The wind tunnel rig noise data in Fig.9 compare favourably with the data from other automobile and aeroacoustic wind tunnels published previously [9–11].图9中的风洞装置（rig）噪声数据与以前发表的其他汽车风洞和航空声学风洞的数据顺利地做了比较【9－11】.With the assumption that the variation of sound pressure level in the azimuthal plane is small,4 the OASPL data presented in Ref.[9–11] for the various wind tunnels OASPLiFacility,were corrected for measurement distance riFacility and nozzle area AiFacility to allow comparison with the present open jet wind tunnel by the use of the following:
在假设方位平面上声压水平很小的情况下,对文献【9－11】提供的有关不同风洞（OASPLiFacility,OASPLi设施）的总体声压级（OASPL）数据,针对测量距离（riFacility,ri设施）和喷嘴面积（AiFacility,Ai设施）进行了修正,以便与本开放式风洞用以下公式进行比较：
（公式3）
where riFacility is the distance from the microphone to the centre of the nozzle exit plane of other wind tunnels; and AiFacility is the nozzle cross-sectional areas.AISVR and rISVR are 0.0675 m2 and 0.5 m,
respectively for the ISVR open jet wind tunnel.式中,riFacility为其他风洞从麦克风到喷嘴出口平面中心的距离；AiFacility为喷嘴的横截面积.AISVR和rISVR对于英国南安普顿大学声与振动研究所（ISVR）的开放式风洞来说分别为0.0675m2和0.5m.
Fig.10 presents the distributions of A-weighted OASPL with test section velocity for a number of well-known automobile and aeroacoustic research wind tunnels around the world [9–11].图10介绍了世界上很多著名汽车和航空声学研究风洞,用试验段速度A加权的OASPL的分布.The differences in these measurements can partly be attributed to the fact that the measurement angle h is different for different wind tunnels presented in Fig.10.这些测量值的差别可以部分归咎于图10介绍的不同风洞有不同的测量角h.Fig.10 demonstrates that the A-weighted OASPL at both h = 45 and 90 for the present open jet wind tunnel is comparable with the quietest wind tunnels.图10证明了,对于本开放式风洞来说,在h＝45和90时的A加权OASPL可与最静音的风洞相比美.The figure also shows that the A-weighted OASPL scales with log(V) [7,8] for all the wind tunnels presented.图10还示出了所有介绍的风洞,采用log（V）的A加权OASPL分度【7,8】.
4.2.Analysis of exit flow uniformity and turbulence characteristics
4.2 出口流量均匀性和湍流特性的分析
To investigate the uniformity of the jet flow,the total pressure profiles were measured using a custom-made pitot-tube rake.为了研究射流流动的均匀性,用一个定制的皮托管前刀面（rake）测量了总的压力剖面.The rake consists of eleven 1.2 mm-internal diameter steel tubes located
at 15 mmintervals,which spans the height of the nozzle exit.该前刀面由11根1.2mm直径的钢管,以15mm的间隔放置构成,它跨越喷嘴出口的高度.By assuming the streamwise pressure gradient caused by the jet contraction to be negligible,the static pressure is approximately equal to the atmospheric pressure for the open jet.通过假设射流收缩引起的流向压力梯度为忽略不计,静态压力近似等于开放射流的常压.The jet velocity can thus be deduced from the measured total pressure.The pitottube rake was attached to a computer-controlled two-dimensional traverse mechanism.The accuracy of the traverse in both directions is within ±0.01 mm.因此从实测的总压力可以推导出射流的速度.皮托管前刀面被附于计算机控制的两维横移机构上.两个方向的横移精度都在±0.01mm以内.