项目名称: 合成射流控制圆柱绕流涡脱落模式及其机理的实验研究
项目编号: No.11202015
项目类型: 青年科学基金项目
立项/批准年度: 2013
项目学科: 数理科学和化学
项目作者: 冯立好
作者单位: 北京航空航天大学
项目金额: 28万元
中文摘要: 基于钝体绕流卡门涡周期性反对称脱落会引起结构振动、诱发气动噪声这一物理现象,本项目提出了合成射流控制圆柱绕流的一种新的思路:改变尾迹涡固有的脱落模式。拟利用一对对称放置于圆柱上下两侧的二维合成射流控制圆柱绕流,通过调节来流雷诺数、射流出口方位角、激励振幅以及激励频率等,改变圆柱尾迹涡固有的反对称脱落模式,例如抑制尾迹涡脱落、诱导产生对称脱落模式等。主要通过水槽中的流动显示以及PIV测量速度场对该问题进行研究,借助本征正交分解(POD)、动力学模态分解(DMD)等多种数据处理技术,分析尾迹涡演化发展的动力学过程,揭示合成射流漩涡与圆柱壁面边界层/剪切层/尾迹涡相互作用的物理机制,研究尾迹涡脱落模式变化对流场、分离以及阻力特性的影响,分析不同流动状态下激励参数的影响规律进而获得合成射流有效控制的优化参数,最终为合成射流控制涡脱落模式这一新思路提供充实的科学依据。
中文关键词: 流动控制;合成射流;圆柱绕流;涡脱落模式;控制机理
英文摘要: Based on the physical phenomenon that the periodical antisymmetric shedding process of Karman vortex induced by flow around a bluff body might lead to the vortex-induced vibration and aerodynamic noise, a novel method for control of flow around a circular cylinder has been proposed for this project: changing the inherent vortex shedding mode. In this study, a pair of two-dimensional synthetic jets which are positioned symmetrically on the cylinder surface will be used to control the flow field. Various experimental parameters, including the Reynolds number based on the cylinder diameter, synthetic jet azimuth angle,excitation amplitude, and excitation frequency, will be adjusted, in order to change the antisymmetric vortex shedding mode, such as the suppression of vortex shedding and the occurrence of the symmetric shedding mode. The project will be conducted in a water channel by using flow visualization techniques and PIV measurements. Different data processing techniques, such as proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD), will be adopted to study the vortex dynamics under synthetic jet control. Particular attention will be paid on the reveal of the physics mechanisms of the interactions between the synthetic jet vortex pair and the cylinder boundary layer/shear layer/wake vor
英文关键词: Flow control;synthetic jet;flow around a circular cylinder;vortex shedding mode;control mechanism