High-fidelity computational fluid dynamics (HF-CFD) has revealed the potential for high-frequency flow instabilities (aka “turbulent-like” flow) in intracranial aneurysms, consistent with classic in vivo and in vitro reports of bruits and/or wall vibrations. However, HF-CFD has typically been performed on limited numbers of cases, often with unphysiological inflow conditions or focused on sidewall-type aneurysms where flow instabilities may be inherently less prevalent. Here we report HF-CFD of 50 bifurcation aneurysm cases from the open-source Aneurisk model repository. These were meshed using quadratic finite elements having an average effective spatial resolution of 0.065 mm, and solved under physiologically-pulsatile flow conditions using a well-validated, minimally-dissipative solver with 20,000 time-steps per cardiac cycle Flow instability was quantified using the recently introduced spectral power index (SPI), which quantifies, from 0 to 1, the power associated with velocity fluctuations above those of the driving inflow waveform. Of the 50 cases, nearly half showed regions within the sac having SPI up to 0.5, often with non-negligible power into the 100's of Hz, and roughly 1/3 had sac-averaged SPI > 0.1. High SPI did not significantly predict rupture status in this cohort. Proper orthogonal decomposition of cases with highest SPI_avg revealed time-varying energetics consistent with transient turbulence. Our reported prevalence of high-frequency flow instabilities in HF-CFD modelling of aneurysms suggests that care must be taken to avoid routinely overlooking them if we are to understand the highly dynamic mechanical forces to which some aneurysm walls may be exposed, and their prevalence in vivo.

高保真计算流体动力学（HF-CFD）已揭示了在颅内动脉瘤的高频流动不稳定性（又名“湍流状”流），与经典的一致的电位在体内和体外杂音和/或墙壁振动的报告。然而，HF-CFD 通常在有限数量的情况下进行，通常具有非生理性流入条件或侧重于侧壁型动脉瘤，其中流动不稳定性可能天生不那么普遍。在这里，我们报告了来自开源 Aneurisk 模型库的 50 个分叉动脉瘤病例的 HF-CFD。这些使用平均有效空间分辨率为 0.065 mm 的二次有限元进行网格划分，并在生理脉动流动条件下使用经过充分验证的最小耗散求解器求解，每个心动周期有 20,000 个时间步长。引入了频谱功率指数 (SPI)，该指数从 0 到 1 量化与驱动流入波形的速度波动相关的功率。在这 50 个案例中，近一半显示囊内区域的 SPI 高达 0.5，通常具有不可忽略的功率到 100 赫兹，大约 1/3 的囊平均 SPI > 0.1。在该队列中，高 SPI 并未显着预测破裂状态。具有最高 SPI 的案例的正确正交分解_avg揭示了与瞬态湍流一致的时变能量学。我们报告的动脉瘤 HF-CFD 建模中高频流动不稳定性的普遍性表明，如果我们要了解某些动脉瘤壁可能受到的高动态机械力及其在动脉瘤中的普遍性，必须小心避免经常忽视它们。体内。