JPS61202134A - Flow direction measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the flow direction in an extremely short time, by a method wherein an air tunnel of a water tank is turned dark in the chamber and partial or whole part of a model or a flow direction indicator is coated with a fluorescent paint to be photographed with a TV camera, the output of which is converted into a binary-coded signal according to brightness to analyze the flow direction. CONSTITUTION:A building model 2 and a topographic model 3 are arranged in the wall 1 of an air tunnel turned dark in the chamber. Tufts 6 coated with a fluorescent paint are arranged on the models 2 and 3 and photographed with a TV camera 7. The output of the camera 7 is sent out to an image analyzer 8 to be converted into a binary signal according to the brightness, the positions of the tufts 6 are analyzed automatically and the air direction angle is shown on an image display 9. Thus, the measurement of the flow direction can be done in an extremely short time.

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION The flow of fluid around a building or around a complex topography varies in various complex ways depending on the thickness and type of the building's structure and the topography.

Wind cylinder experiments or water tanks are generally used to simulate fluid flows in the natural world in a laboratory, but scale models of buildings and terrain are installed inside the wind cylinder or water tank. It is necessary to measure the flow direction on this model.

When measuring the flow direction on such a small model, a sheet pile type flow direction measuring device such as that used for outdoor weather measurements is too large to be used. Conventional hot wire anemometers, 2
This method uses a cylindrical hole pitot tube to measure flow velocity, and is not suitable for measuring the direction of flow.

The two-hole cylindrical pitot tube utilizes the property that, as shown in Figure 3, if two non-parallel pitot tubes are integrated, the reading of the pitot tube will be equal to the flow on the bisector of the angle formed by the pitot tube. This method is used to determine the flow direction of fluid, and is often used in aquariums.

(Problems to be Solved by the Invention) A hot wire anemometer can automatically measure the speed, but it becomes difficult to measure when the direction of the flow of air or water varies greatly.

In addition, the two-hole cylindrical pitot tube requires changing its direction and the impulse tube must be guided outside the flow path, so it is not suitable when a large number of measurement points need to be set. Furthermore, although tufts can be measured even when there are large fluctuations in flow direction, manual reading is required to measure the flow direction, which has the drawback of requiring a large amount of measurement time and cost.

(Means to solve the problem) It took a long time. In contrast, in the present invention, the wind barrel is used as a dark room, the tact is coated with fluorescent paint, the image is photographed by a television camera, the output of this television camera is converted into a binary code by an image analysis device, and the direction of the tuft is numerically determined. Flow direction can be measured in the shortest possible time. In addition, fluorescent paint will be applied to the tuft or its background to facilitate identification by television cameras.

(Example) The present invention will be described in detail with reference to FIG. The flow direction measuring device is the wall l of the wind barrel, the building model 2, the terrain model 3, the blower 4, the rectifying grid 5, and the tuft 6 coated with fluorescent paint (wool, silk thread).
, television camera 7, image analysis device 8, image display device 9,
It is composed of a switch 10, a video recorder 11, and a camera 12. This white image analysis device 8 is a device that converts a black and white image into a black and white binary code.
This is to rectify the turbulent flow of fluid caused by the enlarged flow path after the fluid is discharged. The image analysis device 8 converts the white tufts in the dark background into binary codes, automatically analyzes the orientation of each tuft, and then inputs the wind direction angle to the image display device 9.

(Function) Air is given a wind speed by the blower 4, rectified by the rectifying grid 5, flows through the building model and the terrain model, and then is discharged or circulated. The tufts 6 installed around these models are coated with fluorescent paint, so the tufts glow white in the darkness of the wind barrel, making them easy to photograph with a television camera. In this case, since no illumination light from the outside is required, shadows caused by the building model and the terrain model 2.3 are not caused. The model itself 2.3 is not captured by the television camera 7, and only the signal indicating the tuft 6 is input to the image analysis device.

A switch 10 is configured so that the signal from the television camera 7 is recorded on the video recorder 11 and then input to the image analysis device 8.
It can also be switched by Furthermore, after the tuft 6 is recorded as a still image using the photographic material 12, it can be photographed again using the video camera 7 and inputted to the image analysis device 8.

In the following embodiments, the fluorescent paint was applied to the tufts 6 attached to the building model and the terrain model. If it is not applied to the other side, it is relatively the same as the previous example,
You can get the same result. Of course, it can be applied not only to the entire model but also to only a portion around the tuft.

(Effects of the Invention) As is clear from the above description, according to the present invention,
The orientation of tufts on building and terrain models can be automatically analyzed, and the flow direction angle of each tact can be automatically analyzed in a short time.This allows the flow of air or liquid to be determined on the model and this data can be analyzed automatically. Based on this, the fluid flow in the actual object can be estimated.

[Brief explanation of drawings]

FIG. 1 shows an overall view of the invention, FIG. 2 shows an external view of a hot wire anemometer, and FIG. 3 shows a sectional view of a two-hole cylindrical pitot tube. Explanation of symbols 1...Wind barrel, 2...Building model, 3. Building/terrain model,
4...φ blower, 5... Rectifier grid, 6.0. tact,
7.0. Television camera, 8---Image analysis device, 9...
- Image display device, 10-- Switch, 1111 Video recorder, No. 12 Photographer, 13.14 Heat wire.

Claims (1)

[Claims] In a device that measures the direction of fluid flow around a model placed in a wind barrel or water tank (hereinafter referred to as flow direction),
The wind barrel or water tank in a darkened room, the flow direction indicator placed on the model, the TV camera that photographs the indicator, and the output signal of the TV camera are converted into a binary signal depending on the brightness, and the output signal is converted from this signal. A flow direction measuring device comprising: an image analysis device for analyzing the direction of the flow direction indicator; and a part or all of the model or the flow direction indicator is coated with a tendency paint.