JPH0416189Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a turbulence generating device that generates turbulence in fluid flowing in a wind tunnel or a water tank.

[Conventional technology]

Wind tunnels are used to simulate in the laboratory the dispersion of smoke from chimneys and tunnel exhaust stacks, and the turbulence of wind caused by skyscrapers. Also, bridges, chimneys,
Wind tunnel experiments and water tank experiments are indispensable to examine the wind resistance and flow resistance of structures exposed to wind and water flows, such as offshore structures. It is extremely difficult to reproduce this in a wind tunnel or an aquarium.

Conventional methods for generating turbulence include placing grids in the fluid and placing flags, but both methods are difficult to measure experimentally, response analysis is extremely complex and difficult to understand, and it is difficult to reproduce natural turbulence. It lacked practicality due to its insufficiency and other factors.

Therefore, as shown in FIG. 3, a device has been proposed and put into practical use that rotates a rotating plate within a flow path to generate turbulence in the flow.

This device consists of rotary plates 02 arranged horizontally in a wind tunnel outlet 01, arranged in a row perpendicular to the flow path, and the left and right ends of the rotary shafts 04 attached to a frame 06 via bearings (not shown). It is designed so that it can be rotated.

Rotation of the rotary plate 02 is performed by forward and reverse rotation of a motor 03 that meshes with a gear 05 attached to each rotary shaft 04.

[Problems to be solved by the invention] In such a conventional device, fluctuating wind is generated by the swinging of the rotating plate 02, but in this case, the fluctuating wind is directed in the direction of the rotating axis 04 of the rotating plate 02. They will have the same fluctuating wind speed at the same time. However, natural wind does not have such a simple distribution, but usually has a three-dimensional variable wind speed distribution. In other words, if the distance between two points in space is x, and the correlation coefficient of fluctuating wind speed between those two points is Rx, then in the case of natural wind, as shown by solid line A in Figure 4, x = 0 (same point )
Then, Rx=1 (perfect correlation), and as x becomes larger, Rx approaches 0 (no correlation). On the other hand, in the case of the fluctuating wind caused by the rotating plate 02, as shown by the dashed line B, even if x becomes large, only a slight attenuation is observed and Rx becomes approximately 1. According to this,
The fluctuating aerodynamic force that acts on bridges, chimneys, etc.
This is different from natural wind, and it is not possible to accurately reproduce actual phenomena.

[Means for solving problems]

The present invention consists of a rectangular rotating plate that is perpendicular to the flow and swingably supported in the flow path of a wind tunnel or water tank, and a drive mechanism that rotates the rotating plate. In the turbulence generating device for generating turbulence, the rotary plate is formed of a flexible member, and both ends of the rotary plate are rotated by a set of independent drive mechanisms.

[Effect]

In the device of the present invention, the rotating plate is formed of a flexible member, and both ends of the rotating plate are rotated independently. Therefore, the rotary plate twists and rotates, and the rotation angle changes in the length direction, and the uniform fluctuating wind as in the conventional case does not occur.

〔Example〕

Hereinafter, the present invention will be described with reference to an embodiment of the apparatus shown in FIGS. 1 and 2, and this embodiment is also an example of a wind tunnel, as in FIG. 3.

A frame 6 is attached to the air outlet 1 of the wind tunnel, and rotation shafts 4A and 4B fixed to both ends of a rotation plate 2, which will be described later, are held by bearings (not shown). The rotating plate 2 is made of a flexible member such as rubber, vinyl, or a thin metal plate, and both ends thereof are fixed to rotating shafts 4A and 4B. In addition, if the rigidity in the axial direction is too low and the structure sags, insert a beam as appropriate.

3A and 3B are motors, and rotation axes 4A, 4B
Gears attached to and gear group 5 for transmission thereof
This is to rotate A and 5B forward and reverse.

Now, by computer etc., motors 3A, 3
Rotate B independently in forward and reverse directions. Gear group 5
The rotation shafts 4A and 4B are rotated via the shafts A and 5B, an example of which is shown in FIG. The waveform C indicates the rotation angle of the rotation axis 4A, and the waveform D
is that of the rotation axis 4B.

The rotating plate 2 made of a flexible member undergoes continuous torsional deformation due to the independent rotation of rotating shafts 4A and 4B fixed to both ends thereof.

Therefore, different turbulence can be generated in the flow passing between the rotating plates 2 in the longitudinal direction, that is, in the width direction of the wind tunnel outlet 1.

〔effect〕

According to the device of the present invention, it is possible to generate a fluctuating flow having a spatial distribution in a direction perpendicular to the flow in a wind tunnel, a water tank, or the like.

[Brief explanation of drawings]

Fig. 1 is a diagram of a device showing an embodiment of the present invention, Fig. 2 is an illustration of the rotation angle of the rotation axis, Fig. 3 is a diagram of a conventional device, and Fig. 4 is the correlation between distance and wind speed. FIG. 2... Rotating plate, 3A, 3B... Motor.

Claims (1)

[Scope of utility model registration request] It consists of a rectangular rotating plate that is perpendicular to the flow and rotatably supported in the flow path of a wind tunnel or water tank, and a drive mechanism that rotates the rotating plate, generating turbulence in the flow within the flow path. A turbulence generating device characterized in that the rotating plate is formed of a flexible member, and both ends of the rotating plate are rotated by a set of independent drive mechanisms. Device.