Study of Vortex Structures in 3D Unsteady Aerodynamics using Experiment and Simulation

随着航天飞机计划的终止，一个接替计划的挑战出现了。为了使进入太空既可行又负担得起，我们必须在目前对航空航天设计的各个方面的理解上取得巨大的飞跃，尤其是推进系统。这种对我们当前空间访问系统的重新发明带来了对航天器新概念的需求：单级入轨（SSTO）可重复使用的运载火箭。它们试图通过消除在发射期间丢弃的部件的需要来解决实现低地球轨道的高成本问题，从而大大减少更换部件所需的经常性成本。他们成功的一个关键方面是推进系统，它在整个任务剖面中有效地运行，从起飞到轨道。其中一种方法是联合循环混合动力发动机，它利用空气呼吸和火箭模式来实现近地轨道。然而，由于每种推进模式都有其优点和缺点，因此必须要求发动机在飞行过程中有效地在模式之间转换，以便在最谨慎的情况下利用每种模式。这就要求其设计高度复杂，以最大限度地提高发动机在每个不同阶段的效率。迄今为止，还没有成功操作过可重复使用的运载火箭（从地球发射）。因此，把研究精力集中在这些飞行器及其子系统的早期设计上是合理的。泰勒博士最近在这个方向上的工作特别强调了超燃冲压发动机，他提出了一种新工具的概念，用于初始设计和优化混合动力发动机的性能和配置，并特别考虑了超燃冲压发动机的模式。与此同时，研究人员还对高超音速发动机进气道和总装所产生的激波模式的复杂行为进行了研究，并特别关注了它们对燃烧过程的影响。

With the termination of the Space Shuttle program, the challenge emerges for a successor strategy to take its place. For access to space to be both feasible and affordable, vast leaps forward must be taken in our current understanding of all aspects of aerospace design, not least importantly propulsion systems. This reinvention of our current space access systems has brought about the need for a new concept of spacecraft to be implemented: The single-stage-to-orbit (SSTO) re-usable launch vehicle. They seek to address the high cost of achieving low-earth orbit by removing the need for parts jettisoned during launch, significantly reducing the recurring costs required in their replacement. A key aspect to their success is a propulsion system which operates efficiently across the whole mission profile, from take-off to orbit. One such approach is the combined cycle hybrid engine, which utilizes both air-breathing and rocket modes to achieve low-earth orbit. However, as each propulsive mode has both its benefits and its drawbacks, the engine must be required to effectively transition between modes mid-flight, in order to utilise each mode when most prudent. This requires a high level of complexity in its design to maximise the engines' efficacy in each distinct phase. To date, there has been no successfully operated re-usable launch vehicles (launched from Earth). It is therefore reasonable to concentrate research efforts on the early stage design of these craft and their subsystems. Dr Taylor's recent work in this direction has had a particular emphasis on scramjet engines, with the conception of a novel tool for the initial design and optimisation of both performance and configuration of hybrid engines, with specific consideration for the scramjet mode. This has been conducted alongside investigations into the complicated behaviour of shock patterns generated as a result of the inlet and general assembly of hypersonic engines, with special attention given to their influence on combustion processes.