JPH09126766A - Method and device for measuring water level and wave cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the water level and the wave cycle of a wave by detecting the change in the temperature distribution of the height direction of the shell of a hull side by a plurality of temperature sensors and inputting the result of this detection to an arithmetic means so as to perform an operation. SOLUTION: The containers C1 to C5 of temperature sensors are connected to a microcomputer 2 as an arithmetic means and a temperature detected value is inputted to from each temperature sensor to the microcomputer. A wave height is calculated based on a temperature change. A difference occurs between the temperature of a portion of the shell of a hullside 6 in contact with sea water detected by the temperature sensor of each of the containers C1 to C3 and the temperature of a portion of the shell 6 not in contact with the sea water detected by the temperature sensor of each of the container C4 and C5 . This occurs because of each specific heat. By providing te container C5 in a position higher than a wave head WH, providing the container C1 always in a position lower than a draft line and comparing the temperature of a portion not in contact with the wave with that of a portion in contact with the wave, a clear temperature difference is obtained and thus, measuring accuracy is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water level / wave period measuring method and apparatus for measuring the water level / wave period of waves generated on the side of a ship during navigation.

[0002]

2. Description of the Related Art In designing a ship, it is indispensable for structural safety to find the stress generated in the hull due to waves during navigation. Although such stress can be obtained by numerical calculation, it must be compared with the stress actually generated. Numerical parameters for calculating stress are water level and wave period.

As a device for measuring the water level, there are a device for measuring the distance to the water surface using ultrasonic waves or electromagnetic waves, and a device for measuring the water level from the change in the electric resistance value using the electric capacity of water.

[0004]

However, the apparatus for measuring the water level using ultrasonic waves or electromagnetic waves is very expensive and cannot be easily installed in large numbers. Further, the device using the electric capacity is not suitable for actual ship measurement because it is necessary to attach a sensor to the outside of the outer shell of the ship, and the sensor is peeled off or the sensor causes wave-making resistance.

Therefore, an object of the present invention is to solve the above problems and to provide a water level / wave period measuring method and apparatus capable of stably measuring the water level / wave period with a simple structure over a long period of time.

[0006]

In order to achieve the above object, the present invention provides a water level measuring method for measuring the water level of a wave generated on the side of a ship which is navigating, at a plurality of positions in the height direction of a side shell of a ship. While detecting the outer plate temperature, the water level is measured from the temperature change.

In order to achieve the above object, the present invention is a water level measuring device for measuring the water level of a wave generated on the side of a ship which is navigating, and a plurality of temperature sensors provided in the height direction on a ship side outer plate of a hull, The detection value of the temperature sensor is input, and a calculation means for calculating the water level from the temperature change is provided.

In order to achieve the above object, the present invention is a wave period measuring method for measuring the period of waves generated on the side of a ship during navigation, in which the outer plate temperatures at a plurality of points are detected in the height direction of the side plate of the hull. In addition, the wave period is measured from the temperature change.

In order to achieve the above object, the present invention is a wave period measuring apparatus for measuring the period of a wave generated on the side of a ship which is navigating, and a plurality of temperature sensors provided in a height direction on a side plate of a ship. The detection value of each temperature sensor is input, and a calculation means for calculating the wave period from the temperature change is provided.

Since there is a difference between the specific heat of water and the specific heat of the ship-side outer plate (steel plate), the temperature is different between the part where the ship-side outer plate is in contact with water and the part where it is not in contact with water. By detecting such a change in the temperature distribution in the height direction of the ship-side outer plate with a plurality of temperature sensors and inputting it to the calculating means for calculation,
Wave level and wave period are measured.

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 2 is a side view of a ship equipped with the water level / wave period measuring device of the present invention, FIG. 1 is a partial sectional view taken along the line AA, and FIG. 3 is an enlarged sectional view of a circle B. .

In FIG. 2, _five vessels C _{1 to} C ₅ accommodating temperature sensors are provided in the height direction inside the outer shell plate on the starboard front side of the vessel 1 in the height direction as shown by the broken line. .

As shown in FIG. 1, the container C of each temperature sensor
_{1 to} C ₅ are microcomputers 2 as arithmetic means
It is connected to the. Detected values of temperature from each temperature sensor are input to the microcomputer 2, and the wave height is calculated from the temperature change. A power supply 3 for a heater, which will be described later, is connected to the microcomputer 2.

As shown in FIG. 3, a temperature sensor (for example, a thermocouple) 4 is directly attached to the inside of the outer shell 6 of the ship by an adhesive 5 or the like. A box-shaped container C ₃ is attached to the ship-side outer plate 6 so as to cover the temperature sensor 4 with an adhesive 7 or the like and is hermetically sealed. A heater 8 for heating the internal air is provided inside the container C ₃ , and the on / off of the heater 8 is controlled by the microcomputer 2 (see FIG. 1).

When the water level is measured by the water level measuring device having such a structure, the result as shown in FIG. 4 is obtained. In the figure, the horizontal axis represents temperature and the vertical axis represents water level. Each point P ₁ to P ₅ of the vertical axis corresponds to the position of the container C ₁ -C ₅ for each temperature sensor.

From the figure, the temperatures detected by the temperature sensors of the containers C _{1 to} C _{3 in} the part where the ship side skin 6 is in contact with water (seawater) and the parts where the ship side skin 6 is not in contact with water are shown. Each container C
_It can be seen that there is a difference between the temperatures detected by the temperature sensors ₄ and C ₅ . This is the specific heat of water and the outer shell of the ship (steel)
This is because there is a difference with the specific heat of. That is, it means that the wave crest _WH is located at the portion where the temperature difference occurs (containers C ₃ and C ₄ ). Here, since the water level changes with time as shown in FIG. 5, it goes without saying that the portion of the characteristic curve L shown in FIG. 4 where the temperature difference occurs moves up and down with time. In addition, the container C ₅ is wavefront W _H
By providing the container C ₁ at a higher position and always lower than the water line and comparing the temperature of the part where the waves hit and the temperature of the part where the waves do not hit, the temperature difference becomes clear and the measurement accuracy improves. .

FIG. 4 shows the relationship between the height (water level) of the ship-side outer plate shown in FIG. 1 and temperature, and FIG. 5 shows the relationship between time and water level as seen from the temperature sensor shown in FIG. FIG.

In FIG. 5, the difference between the maximum value and the minimum value of the water level is the wave height, and the time between a certain maximum value and the next maximum value is the wave period (which can be converted into a wavelength).

Further, when the difference between the temperature of water and the temperature of air is small (for example, in winter), an error is likely to occur. Therefore, by raising the temperature inside the containers C _{1 to} C ₅ with the heater 8, the temperature can be increased. The change becomes remarkable and the measurement error is reduced. Further the temperature sensor 4 is sealed in the container C ₁ -C ₅ and the side shell 6, it is possible to measure the water level even when the internal hull is oil or water.

As described above, according to this embodiment, a plurality of temperature sensors provided in the height direction on the outer shell of the hull and the detection values of each temperature sensor are input and the water level is calculated from the temperature change. Since it is provided with the means, the water level and the wave period can be stably measured for a long period with a simple configuration. The measured water level and wave period data are recorded on, for example, a floppy disk. It will be useful for designing the next ship based on the water level and wave period data obtained in this way.

In the present embodiment, the case where five temperature sensors are mounted on the inside of the ship-side outer plate has been described, but the number of temperature sensors may be six or more without being limited to this. It may be provided on the outside of the ship or in the outer shell of the ship. Further, although the thermocouple is used as the temperature sensor, a thermistor, a criteristor or the like may be used.

[0023]

In summary, according to the present invention, the following excellent effects are exhibited.

Since the temperature of the outer skin at a plurality of points in the height direction of the outer skin of the hull of the ship is detected and the water level and the wave period are measured from the temperature changes, the water level and the wave can be stably maintained for a long time with a simple structure. The period can be measured.

[Brief description of the drawings]

1 is a partial cross-sectional view taken along the line AA of the ship shown in FIG.

FIG. 2 is a side view of a ship equipped with the water level / wave period measuring device of the present invention.

3 is an enlarged sectional view of a circle B of the partial sectional view shown in FIG.

FIG. 4 is a diagram showing a relationship between water level and temperature of a ship side outer plate shown in FIG. 1.

5 is a diagram showing a relationship between time and water level viewed from the temperature sensor shown in FIG.

[Explanation of symbols]

 2 Computing means (microcomputer) 4 Temperature sensor 6 Ship side outer plate

Claims (4)

[Claims] 1. A water level measuring method for measuring the water level of a wave generated on the side of a ship while navigating, detecting the skin temperature at a plurality of points in the height direction of the ship side skin of the hull, and measuring the water level from the temperature change. A method for measuring water level, characterized by: 2. A water level measuring device for measuring a water level of a wave generated on a ship's side during navigation, wherein a plurality of temperature sensors provided in a height direction on a side plate of a hull and detection values of the temperature sensors are input. A water level measuring device comprising: a water level calculating unit that calculates a water level based on a temperature change. 3. A wave period measuring method for measuring a period of a wave generated on a side of a ship while navigating, detecting a temperature of an outer plate at a plurality of positions in a height direction of a side plate of a hull, and measuring the wave period from the temperature change. A method for measuring a wave period, which comprises: 4. A wave period measuring device for measuring the period of waves generated on a ship's side during navigation, wherein a plurality of temperature sensors provided in a height direction on a ship side outer plate of a hull and detection values of the respective temperature sensors are input. In addition, the wave period measuring device is provided with a calculating means for calculating the wave period from the temperature change.