ABSTRACT In order to analyse the flow characteristics of free-surface vortexes and to validate the Burgers vortex model by using stereo particle image velocimetry, experiments are conducted in a 600 mm diameter vortex tank. Measured axial velocities indicate that 10–25% of the flow is transported through the vortex core. The velocity profiles show that the axial flow is concentrated in a domain bounded by two times the core radius. Despite Burgers’ assumption of radially independent axial velocity profiles, the model quantifies the tangential velocity profile within a relative uncertainty of circa 10%. The measurements show that it seems valid to use Burgers’ model to obtain an estimate for the core radius by taking the average axial velocity over a radial domain of approximately 2.2 times the core radius. The Burgers model quantifies the air core depth with an uncertainty of 20% relative to the measurements. When compared with the magnitude of vorticity diffusion by molecular viscosity, the experiments show that there is no significant diffusion by radial turbulence.

中文翻译：

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使用立体 PIV 的自由表面涡旋 3D 流场的实验研究

摘要 为了分析自由表面涡流的流动特性并利用立体粒子图像测速法验证 Burgers 涡流模型，在直径 600 mm 的涡流槽中进行了实验。测得的轴向速度表明 10-25% 的流量通过涡核传输。速度剖面显示轴向流集中在两倍于核心半径的区域内。尽管 Burgers 假设了径向独立的轴向速度剖面，但该模型在大约 10% 的相对不确定性内量化了切向速度剖面。测量结果表明，使用 Burgers 模型通过取大约 2.2 倍核心半径的径向域上的平均轴向速度来估计核心半径似乎是有效的。Burgers 模型以相对于测量值 20% 的不确定性来量化空心深度。与分子黏度的涡度扩散大小相比，实验表明径向湍流不存在显着的扩散。