluid stagnation part 40 through the fluid ejection hole 41, and foreign matter in the fluid stagnation part 40 can be removed outward through the opening 39. In this embodiment, since the fluid ejection hole 41 is formed so as to enter obliquely with respect to the fluid stagnation portion 40, the ejection flow generates a vortex, further improving the foreign matter removal effect. I am letting.

  In the first embodiment, the pressure sensors are attached at four locations on the equator. However, if there are fixing means that can be fixed at desired asymmetric positions with respect to the flow velocity direction, The sensor may be installed in two places. If there is no fixing means, three or more locations are sufficient.

  In the first embodiment, the three-dimensional acceleration sensor is incorporated, but this sensor is not necessarily required.

  Further, in each of the above embodiments, a pressure-sensitive rubber sensor is used as a pressure sensor, but a sensor having another configuration may be used.

  Furthermore, in the first embodiment, the method for calculating the flow velocity from the pressure is shown. However, this method is merely an example, and the flow velocity can be calculated from the pressure by another method.

  Further, in each of the above-described embodiments, the shape does not converge in a certain direction with respect to the flow velocity. May be. In this case, since the orientation of the main body is automatically fixed with respect to the flow velocity, the flow velocity can be calculated more easily from the measured pressure.

It is a perspective view which shows the external appearance shape of the sensor structure by 1st Embodiment of this invention. It is sectional drawing of the II-II line of FIG. FIG. 3 is an enlarged view of an “X” portion shown in FIG. 2. It is the figure which installed the sensor structure shown in FIG. 1 in the fluid, and was seen from the upper direction. In the state of FIG. 4, it is the schematic which showed the experimental pressure distribution which actually appears on the equator of the spherical body installed in the stationary state in the fluid set to the predetermined Reynolds number (1.62 × 10 ⁵ ). Yes (Experimental Example A). In the state of FIG. 4, it is the schematic which showed the experimental pressure distribution which actually appears on the equator of the spherical body installed in the stationary state in the fluid set to other Reynolds number (3.18 × 10 ⁵ ). Yes (Experimental Example B). In the state of FIG. 4, it is the schematic which showed the experimental pressure distribution which actually appears on the equator of the spherical body installed in the stationary state in the fluid set to other Reynolds numbers (1.14 × 10 ⁶ ). Yes (Experimental Example C). FIG. 5 is a diagram illustrating a measurement position on the equator plane of the pressure sensor when the sensor structure 101 illustrated in FIG. 4 is not installed in a state of facing the flow. The pressure difference (P1-P2) calculated from the pressure P1 and the pressure P2 shown in FIG. 8 is taken on the vertical axis, and the displacement angle of the sensor structure relative to the flow is taken on the horizontal axis. The pressure difference (P0-P1) calculated from the pressure P0 and the pressure P1 shown in FIG. 8 is taken on the vertical axis, and the displacement angle of the sensor structure relative to the flow is taken on the horizontal axis. It is a perspective view which shows the external appearance shape of the sensor structure by 2nd Embodiment of this invention. It is a perspective view which shows the external appearance shape of the sensor structure by 3rd Embodiment of this invention. It is a perspective view which shows the external appearance shape of the sensor structure by 4th Embodiment of this previous this invention. It is the schematic which showed the attachment condition of the sensor structure by previous 1st Embodiment. It is the schematic which showed the other attachment condition of the sensor structure by previous 1st Embodiment. It is a figure which shows the example which applied the sensor structure shown in FIG. 14 to the flow velocity detection of a river. It is the figure seen from the XVII-XVII line of FIG. It is a figure which shows the other example which applied the sensor structure shown in FIG. 14 to the flow velocity detection of a river. It is the figure seen from the XIX-XIX line of FIG. It is a figure which shows the further another example which applied the sensor structure shown in FIG. 14 to the flow velocity detection of a river. It is the figure seen from the XXI-XXI line of FIG. It is a figure which shows the further another example which applied the sensor structure shown in FIG. 14 to the flow velocity detection of a river. It is a figure which shows the further another example which applied the sensor structure shown in FIG. 14 to flow volume detection, such as a river, a lake, and the ocean. It is a side view which shows the external appearance shape of the sensor structure by 5th Embodiment of this invention. It is a figure which shows the example which applied the sensor structure shown in FIG. 24 to the flow velocity detection of a river. It is a figure which shows the example which applied the sensor structure shown in FIG. 14 to the flow velocity detections, such as a water tank. It is the block diagram which showed the structure of the fluid measurement and fluid management system by the sensor structure by each embodiment. It is a schematic sectional drawing of the sensor structure by 6th Embodiment of this invention, Comprising: It is a figure corresponding to FIG. 2 by previous 1st Embodiment. FIG. 29 is an enlarged view of a “Y” portion shown in FIG. 28.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Spherical body 2 ... Support body 3 ... Pressure sensor 4 ... Three-dimensional acceleration sensor 13,14 ... Pressure-sensitive rubber sensor 38 ... Sensor holder 39 ... Opening 40 ... Fluid squeezing part 41 ... Fluid ejection hole 42 ... Holder main body 101 ... Sensor structure Body 120, 123... Cylindrical body The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (7)

A method for calculating the flow velocity of a fluid flowing parallel to the equatorial plane of a sphere,
Measuring two pressures on the equator of the spherical body at positions asymmetric with respect to the central axis of the spherical body parallel to the fluid flow direction;
Determining the Reynolds number of the fluid from the measured pressure;
A fluid flow velocity calculation method that calculates the fluid flow velocity from the determined Reynolds number based on a kinematic viscosity coefficient of the fluid and a diameter of the spherical body. The spherical body is included in the sensor structure,
The sensor structure is
At least two pressure sensors mounted on the equator and capable of measuring the pressure of the fluid at that location;
The fluid flow velocity calculation method according to claim 1, further comprising a fixing unit that fixes a posture of the spherical body with respect to the fluid flow to a desired position. The spherical body is included in the sensor structure,
The sensor structure is
The fluid flow velocity calculation method according to claim 1, further comprising at least three pressure sensors mounted on the equator and capable of measuring the pressure of the fluid at the position. The fluid flow velocity calculation method according to claim 2, further comprising a three-dimensional acceleration sensor incorporated in the spherical body. The spherical body is included in the sensor structure,
The sensor structure is
At least one pressure sensor mounted on the equator and capable of measuring the pressure of the fluid at that position;
The fluid flow velocity calculation method according to claim 1, further comprising: a rotating unit that rotates the spherical body with a direction passing through the north pole and the south pole of the spherical body as a rotation axis. A flow velocity calculation method for fluid flowing parallel to a cross section perpendicular to the longitudinal direction of a cylindrical body,
Measuring two pressures on a peripheral wall in one of the cross sections of the cylindrical body at positions asymmetric with respect to the central axis of the cylindrical body parallel to the fluid flow direction;
Determining the Reynolds number of the fluid from the measured pressure;
A fluid flow velocity calculation method for calculating a fluid flow velocity from the determined Reynolds number based on a kinematic viscosity coefficient of the fluid and a diameter of the cylindrical body. The cylindrical body is included in a sensor structure,
The sensor structure is
A position on the peripheral wall of the cylindrical body, which is attached to a position asymmetric with respect to the flow, and includes at least two pressure sensors capable of measuring the pressure of the fluid at the position. Of calculating the flow velocity of the fluid.

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