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在节段模型风洞试验中,两端设置端板可以有效减小端部效应对风压分布的影响,从而保证气流在模型周围的二维流动,其中端板尺寸是影响端板效果的主要参数。为了明确不同尺寸端板对矩形断面气动特性的影响,以桥梁节段模型中最常见的3种宽高比(B/H分别为1、5和10)的二维矩形断面为研究对象,通过刚性模型测压试验,研究了端板尺寸对各模型的气动力、风压分布和斯托罗哈数St的影响。研究结果表明:模型的端部效应不仅仅对端部附近的风压有影响,对中间位置处风压的影响也不容忽视,设置端板是获得准确试验结果的重要保证;随着断面宽高比(B/H)逐渐增大,端部效应影响的程度和范围逐渐减小;随着端板尺寸的增大,模型背风面风压绝对值逐渐增大并趋向一稳定值;抑制端部效应的最小端板尺寸与结构的风迎角有关,风迎角增大,所需的端板也相应增大;有无端板对斯托罗哈数St也有明显影响。
In the section model wind tunnel test, setting the end plates at both ends can effectively reduce the influence of the end effect on the wind pressure distribution so as to ensure the two-dimensional flow of the gas around the model, wherein the end plate size is the main factor affecting the end plate effect parameter. In order to clarify the influence of end plates with different sizes on the aerodynamic characteristics of rectangular section, two-dimensional rectangular sections with the three most common aspect ratios (B / H = 1, 5 and 10, respectively) The rigid model pressure test, the end plate size of the model of the aerodynamic force, wind pressure distribution and Storr Ha number St impact. The results show that the end effect of the model not only affects the wind pressure near the end but also can not neglect the wind pressure at the middle position. Setting the end plate is an important guarantee for obtaining accurate test results. With the wide and high profile (B / H) gradually increased, and the extent and scope of the influence of the end effect gradually decreased. With the increase of the size of the end plate, the absolute value of wind pressure on the leeward side of the model gradually increased and tended to a steady value. The effect of the minimum end plate size and the structure of the wind angle of attack, the wind angle of attack increases, the required end plate also increased; with or without end plate Storr Ha number St also have a significant impact.