Flow Control with Ink-jet Printed Polymer Surfaces

总体目标是设计使用各种聚合物制造的各种纹理表面（静态和时间相关），在活性表面的情况下，这些聚合物是电活性的。纹理表面将采取多种形式：聚合物喷墨打印可以直接产生静态的条纹阵列，其尺寸旨在最大限度地减少阻力。该技术可以扩展到带有电极（例如石墨）的电活性聚合物（EAP）的打印，以便根据飞行条件重新配置纹线。因此，“智能”波纹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，或者调整其配置以考虑任何侵蚀的影响，从而大大延长其使用寿命。从长远来看（即作为随后几年工作的一部分），将开发技术来驱动湍流边界层下的展向行波。该技术目前正在PI团队的研发中，在低雷诺数下，其阻力降低效果是静态纹波的三倍（30%）。它还有待在高雷诺数下验证。我们提出的具有嵌入式电气驱动和控制的连续单片EAP表面在易于制造，低维护和环境稳健性方面具有几个优势，所有这些都对航空领域非常有吸引力。

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.