Reduction of friction drag in subsonic flow via feedback control

通过反馈控制减少亚音速流中的摩擦阻力

• 批准号: 202189428
• 负责人: Professor Dr.-Ing. Dirk Abel
• 金额: --
• 依托单位: Lehrstuhl und Institut für Regelungstechnik (IRT)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/202189428?language=en
• 关键词: Reduction; friction; drag; subsonic; flow

During the first funding period of the research group ¿Active drag reduction via wavy surface oscillation¿ model reduction for distributed parameter systems and subsequent model based control strategies have been investigated by subproject 3. First, the methods were applied to onedimensional sample systems and then, they have been transferred to the 3D-Navier-Stokes case. However, only steady inflow conditions have been considered so far. These results are to be transferred to time dependent inflow conditions in the second funding period. At first, the inflow conditions are assumed to be known to the controller. Using this information an open-loop disturbance rejection can be established. In a second step, this information will not be provided to the controller. The inflow condition becomes an unknown disturbance, which can be only determined from its influence on the friction drag. Thus, the plant model has to span the whole operating range of possible inflow conditions. For the accompanying model reduction, different methods to generate a functional basis are investigated additionally to the Proper Orthogonal Decomposition, which has already been used. The results from this comparison are used in the next step to set up a parametric reduced-order model. This model can either be built from a global basis or from an interpolation between set of local bases. The controller should include the knowledge from this extended model. For this purpose, nonlinear methods are investigated as well as robust approaches. For the latter, one idea to reduce the conservatism in the design is to incorporate knowledge about the probability distribution of the inflow condition.

在研究小组的第一个资助期间，通过波浪表面振荡进行主动减阻，子项目3研究了分布式参数系统的模型缩减以及随后基于模型的控制策略。首先，将该方法应用于一维样品系统，然后将其应用于三维navier - stokes情况。然而，到目前为止，只考虑了稳定的流入条件。这些结果将在第二个资助期转移到随时间变化的流入条件。首先，假定流入条件是控制器已知的。利用这些信息可以建立开环抑制干扰。在第二步中，将不向控制器提供此信息。流入条件成为一个未知的扰动，只能通过其对摩擦阻力的影响来确定。因此，工厂模型必须跨越可能流入条件的整个运行范围。对于相应的模型约简，除了已经使用的适当正交分解之外，还研究了生成函数基的不同方法。该比较的结果将用于下一步建立参数化降阶模型。该模型既可以建立在全局基础上，也可以建立在一组局部基础之间的插值上。控制器应该包含来自这个扩展模型的知识。为此，研究了非线性方法和鲁棒方法。对于后者，在设计中降低保守性的一种思路是纳入入流条件概率分布的知识。