Turbulence Structure in a Turbulent Channel Flow with Injection

点击翻译按钮获取中文摘要

An experimental study was carried out on a fully developed turbulent channel flow with uniform injection through the porous wall at five injection rates. Measurement were made of fluctuations of stream-wise and transverse velocity as well as the time-averaged velocity profiles by mean of hot-wire anemometer. The statistical properties, which were included energy spectrum, auto-correlation and probability density function, were investigated. Organized structure was analyzed applying conditional sampling with VITA technique and quadrant analysis.The main effects of injection on the turbulence structure can be summarized as follows. (1). Turbulence intensities and Reynolds shear stress increase with increasing the injection rate. (2). One-point double correlation coefficient is constant and independent of the injection rate. (3). The effect of injection for energy spectrum is restricted in the near wall region. Local isotropy turbulence hypothesis can be applied to injection flow. (4). The contribution from sweep event of bursting phenomenon and bursting frequency injection. This is the reason why Reynolds shear stress increase by injection.