尖劈对大气边界层试验风场的影响

Effect of Spiers in Atmospheric Boundary Layer Simulation

尖劈是风洞生成边界层风场的主要装置,对下游风场的剖面特征有明显的控制作用,但由于作用机制不明确,在风场调试中大多是依据经验布置尖劈,调试效率低。笔者通过风洞试验,得到了3种常用形状(梯形、三角形及曲边三角形)尖劈下游的风速剖面和湍流度剖面特征,并测试了尖劈数量、高度的影响。结果表明:尖劈形状与生成边界层风场的范围高度、指数率直接相关,尖劈的平均宽度越宽,影响高度越高,指数率越大;增加尖劈数量可提高下游风场的指数率,但对风场范围影响很小;抬高尖劈的高度可增加下游边界层风场的高度,配合使用挡板及粗糙元,可以快速调试出目标风剖面。

At present,spiers is the main devices of the wind tunnel simulation,spiers has obvious control of wind profile.However,due to the unclear action mechanism,the spiers are mostly arranged according to experi⁃ence in wind profile adjusted.In this paper,three common spiers shape are used(trapezoidal,triangular and crooked triangle)to obtain the characteristic of the wind profile and turbulence intensity profile.The impact of the changes in the shape,the number and the location of spiers are also studied.The results show that the shape of the wedge is directly related to the height of the boundary layer wind field and the power exponent.The wider the average width of the wedge,the higher the impact height and the greater the power exponent.Increasing the number of sharp wedges can increase the power index of the downstream wind field,but has little effect on the wind field range;Raising the height of the wedge can increase the height of the downstream boundary layer wind field.With the use of baffles and roughness elements,the target wind profile can be quickly debugged.