Three-dimensional gradient boundary transition device applied to wind field characteristic wind tunnel experiments of terrain model

Abstract

The invention discloses a three-dimensional gradient boundary transition device applied to wind field characteristic wind tunnel experiments of a terrain model. the boundary transition device is mainly formed by serially connecting and splicing a plurality of sections; each section comprises two side plates and a surface layer; each side plate comprises a vertical edge, a bottom edge and a curve edge; the surface layer is fixedly paved on the curve edges of two corresponding side plates; the vertical edges of the side plates are higher than positions corresponding to the boundaries of the terrain model; the lengths of the bottom edges of the side plates are 5 to 8 % of the width of a wind tunnel; the gradient between the vertical edge of each side plate and the bottom edge of the side plate is 20 to 40 degrees; the line font of the curve edge of each side plate is defined according to the equation that y-r<2> / y+r<2>x<2> / y<3>-r<2>x<4> / y<5>+r<2>x<6> / y<7>-r<2>x<8> / y<9>-m=0, wherein x represents the radial position of each curve edge, y represents the vertical position of the curve edge, the parameters r and m are defined according to the equation set shown in the specification, h0 represents the height of each vertical edge, k0 represents the ratio between the height of the vertical edge and the length of each bottom edge. Through the adoption of the boundary transition device, under the premise that a wind field characteristic meets requirements after airflow transition, the requirement of wind tunnel space is low, and the applicability is high.

Description

technical field [0001] The invention relates to a three-dimensional gradually changing boundary transition device applied to wind tunnel tests of wind field characteristics of terrain models. Background technique [0002] To build a bridge in a mountainous area with complex terrain, it is necessary to obtain the wind characteristic parameters such as the average wind speed and fluctuating wind speed in the bridge site area through the wind tunnel test of the bridge site area model, so as to provide a scientific basis for the wind resistance design and construction of the bridge. In addition, when the macro and micro sites of wind farms are selected in complex mountainous terrain, the wind field parameters at the wind farm site must also be clarified, so as to provide guarantee for the efficient and safe operation of wind turbines. In the wind tunnel test of the wind field characteristics of the terrain model, due to the limitation of the size of the wind tunnel test section,...

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Problems solved by technology

[0003] The existing transition device is mainly composed of multiple straight 30o slope plates spliced ​​at the boundary of the terrain model. When the incoming flow flows to the slope plate, the air velocity will increase along the slope and the pressure will increase due to the pressure of the slope. As it decreases, a forward pressure gradient will be generated. When the airflow reaches the intersection of the slope and the boundary of the terrain model, the velocity will reach the maximum, and the corresponding pressure will reach the minimum at this time, so the terrain model after the intersection will produce The reverse pressure gradient, when the reverse pressure gradient is too large, the flow will separate, which will cause a large change in the wind field characteristics here and the wind field characteristics of the incoming flow, and make the wind field characteristics of the incoming flow in the test lose Reference significance, and ultimately make the test results inaccurate

Although the method of reducing the slope (such as reducing the slope to about 5°) and extending the length of the slope plate can be used to reduce the influence of the reverse pressure gradient on the incoming wind speed of the test, this method will cause the transition section to be too long, which is harmful to the wind tunnel. The space requirements are high, and it is difficult to apply to the needs of conventional wind tunnel tests

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