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燃烧室流场中旋涡的不稳定是造成整体式冲压式发动机侧面突扩燃烧室燃烧振荡的重要原因。在透明矩形侧面突扩燃烧室模型上进行了水流模拟显示实验。显示出了燃烧室流场中的振荡涡系和稳定涡系。实验发现：燃烧室头部旋涡非常稳定；进口射流剪切层存在＂马蹄涡＂的周期性脱落；射流在燃烧室通道内卷绕形成涡强较大的二次流螺旋柱状涡对，涡对相撞又使螺旋涡失稳、振荡和破碎。旋涡不稳定性是侧面突扩燃烧室燃烧振荡的流体力学原因。分流的加入挤碎了＂马蹄涡＂，消除了射流势核尾部的旋涡扰动。同时，分流射流横向扩展继续为螺旋柱状旋涡提供足够的涡量，使其稳定旋转。加入分流后的侧面突扩燃烧室在地面热试中燃烧非常稳定。采用Ｓｉｍｐｌｅ方法，通过联立求解定常时均流输运方程和ｋ－ε双方程湍流模型得出了无分流侧面突扩燃烧室和侧面分流突扩燃烧室冷态流场速度分布。除了不稳定流动区域，计算结果与流场显示结果符合良好。
The vortex instability in the flow field in the combustion chamber is the main reason that causes the combustion oscillation of the sudden expansion and combustion chamber on the side of the integral ramjet. A simulation experiment of water flow was carried out on a transparent rectangular flaring combustion chamber model. The oscillation vortex system and the stable vortex system in the combustor flow field are shown. It is found that the vortex in the head of the combustor is very stable. The inlet shear layer has periodic shedding of “horseshoe vortex”. The jet is wound in the channel of the combustion chamber to form the secondary spiral helix vortex with large eddy strength. The collision also makes the spiral vortex instability, oscillation and broken. Vortical instability is the hydrodynamic cause of combustion oscillations in a side-protruding combustor. The addition of shunts squeezed the “horseshoe vortex”, eliminating vortex perturbations at the rear of the jet potential nuclei. At the same time, the lateral expansion of the shunt jet continues to provide sufficient vorticity for the helical columnar vortex to rotate stably. After adding the shunt side of the sudden expansion combustion chamber burning in the ground test is very stable. The Simple method was used to obtain the velocity distribution of the cold flow field in the splitless side suddenly expanding combustor and the side split sudden expansion combustor by solving the steady flow equation and the k-ε two-equation turbulence model. Except for the unstable flow area, the calculated result is in good agreement with the flow field.