Theoretical and experimental study of the dependence of transient pipe friction on turbulence dynamics

预测管道非定常流动精度的提高开辟了新的研究领域，例如基于瞬态的泄漏检测，这反过来又要求流动模型具有更高的精度。对管道壁面非定常摩擦的模拟是阻碍研究进展的最大障碍之一。在过去的十年里，人们在直觉上取得了令人印象深刻的进步，但人们普遍认为，由于对瞬态管道流动中的湍流动力学理解不足，进一步的成功受到了阻碍。拟议的项目汇集了一个国际专家团队，在(i)湍流，（ii）瞬态流动分析和（iii）瞬态流动实验方面，集中努力打破理解障碍。目前的知识是如此不足，以至于我们甚至无法预测在瞬态事件（如压力波的传播）中管壁上的轴向剪切力的方向（更不用说它们的振幅）。在2004年3月的一次国际会议上，为这一主题留出了一个完整的讨论环节。来自世界各地许多国家的专家分享了旨在减少不确定性的未来研究的想法。本研究计划的重点是最有希望的前进方向，即研究快速变化管道流动中湍流的轴向、径向和周向分量之间的动态相互作用。在英国和意大利进行的非常详细的数值和实验研究将提供给管道流动分析师使用的一维数值模型的评估。

Improvements in the accuracy of predicting unsteady flows in pipelines have opened up new research areas such as transient-based leak detection that, in turn, are demanding even greater accuracy in flow modelling. One of the biggest barriers to progress is the simulation of unsteady skin friction on pipe walls. There have been impressive intuitive advances in the past decade, but it is generally recognised that further success is hampered by inadequate understanding of turbulence dynamics in transient pipe flows. The proposed project brings together an international team of specialists in (i) turbulence, (ii) transient flow analysis and (iii) transient flow experiments in a focussed bid to break the understanding barrier.Current knowledge is so inadequate that we are not even able to predict the directions of axial shear forces on pipe walls (let alone their amplitudes) during transient events such as the propagation of pressure waves. A full discussion session was set aside for this topic at an international conference in March 2004. Experts from many countries around the world shared ideas for future research aimed at reducing the uncertainty. This research proposal focusses on the most promising way forward, namely studying dynamic interactions between axial, radial and circumferential components of turbulence in rapidly changing pipe flows. Highly detailed numerical and experimental studies in the UK and Italy will feed into assessments of 1-D numerical models used by pipe flow analysts.