A calibrated delayed detached eddy simulation of a sub-scale cold-gas dual-bell nozzle flow at high Reynolds number and in sea-level mode is carried out at nozzle pressure ratio NPR = 45.7. In this regime the over-expanded flow exhibits a symmetric and controlled flow separation at the inflection point, that is the junction between the two bells, leading to the generation of a low content of aerodynamic side loads with respect to conventional bell nozzles. The nozzle wall-pressure signature is analyzed in the frequency domain and compared with the experimental data available in the literature for the same geometry and flow conditions. The Fourier spectra in time and space (azimuthal wavenumber) show the presence of a persistent tone associated to the symmetric shock movement. Asymmetric modes are only slightly excited by the shock and the turbulent structures. The low mean value of the side-loads magnitude is in good agreement with the experiments and confirms that the inflection point dampens the aero-acoustic interaction between the separation-shock and the detached shear layer.

在喷嘴压力比 NPR = 45.7 下，在高雷诺数和海平面模式下对亚尺度冷气双钟形喷嘴流进行校准延迟分离涡模拟。在这种情况下，过度膨胀的流动在拐点处表现出对称和受控的流动分离，即两个钟罩之间的连接点，导致相对于传统钟形喷嘴产生低含量的空气动力学侧向载荷。在频域中分析喷嘴壁压力特征，并与文献中可用的实验数据进行比较，以获得相同的几何形状和流动条件。时空傅立叶谱（方位波数）显示存在与对称冲击运动相关的持久音调。非对称模式仅受到冲击和湍流结构的轻微激发。侧向载荷大小的低平均值与实验非常吻合，并证实拐点抑制了分离冲击和分离剪切层之间的气动声学相互作用。