Institute for Computational Mechanics, Technical University of Munich, Munich, Germany.
Int J Numer Method Biomed Eng. 2019 Dec;35(12):e3228. doi: 10.1002/cnm.3228. Epub 2019 Oct 10.
This work uses high-order discontinuous Galerkin discretization techniques to simulate transitional and turbulent flows through medical devices. Flows through medical devices are characterized by moderate Reynolds numbers and typically involve different flow regimes such as laminar, transitional, and turbulent flows. Previous studies for the FDA benchmark nozzle model revealed limitations of Reynolds-averaged Navier-Stokes turbulence models when applied to more complex flow scenarios. Recent works based on large-eddy simulation approaches indicate that these limitations can be overcome but also highlight potential limitations due to a high sensitivity with respect to numerical parameters. The methodology presented in this work introduces two novel ingredients compared with previous studies. Firstly, we use high-order discontinuous Galerkin methods for discretization in space. The inherent dissipation and dispersion properties of high-order discontinuous Galerkin discretizations are expected to render this approach well suited for transitional and turbulent flow simulations. Secondly, to mimic blinded CFD studies, we propose to use a precursor simulation approach in order to predict the inflow boundary condition for laminar, transitional, and turbulent flow regimes instead of prescribing analytical velocity profiles at the inflow. We investigate the whole range of Reynolds numbers as suggested by the FDA benchmark nozzle problem and compare the numerical results to experimental data obtained by particle image velocimetry in order to critically assess the predictive capabilities of the solver on the one hand and the suitability of the FDA nozzle problem as a benchmark in computational fluid dynamics on the other hand.
这项工作使用高阶间断 Galerkin 离散化技术来模拟通过医疗设备的过渡流和湍流。医疗设备中的流动具有中等雷诺数，通常涉及不同的流动状态，如层流、过渡流和湍流。以前对 FDA 基准喷嘴模型的研究表明，当应用于更复杂的流动情况时，雷诺平均纳维-斯托克斯湍流模型存在局限性。基于大涡模拟方法的最新研究表明，这些局限性是可以克服的，但也强调了由于对数值参数的高度敏感性而可能存在的局限性。与以前的研究相比，这项工作提出的方法有两个新的特点。首先，我们在空间离散化中使用高阶间断 Galerkin 方法。高阶间断 Galerkin 离散化的固有耗散和弥散特性有望使这种方法非常适合过渡流和湍流模拟。其次，为了模拟盲 CFD 研究，我们建议采用前导模拟方法来预测层流、过渡流和湍流的入口边界条件，而不是在入口处规定解析速度剖面。我们研究了 FDA 基准喷嘴问题所建议的整个雷诺数范围，并将数值结果与粒子图像测速法获得的实验数据进行比较，一方面评估求解器的预测能力，另一方面评估 FDA 喷嘴问题作为计算流体动力学基准的适用性。
