During blowoff extinction of clear cast PMMA rods in concurrent axial flow for microgravity BASS-II experiments, a dynamic flame oscillation was observed after the flame was blown off of the stagnation point but briefly stabilized on the periphery of the rod. Complementary normal gravity experiments were conducted and flame oscillations were tracked using a high-speed color camera at 240 frames per second. The side-stabilized flame oscillated up and down the rod with increasing amplitude until the entire flame extinguished. In none of the BASS-II or normal gravity tests could the side-stabilized flames persist (Hopf subcritical bifurcation). Since the oscillations occurred even in microgravity, the mechanism does not depend on gravity. For the larger fuel radius tests, the flame developed asymmetric oscillation (pitchfork bifurcation). The oscillation time and the number of oscillations scale with the inverse square of the rod radius (∼ Fourier no.) for the preheated microgravity rods. The average flame oscillation frequency is found to be linearly dependent on the mixed convective stretch rate (inverse of the flow time). The flame intensity varied in concert with its direction, either increasing or decreasing as the flame moved upstream or downstream, respectively. The oscillation frequency decreased as the amplitude increased and the flame slipped slightly farther down the rod with each oscillation. The flame speed increased with each subsequent oscillation, both flashing forward upstream and retreating downstream. The oscillations were found to closely follow a power law log-periodic dependence similar to those that describe systems approaching a critical point, such as diffusion-limited aggregation clusters, earthquakes, ruptures, and even stock market crashes. The net flame speeds varied linearly with ambient oxygen concentration, and linearly with the mixed convective stretch rate. Based on these observations, a mechanistic theory of the oscillations is described, and is consistent with the thermodiffusive instability.

在同时进行轴向流进行微重力BASS-II实验的透明铸造PMMA棒吹扫熄灭期间，在火焰从停滞点吹出但短暂稳定在棒的外围后，观察到动态火焰振荡。进行了补充法向重力实验，并使用高速彩色摄像机以每秒240帧的速度跟踪火焰的振荡。侧面稳定的火焰以逐渐增加的幅度上下摆动，直到整个火焰熄灭。在BASS-II或正常重力试验中，侧面稳定的火焰都不会持续存在（霍普夫（Hopf）亚临界分叉）。由于即使在微重力中也会发生振动，因此其机理不依赖于重力。对于较大的燃料半径测试，火焰产生不对称振荡（干草叉分叉）。预热微重力棒的振荡时间和振荡次数与棒半径的平方成反比（〜傅立叶号）。发现平均火焰振荡频率与混合对流拉伸速率（流动时间的倒数）线性相关。火焰强度与其方向一致，随火焰向上游或向下游移动而增加或减少。振荡频率随着振幅的增加而降低，并且每次振荡时，火焰沿棒向下滑动的距离略远。火焰速度随着随后的每次振荡而增加，既向上游闪动又向下游闪动。发现振荡与幂定律对数周期的依赖性密切相关，类似于描述系统接近临界点的那些振荡，例如受扩散限制的聚合集群，地震，破裂甚至股市崩盘。净火焰速度随环境氧气浓度线性变化，随混合对流拉伸速率线性变化。基于这些观察，描述了振荡的机理理论，并且与热扩散不稳定性相一致。