汽车模型风洞射流剪切层的非定常结构特性

Unsteady Structure Features of Jet Shear Layer of Vehicle Model Wind Tunnel

针对1:15的3/4开口式整车模型风洞不同收集口角度和喷口速度工况,采用热线风速仪对射流剪切层内的流场进行了多个截面瞬时速度的测量,研究此类风洞的喷口射流剪切层定常与非定常结构.对比分析不同工况下平均速度,速度脉动以及剪切层厚度的变化,得到了各种工况射流剪切层的结构特征、厚度发展特征及其中的脉动分布情况,明确了该风洞射流剪切层所特有的流动结构.

Based on the platform of 1：15 3/4 open - type vehicle model wind tunnel and by means of hot - wire anemometer, instantaneous velocity of the jet shear layer flow was measured in different conditions of col- lector angles and under different nozzle velocities. Through comparative analysis of the average speed and velocity fluctuation, features of jet shear layer＇s structure and thickness, and distribution of velocity fluctuation in different conditions of collector angles were found. The specific jet shear layer structure of unsteady flow in this kind of model wind tunnel was clear.