Pressure oscillations are one of the most important challenges of high slenderness ratio solid rocket motors. The cause of these oscillations can be traced to the vortex shedding due to grain burning areas, holes and slots. In this paper, a four segments grain of space shuttle boosters and the structure of Ariane 5 small-scale motors are used to evaluate aeroacoustic pressure oscillations. First, the related parameters to scale down were determined using Buckingham's Pi-theorem, and then a small-scale 1:31 motor was designed and manufactured. Next, the number of Strouhal in different grain forms and the prediction criteria of vortex shedding were discussed. In the next step, to understand the internal flow of the motor and the formation of vortex shedding, the dynamic calculation of the steady state computational fluid was performed in seven regression steps and finally, two static tests were performed to validate the analysis and simulation. The results show that different definitions for the Strouhal number are useful only for the first glance at the vortex shedding and pressure oscillations, and therefore the CFD solution and test program for a correct understanding of the ballistic operational condition of the motor is inevitable. In addition, despite aggress of pressure test data and grain-burning regression of sub-scaled motor to full-scale motor, the internal flow phenomenon may be different from the scale motor due to its small-scale time and dimensions.

压力振荡是高细长比固体火箭发动机的最重要挑战之一。这些振荡的原因可以归结为由于谷物燃烧区，孔和槽而引起的涡旋脱落。在本文中，使用四段式航天飞机助推器和Ariane 5小型电动机的结构来评估空气声压力振荡。首先，使用白金汉氏定理确定按比例缩小的相关参数，然后设计和制造小型1:31电动机。接下来，讨论了不同晶型下的Strouhal数量以及涡旋脱落的预测标准。在下一步中，要了解电动机的内部流动以及涡流脱落的形成，通过七个回归步骤对稳态计算流体进行了动态计算，最后进行了两次静态测试以验证分析和仿真结果。结果表明，对于Strouhal数，不同的定义仅可用于乍一看涡旋脱落和压力振​​荡，因此不可避免地需要CFD解决方案和测试程序来正确理解电动机的弹道工作条件。另外，尽管压力测试数据激进并且子级电动机向全尺寸电动机燃烧燃烧回归，但是由于其小规模的时间和尺寸，内部流动现象可能与规模电动机不同。结果表明，斯特洛哈尔数的不同定义仅对于乍一看涡旋脱落和压力振​​荡有用，因此，不可避免地需要CFD解决方案和测试程序来正确理解电动机的弹道工作条件。另外，尽管压力测试数据激进并且子级电动机向全尺寸电动机燃烧燃烧回归，但是由于其小规模的时间和尺寸，内部流动现象可能与规模电动机不同。结果表明，斯特洛哈尔数的不同定义仅对于乍一看涡旋脱落和压力振​​荡有用，因此，不可避免地需要CFD解决方案和测试程序来正确理解电动机的弹道工作条件。另外，尽管压力测试数据激进并且子级电动机向全尺寸电动机燃烧燃烧回归，但是由于其小规模的时间和尺寸，内部流动现象可能与规模电动机不同。