Flow Control with Ink-jet Printed Polymer Surfaces

主要目标是设计各种纹理表面(包括静态的和时间相关的)，使用各种聚合物制造，在活性表面的情况下，这是电活性的。纹理表面将采取多种形式：聚合物喷墨打印可以直接产生尺寸设计为最大减阻的静态肋骨阵列。该技术可扩展到具有电极(例如，石墨)的电活性聚合物(EAP)的印刷，从而使肋片可重新配置以适应飞行条件。因此，“智能”肋片可以在飞行中进行优化，以最大限度地减少整个飞行包线的阻力，或者调整它们的配置，以考虑到任何侵蚀的影响，从而大大延长它们的使用寿命。在较长期内(即作为以后几年工作的一部分)，将开发出在湍流边界层下驱动跨向行波的技术。这项技术目前正在PI的小组中开发，众所周知，在低雷诺数时，这种技术的减阻效果大约是静态肋片(30%)的三倍。在高雷诺数的情况下，这一点还有待验证。我们提出的具有嵌入式电驱动和控制的连续整体式EAP表面在制造容易、维护成本低和环境稳健性方面具有几个优点，所有这些都对航空部门非常有吸引力。

The overarching goal is to design a variety of textured surfaces (both static and time-dependent) fabricated using a variety of polymers, which, in the case of active surfaces, are electroactive. The textured surfaces will take a variety of forms: polymer ink-jet printing can straightforwardly produce a static array of riblets of dimensions designed for maximum drag reduction. The technique may be extended to the printing of Electroactive Polymer (EAP) with electrodes (e.g. graphite) so that the riblets are re-configurable for the flight condition. Therefore 'smart' riblets may be optimised in-flight for maximum drag reduction throughout the flight envelope, or, their configuration adjusted to account for any effects of erosion, so considerably extending their lifetime. In the longer term (i.e. as part of work in subsequent years), the techniques will be developed to drive spanwise travelling waves beneath the turbulent boundary layer. This technique, currently under development in the PI's group, is known to lead to drag reductions roughly three times that possible with static riblets ( 30%) at low Reynolds numbers. It has yet to be verified at high Reynolds numbers. Our proposal of a continuous monolithic EAP surface with embedded electrical actuation and control offers several advantages in terms of ease of manufacture, low maintenance and environmental robustness, all of which are very attractive to the aeronautical sector.